Forte Biosciences, Inc. - Annual Report: 2017 (Form 10-K)

UNITED STATES

SECURITIES AND EXCHANGE COMMISSION

Washington, D.C. 20549

FORM 10-K

(Mark One)

For the fiscal year ended December 31, 2017

OR

Commission File Number 001-38052

TOCAGEN INC.

(Exact name of registrant as specified in its Charter)

Registrant’s telephone number, including area code: (858) 412-8400

Securities registered pursuant to Section 12(b) of the Act:

Securities registered pursuant to 12(g) of the Act: None

Indicate by check mark if the registrant is a well-known seasoned issuer, as defined in Rule 405 of the Securities Act. YES ☐ NO ☒

Indicate by check mark if the registrant is not required to file reports pursuant to Section 13 or 15(d) of the Act. YES ☐ NO ☒

Indicate by check mark whether the registrant: (1) has filed all reports required to be filed by Section 13 or 15(d) of the Securities Exchange Act of 1934 during the preceding 12 months (or for such shorter period that the registrant was required to file such reports), and (2) has been subject to such filing requirements for the past 90 days. YES ☒ NO ☐

Indicate by check mark whether the registrant has submitted electronically and posted on its corporate Web site, if any, every Interactive Data File required to be submitted and posted pursuant to Rule 405 of Regulation S-T (§232.405 of this chapter) during the preceding 12 months (or for such shorter period that the registrant was required to submit and post such files). YES ☒ NO ☐

Indicate by check mark if disclosure of delinquent filers pursuant to Item 405 of Regulation S-K (§229.405) is not contained herein, and will not be contained, to the best of registrant’s knowledge, in definitive proxy or information statements incorporated by reference in Part III of this Form 10-K or any amendment to this Form 10-K. ☒

Indicate by check mark whether the registrant is a large accelerated filer, an accelerated filer, a non-accelerated filer, smaller reporting company, or an emerging growth company. See the definitions of “large accelerated filer,” “accelerated filer,” “smaller reporting company,” and “emerging growth company” in Rule 12b-2 of the Exchange Act.

If an emerging growth company, indicate by check mark if the registrant has elected not to use the extended transition period for complying with any new or revised financial accounting standards provided pursuant to Section 13(a) of the Exchange Act.  ☒

Indicate by check mark whether the registrant is a shell company (as defined in Rule 12b-2 of the Exchange Act). YES ☐ NO ☒

The aggregate market value of the voting and non-voting common equity held by non-affiliates of the registrant as of June 30, 2017 (the last business day of the registrant’s most recently completed second fiscal quarter) was approximately $217 million based on the closing price of the registrant’s common stock on June 30, 2017 of $12.03 per share, as reported by the NASDAQ Global Select Market.

As of February 28, 2018, there were 19,911,616 shares of the registrant’s common stock outstanding.

DOCUMENTS INCORPORATED BY REFERENCE

Portions of the registrant’s definitive proxy statement to be filed with the Securities and Exchange Commission, or SEC, subsequent to the date hereof pursuant to Regulation 14A in connection with the registrant’s 2018 Annual Meeting of Stockholders, are incorporated by reference into Part III of this Annual Report on Form 10-K. Such proxy statement will be filed with the SEC not later than 120 days after the conclusion of the registrant’s fiscal year ended December 31, 2017.

Table of Contents

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SPECIAL NOTE REGARDING FORWARD-LOOKING STATEMENTS

This Annual Report on Form 10-K contains forward-looking statements. The forward-looking statements are contained principally in the sections entitled “Risk Factors,” “Management’s Discussion and Analysis of Financial Condition and Results of Operations” and “Business.” These statements relate to future events or to our future financial performance and involve known and unknown risks, uncertainties and other factors which may cause our actual results, performance or achievements to be materially different from any future results, performance or achievements expressed or implied by the forward-looking statements. Forward-looking statements include, but are not limited to, statements about:

In some cases, you can identify these statements by terms such as “anticipate,” “believe,” “could,” “estimate,” “expects,” “intend,” “may,” “plan,” “potential,” “predict,” “project,” “should,” “will,” “would” or the negative of those terms, and similar expressions that convey uncertainty of future events or outcomes. These forward-looking statements reflect our management’s beliefs, opinions and views with respect to future events and are based on estimates, assumptions and information available to us as of the date of this Annual Report on Form 10-K, and while we believe such information forms a reasonable basis for such statements, such information may be limited or incomplete and our statements should not be read to indicate that we have conducted an exhaustive inquiry into, or review of, all potentially available relevant information. These statements are inherently uncertain and are subject to risks and uncertainties. We discuss many of these risks in greater detail under the heading “Risk Factors.” Moreover, we operate in a very competitive and rapidly changing environment. New risks emerge from time to time. It is not possible for our management to predict all risks, nor can we assess the impact of all factors on our business or the extent to which any factor, or combination of factors, may cause actual results to differ materially from those contained in any forward-looking statements we may make. Given these uncertainties, you should not place undue reliance on these forward-looking statements.

You should carefully read this Annual Report on Form 10-K and the documents that we reference herein and have filed as exhibits to the Annual Report on Form 10-K completely and with the understanding that our actual future results may be materially different from what we expect. We qualify all of the forward-looking statements in this Annual Report on Form 10-K by these cautionary statements.

Except as required by law, we assume no obligation to update these forward-looking statements publicly, or to update the reasons actual results could differ materially from those anticipated in any forward-looking statements, whether as a result of new information, future events or otherwise. 

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PART I

Item 1. Business.

Overview

We are a clinical-stage, cancer-selective gene therapy company focused on developing first-in-class, broadly-applicable product candidates designed to activate a patient’s immune system against their own cancer from within. Our cancer-selective gene therapy platform is built on retroviral replicating vectors, or RRVs, which are designed to selectively deliver therapeutic genes into the DNA of cancer cells. Our gene therapy approach is designed to fight cancer through immunotherapeutic mechanisms of action without the autoimmune toxicities commonly experienced with other immunotherapies. Our founding vision is “No One Should Die Of Cancer” because we believe the immune system can be safely activated to fight the patient’s cancer.

We are developing our lead product candidate, Toca 511 (vocimagene amiretrorepvec) & Toca FC (flucytosine), initially for the treatment of recurrent high grade glioma, or HGG, a brain cancer with limited treatment options, low survival rates and, therefore, a significant unmet medical need. We are conducting a randomized, controlled Phase 3 clinical trial of Toca 511 & Toca FC in patients with recurrent HGG, which is designed to serve as a registrational trial. In February 2017, the U.S. Food and Drug Administration, or FDA, granted Toca 511 & Toca FC Breakthrough Therapy Designation for the treatment of patients with recurrent HGG and in June 2017 the European Medicines Agency, or EMA, granted Toca 511 Priority Medicines, or PRIME, Designation for the treatment of patients with glioma. Breakthrough Therapy Designation indicates that preliminary clinical evidence demonstrates the drug may have substantial improvement on one or more clinically significant endpoints over available therapy. PRIME Designation indicates that there is a potential to benefit patients with unmet medical needs based on early clinical data. We also have Fast Track Designation (which may lead to expedited regulatory review of new products that treat serious diseases or conditions and demonstrate the potential to address an unmet medical need) from the FDA for Toca 511 & Toca FC for the treatment of recurrent HGG and Orphan-Drug Designation (a designation for a product that treats a rare disease or condition and which, if the product receives the first FDA approval for that disease or condition, may result in a period of regulatory exclusivity, subject to some exceptions) for the treatment of HGG.  The Committee for Orphan Medicinal Products of the EMA has designated both flucytosine and vocimagene amiretrorepvec as orphan medicinal products indicated for the treatment of glioma. The EMA provides several benefits to drug developers for developing drugs for orphan diseases.

We have conducted three ascending dose Phase 1 clinical trials involving 127 recurrent HGG patients. In these trials, we investigated three modes of Toca 511 delivery: injection into the cavity wall after surgical resection of the recurred tumor (n=56), direct intratumoral injection without resection (n=54), and intravenous administration followed, approximately one to two weeks later, by resection with further local vector delivery at the time of resection (n=17). Administration of Toca 511 was followed with cycles of Toca FC. In these trials, we observed potential benefits, including durable objective responses, extended overall survival compared to historical controls and a favorable safety profile. We did not reach a dose-limiting toxicity in any of these trials. Based on these Phase 1 clinical trial results, we are conducting a Phase 3 clinical trial which is designed to serve as a potential registrational trial in patients with first or second recurrent HGG undergoing resection.

As of the data cutoff of August 2017, of the 56 patients enrolled in the ascending-dose resection injection Phase 1 trial, 53 were efficacy evaluable and of those, six patients had a complete response and remain in response. Five of these patients with a complete response were within a subset of 23 patients that mirrors the entry criteria, clinical setting and dosing for patients in our Phase 3 clinical trial. Responses were assessed by independent radiology review of magnetic resonance imaging, or MRI, brain scans. Median duration of response had not been reached after a median follow-up of 35.1 months (range: 9.2 to 44.9 months) which compares favorably to a range of durable responses of 2.79 to 9.62 months in a clinical trial of a drug used as standard of care for recurrent HGG. An association between durable response and overall survival is suggested as all responders remain alive following study entry (range: 21.4 to 52.2 months). As of the data cutoff of August 2017, the subset of 23 patients in our Phase 1 resection injection trial that mirrors the Toca 5 Phase 3 patient population (similar entry criteria, clinical setting and dosing) had a median survival of 14.4 months, with an approximately six-month improvement in median overall survival relative to results from clinical trials of drugs used as standard of care for recurrent HGG. In addition:

Increases in immunologic activity were observed with Toca 511 & Toca FC treatment, including elevations of replicating CD4 (often referred to as “helper” T cells) and CD8 (often referred to as “killer” T cells) T cells in the blood, for patients in some cohorts in the resection injection Phase 1 trial.

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Based on preclinical data, we believe Toca 511 & Toca FC may have therapeutic benefit in multiple other solid tumor cancers, and we initiated a Phase 1b clinical trial in July 2016 of intravenous treatment of metastatic cancers that include colorectal, pancreatic, breast, lung and melanoma cancers, all of which can spread to the brain and other organs. In the Phase 1b trial, Toca 511 will be administered by intravenous injection followed by (1) intratumoral injection following biopsy or (2) injection into the resection cavity wall following planned resection in the case of recurrent HGG or brain metastases. In our completed intravenous clinical trial of Toca 511 for the treatment of recurrent HGG, Toca 511 crossed the blood brain barrier and was detected in brain tumors. In our metastatic cancer trial we plan to evaluate safety, presence of Toca 511 genes in tumors, immunologic activity in the blood and tumor such as changes in CD4 and CD8 T cells and clinical activity such as objective tumor response and clinical benefit. We also plan, in this clinical trial, to evaluate Toca 511 & Toca FC in combination with one or more checkpoint inhibitors.

Based on our findings in preclinical studies and clinical trials to date, we believe Toca 511 & Toca FC is a promising candidate for use in newly diagnosed HGG patients in combination with surgery, radiation and chemotherapy. Therefore, we plan to advance clinical development to evaluate safety and efficacy in this setting with Toca 511 & Toca FC being delivered in conjunction with surgery, radiation and temozolomide.

Our RRV platform is versatile and we believe it has the potential to deliver a wide variety of genes selectively to cancer cells. Our first RRV-based immunotherapy product candidate, Toca 511 & Toca FC, is designed to replicate without cell lysis then directly kill tumor and immune suppressive myeloid cells activating the immune system against cancer through a combination of mechanisms. In addition, we are developing other RRVs to selectively deliver genes to cancer cells against validated immunotherapy targets, such as the checkpoint protein PD-L1. We generated preclinical data supporting the potential anti-cancer benefits of an RRV delivering a gene against PD-L1. In 2018, we plan to conduct IND-enabling studies of our anti-PD-L1 RRV product candidate.

Cancer is the second leading cause of mortality in the United States and accounts for nearly one in four deaths. Early cancer treatments relied on relatively non-specific and highly toxic small molecule chemotherapies. Over the last 20 years, a new paradigm of cancer research and treatment has emerged that is focused on more targeted therapies. Most recently this has included the emergence of immunotherapies that can stimulate a patient’s immune system to slow the growth and the spread of, and ideally, eliminate, cancer cells. These therapies have shown the potential to provide dramatic efficacy and to extend survival for cancer patients even in cases in which conventional therapies, such as surgery, chemotherapy and radiotherapy, have already been used. In 2013, Science magazine named cancer immunotherapy as the biggest breakthrough of the year. With this breakthrough, global pharmaceutical companies as well as a large number of emerging companies are researching and developing new cancer immunotherapy treatments.

Despite these advancements, many current immunotherapies, such as checkpoint inhibitors, chimeric antigen receptor, or CAR, and T cell receptor, or TCR, T cells, are limited by their autoimmune and other side effects. Combination treatments are common in cancer, but combinations of immune mediated treatments with systemic cytotoxic chemotherapy may be challenging as chemotherapy is often damaging to the immune system. Thus, immunotherapies effective enough to be able to displace systemic chemotherapy are needed. The utility of oncolytic viruses alone as immunotherapy has been challenged by lack of specificity to tumor cells, injury to healthy tissues, lack of targeting to specific brakes on the immune system, and short-term effect due to effective clearance of the virus. Consequently, there remains a significant need for immunotherapies that are effective as well as safe and tolerable.

In contrast to current immunotherapies, we believe our RRV platform and lead product candidate have the potential to selectively infect cancer cells to stimulate robust and durable anti-cancer immune responses with minimal toxicity. Our RRVs are designed to selectively integrate into the DNA of cancer cells which then serve as factories to produce more of these RRVs by budding. The progeny RRV infect neighboring cancer cells, providing long-term presence of the therapeutic gene or genes. Our novel therapies are designed to break immune tolerance selectively in the tumor microenvironment.

Toca 511 & Toca FC is designed to break immune tolerance through a combination of mechanisms triggered by the conversion of Toca FC into high levels of 5-FU (5-fluorouracil), an anti-cancer agent, by the therapeutic gene delivered by Toca 511 into the cancer cell. Toca 511 & Toca FC treatment is designed for cycles of sustained production of high levels of 5-FU directly in tumors, which we believe is important for robust and durable anti-cancer immune activation. Cancer cell death releases damage-associated molecular patterns, or DAMPs, pathogen-associated molecular patterns, or PAMPs, and tumor-associated antigens, resulting in antigen presentation and activation of T cells. 5-FU is known to kill cancer cells and immune cells when used systemically. When 5-FU is present locally, it kills immune-suppressive myeloid cells in the tumor micro-environment while leaving systemic immune activity clinically intact. The local immune-suppressive myeloid cells include myeloid-derived suppressor cells, or MDSCs, as well as tumor associated macrophages, or TAMs, which are white blood cells recruited and retained by the tumor that contribute to the suppression of normal immune activity against cancer cells. TAMs and MDSCs suppress the number and activity of CD4 and CD8 T cells and work with the lymphocyte-derived suppressor T cells called regulatory T cells, or Tregs. MDSC and TAM destruction by 5-FU is designed to contribute to immune activation against the tumor-associated antigens. We believe the persistence of the therapeutic gene in the cancer cells has allowed for multiple cycles of Toca FC treatment in our trials, which may result in additional killing of cancer cells and immunosuppressive myeloid cells, leading to enhancement of the strength and durability of the immune response with each successive cycle of Toca FC treatment. Also, in a trial with multiple Toca 511 intravenous infusions followed by resection, we observed increased Toca 511 in the tumor compared to single day infusion.

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We have retained worldwide rights to the development and commercialization of therapeutic product candidates derived from our RRV platform in all indications. We have licensed rights to, and collaborate with, Siemens Healthcare Diagnostics Inc., or Siemens, to develop diagnostics related to the clinical development and future commercialization of Toca 511 & Toca FC. We have intellectual property protection in major markets worldwide, including 76 issued and granted patents and 72 patent applications (foreign and domestic) on our technology platform and novel product candidates, which we believe will maintain coverage from issued patents until approximately 2030. Since inception in 2007, we have funded our operations primarily through the sales of our equity securities from which we received $230.2 million in net proceeds.

Our Proprietary Technology Platform: Harnessing Cancer Immunotherapy and Gene Therapy Together to Fight Cancer

Cancer immunotherapy, also termed immuno-oncology, has recently emerged as an exciting field of cancer therapy with the approval of drugs that aim to enhance anti-cancer immune responses by, for example, overcoming the suppressive mechanisms that cancer cells have developed to evade the immune system. Despite recent advances, current cancer immunotherapies have limitations. They often lead to unwanted and unanticipated autoimmune toxicities. Also, treatment effectiveness may be limited by previous or co-treatment with systemic cytotoxic chemotherapies, which damage the immune system. In addition, knocking out a particular brake on the immune system may not be relevant to a particular clinical setting or the tumor may simply not be immunogenic enough to become a target for immune clearance.

Early promising cancer gene therapies designed to provoke antitumor immune responses predominantly focused on enhancing the activation of the immune system by delivering genes for cytokines. Most of the first generation non-replicating cancer gene therapy viral vectors, however, were limited in their ability to enter and persist in a sufficient number of cancer cells to generate robust and durable anti-cancer immune responses consistently. Second generation cancer gene therapy vectors are replicating and, in the case of immunotherapies, have primarily consisted of oncolytic viruses, which lyse infected cells and activate the immune system against the virus, leading to its rapid clearance.

We believe our investigational gene therapy platform and therapeutic genes represent innovative and differentiated approaches in cancer-selective immunotherapy which have the potential to drive a safe, powerful and durable immune response against cancer, without triggering autoimmunity. We chose to utilize RRVs as the basis of our gene therapy platform for cancer-selective immunotherapy because they exhibit several characteristics that we believe allow us to optimize the safety, delivery and persistence of our therapeutic genes in cancer cells. These characteristics include that they:

Our lead product candidate is a cancer-selective immunotherapy comprised of an investigational biologic, Toca 511, and an investigational small molecule, Toca FC, that are designed to be used together. Toca 511 is an injectable RRV that encodes a prodrug activator enzyme, cytosine deaminase, or CD. Its selective delivery to cancer cells means that the infected cancer cells selectively carry the CD gene and produce CD. Toca FC is an investigational orally administered prodrug, 5-FC, that is inactive as an anti-cancer drug. We believe Toca 511 & Toca FC is a promising choice for the following reasons:

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Our Pipeline

Our Strategy

Our focus is to develop and commercialize first-in-class cancer-selective immunotherapies using our proprietary gene therapy platform. Key elements of our strategy include:

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Immunotherapy and the Emergence of Cancer-Selective Immunotherapy

Background on Cancer and Immunotherapy

Cancer results from damage to the genes of the cell, sometimes exacerbated by underlying genetic defects such as those in oncogene regulation, DNA repair and immune competence. When cancerous cells acquire novel proteins, called tumor-associated antigens, the immune system is believed to act as a surveillance system that can seek and destroy these mutated cells. However, over time, the cancer cell mutation process results in the activation of certain genes and/or the inactivation of others, leading to the ability of the cancer cells to hide from the immune system and grow, eventually becoming malignant and having the ability to invade and destroy healthy tissue. The process of cancer becoming able to hide from the immune system is referred to as developing immune tolerance to the cancer antigens.

To achieve immune tolerance, cancer tissue modifies the immune system by dampening or inactivating key immune mechanisms to thereby allow the cancer to hide from or diminish the immune system. An important example of the mechanism of local immune suppression is the attraction, retention and expansion of immune-suppressive myeloid cells such as MDSCs and TAMs, which are suppressors of immune cell killing of cancer cells both directly and through their support of Tregs. Also, in HGG and other tumors, the cancer cells and infiltrating immune cells often deploy proteins on their cell surface such as PD-L1 to activate the programmed death-1, or PD-1, proteins on the surface of lymphocytes creating a brake on the immune system. The tumor can also produce increased amounts of IDO-1 proteins, which both metabolize and drastically reduce tryptophan, an amino acid important in immune activation, and produce catabolites that are immune-suppressive. The cancer cells may also release cytokines such as TGF-beta which lead to local immune suppression.

In order for a patient to conquer his or her cancer, the patient typically needs treatment that can overcome most or all of these immune tolerance mechanisms. Once tolerance is broken and the patient’s immune system can attack and destroy the cancer, it precipitates a prolonged process of immune activation and the development of a robust and durable immune response.

Immunotherapy is an emerging field of cancer treatment that aims to activate the immune system, as well as to overcome the immuno-suppressive mechanisms that cancer cells and their resulting tumors have developed. Approaches in immunotherapy generally have one of two desired effects on the immune system: “putting the foot on the gas,” which stimulates the immune system by therapies including vaccine-, cytokine-, antibody-, cellular- and adjuvant-based approaches; and “removing the brakes,” which removes the inhibition of the immune system, and currently mainly consists of monoclonal antibodies targeted against ligands and receptors that tumor cells use to suppress the immune system, such as PD-1, PD-L1 and CTLA-4. To date, these approaches have been demonstrated to activate the immune system to varying degrees, leading to anti-cancer benefits, but have often caused moderate to severe autoimmunity against healthy tissue, in many cases leading to discontinuation of treatment, persistent toxicity or even death.

Our Approach to Immunotherapy

Due to the novel mechanisms of action and favorable safety profile in clinical studies to date, we believe our RRVs represent an important advancement in the field of immunotherapy. Our approach is designed to enhance immune responses against cancer cells and, in the case of our lead product candidate, Toca 511 & Toca FC, reduce immune-suppressive myeloid cell inhibition of the immune system. Also, we believe our RRV platform has the potential to be safely combined with conventional therapies and complement emerging checkpoint inhibitors and other approaches to cancer immunotherapy.

Our RRV Platform

We have developed a first-in-class gene therapy platform, based on a genus of retroviruses called gamma retroviruses, designed to selectively deliver therapeutic genes to cancer cells. Native gamma-retroviruses, which were originally isolated from cancer cells, possess three useful properties as a gene therapy vector for human cancers: they have been demonstrated to be reasonably benign in primates; they only infect dividing cells and selectively infect cancer cells in vivo; and they have a small, simple genome structure that allows straightforward vector construction.

Our RRVs are not known human pathogens as they only exhibit minimal virulence gene activity. Virulence genes ordinarily result in widespread infection of healthy cells. Gamma retroviruses have evolved in a way that makes infection, replication and spread in immune deficient cancer cells more permissive than infection of healthy cells and tissues. Specifically, RRVs and their progeny do not directly kill the cells they infect during spread. Instead they bud from infected cells, which is less likely to stimulate an immune

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response to the virus. In contrast, oncolytic viral infection and cell lysis typically cause marked inflammation, leading to rapid viral clearance.

Although RRVs can spread in tumors, they usually cannot replicate and spread in healthy tissues in the body due to antiviral immune system activity. In healthy cells, gamma retroviruses are typically controlled by powerful cellular resistance factors whose production can be driven by Type 1 interferons, a subgroup of interferon proteins that help regulate the activity of the immune system to kill cancer cells and virally-infected cells. In contrast, cancer cells usually have defective Type 1 interferon signaling pathways, possibly from selective pressure from Type 1 interferons in the cancer microenvironment, potentially leading to lower levels of antiretroviral resistance factors. Our RRVs predominantly rely on immune deficiencies of cancer cells and tumors, combined with its non-inflammatory nature, to replicate and spread throughout the tumor and we believe have a good balance between attenuation and replication efficiency. In another mechanism of specificity, RRVs do not encode nuclear localization signals which, in certain viruses such as lentiviruses, facilitate virus entry into the nucleus of non-dividing cells to allow productive infection. Without nuclear localization signals, RRVs only enter the nuclei of dividing cells, such as cancer cells, during the time the nuclear membrane opens to create two daughter cells. Hence, RRVs have inherent selectivity to cancer and we have demonstrated this selectivity in vivo as shown below in a glioma growing in a mouse brain.

Further, in humans, as shown in the images below, in patients with HGG treated with Toca 511 and then Toca FC, in subsequently re-resected tumors, we confirmed the presence of CD protein (stained brown in left image) in tumor cells but not in nearby normal brain cells (stained blue in right image).

Our novel RRV platform is designed to be versatile. In preclinical testing, we have stably delivered several different therapeutic genes, and we can create new vectors using a well-defined process to insert one or more therapeutic genes into our RRVs. We have also engineered RRVs to enhance their suitability for therapeutic purposes. For example, we converted therapeutic genes of viral or fungal origin to use mammalian codons resulting in enhanced genomic stability as the RRV replicates and increased protein production in infected cells. We also modified the native vector by replacing the highly restrictive native envelope gene with a more permissive envelope gene which allows for entry of our RRV into most cancer cells through a widely available phosphate transport channel.  

In addition to developing our lead product candidate, Toca 511 & Toca FC, we are employing strategies to deliver genes which can reduce the production of specific proteins. For example, we built RRVs designed to inhibit the “brakes” on the immune system, from PD-1 and PD-L1 interaction, by inhibiting PD-L1 protein function in the cancer cells. Specifically, we have built RRVs with genes for anti-PD-L1 single chain antibodies and are evaluating them in our anti-PD-L1 preclinical program.

Our safety data with gamma retroviruses, preclinically and in humans, suggest that our RRV technology is worth exploring in combination with many conventional and newly developed cancer treatments.

Our Lead Product Candidate: Toca 511 & Toca FC

Our lead product candidate is a combination of an investigational biologic, Toca 511, and an investigational small molecule drug, Toca FC, designed to be used together. Toca 511 is a proprietary injectable RRV that encodes a prodrug activator enzyme, CD. CD is derived from yeast, and humans do not naturally have this gene. Its selective delivery to cancer cells means that the infected cancer cells selectively carry the CD gene and produce CD protein. Toca FC is an orally administered, proprietary extended-release version of 5-FC, a prodrug that is inactive as an anti-cancer drug. In humans, the orally administered Toca FC is absorbed and carried

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through the bloodstream, crosses the blood brain barrier and diffuses into the cancer cells. In animal models, we have shown that 5-FC is converted into the active anti-cancer drug, 5-FU, at high concentrations in Toca 511-infected cancer cells that are producing CD protein. 5-FU is a well-established anti-cancer agent that interferes with RNA and DNA metabolism and is used in many conventional chemotherapy settings.

Toca 511 contains an optimized yeast-derived CD gene downstream of structural RRV genes which code viral proteins (gag, pol, env). Regulatory genes flank the coding genes on either side.

In addition to the direct killing of Toca 511-infected cancer cells, 5-FU can kill neighboring uninfected cancer cells and immune-suppressive myeloid cells in the tumor. In our preclinical studies, following direct killing of these cells, our therapy activated the immune system against tumors. Toca 511 & Toca FC treatment is designed for cycles of sustained production of high levels of 5-FU directly in tumors, which we believe is important for robust and durable anti-cancer immune activation.

Toca 511 & Toca FC has a dual mechanism of action. Our treatment regimen is designed to transform tumors into chemotherapy factories of 5-FU, which kills infected cancer cells and neighboring dividing tumor cells, triggering activation of the immune system against tumor-associated antigens with systemic benefits. In humans, Toca 511 is administered by one of several routes and is allowed to selectively spread through the cancer cells for up to two months. After Toca 511 spreads, Toca FC is administered cyclically, for approximately one week of every four to eight weeks. In re-resected tumors from some patients in our trials, we observed CD protein in the tumor (by immunohistochemistry) but not in contiguous normal brain tissue. We also documented Toca 511 RNA and DNA, including the CD gene, selectively in the tumors. The CD protein produced in the tumor is designed to convert the 5-FC into 5-FU and achieve high intratumoral concentrations. As 5-FU is rapidly inactivated after diffusing from the tumor it has a short half- life and therefore low systemic activity and limited side effects.

Some patients, whose tumors appeared larger during serial MRI brain scans, had resections. In some of these cases, the re-resected tumor had large areas of necrosis, or tumor death, and dense lymphocytic infiltrates in some remaining areas of cancer, under higher magnification. Enlargement of a tumor during an inflammatory response as part of the killing process, is called pseudo-progression.

Through a combination of mechanisms and multiple cycles of tumor antigen presentation during Toca FC treatment cycles, tolerance to current and evolving cancer tumor-associated antigens is designed to be broken, leading to lymphocyte infiltration, immune activation, gradual killing and gradual shrinkage of the tumor, sometimes completely, over many months or years.

In summary, the CD gene we are delivering in our lead product candidate is designed to produce a unique protein which, in combination with oral Toca FC, generates high concentrations of an anti-cancer drug selectively in the tumor, leading to killing of cancer and immune suppressor cells and thereby activating the immune system against the cancer cells.

Clinical Development of Toca 511 & Toca FC

Toca 511 & Toca FC in Recurrent High Grade Glioma

Our initial proposed indication, recurrent HGG, also referred to as malignant glioma, is the most common and aggressive primary brain cancer and often strikes in the prime of life. The two most common forms of HGG are glioblastoma multiforme, or GBM, and anaplastic astrocytoma or AA, which are grade 4 and grade 3 tumors, respectively. The total number of new diagnoses of HGG expected in 2017 is about 180,000 worldwide and about 16,000 in the United States, with new diagnoses of GBM estimated to

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be approximately 12,500 in 2017 in the United States. Recurrent HGG represents a major unmet medical need. HGG recurs in most patients, even after maximal treatment.

Historical survival data for HGG trials is limited, though there are many published studies for GBM. Patients with newly diagnosed GBM who receive maximal therapy had a median survival of 14.6, 16.1 or 16.8 months according to three Phase 3 clinical trials published in the New England Journal of Medicine. Current standard of care therapy for patients with newly diagnosed GBM includes surgery, radiation therapy and chemotherapy, and is similar in all major markets. The Central Brain Tumor Registry of the United States reports the one-, five-, and 10-year survival rates for patients with GBM as 39.7%, 5.5%, and 2.9% from diagnosis respectively, making it one of the most lethal among all cancers.

Recurrent HGG is typically treated with oral chemotherapy drugs, such as lomustine or temozolomide, bevacizumab, radiation or further surgery with or without carmustine wafer (marketed as Gliadel wafer by Arbor Pharmaceuticals, LLC). Survival in our initial proposed indication, recurrent HGG, is shorter than newly diagnosed GBM with reported median overall survival approximately half of that in newly diagnosed patients. There are relatively few trials which report on recurrent HGG (inclusive of both grade 4 and 3). One trial published by Brem in The Lancet reported median overall survival of a carmustine wafer cohort to be 7.2 months. Reported median survival for patients in multicenter clinical trials with recurrent GBM ranges from 7.6 months, from a summary analysis of Phase 2 clinical trials conducted by the North American Brain Tumor Consortium, to 8.4 months, based on a weighted-average from recent lomustine trials. Clinical trials evaluating the anti-angiogenesis agent bevacizumab have shown median overall survival of 8.0 to 10.0 months in what we believe are particularly favorable patient groups because of the number of first recurrent patients and restrictions on tumor size. Neither surgery nor bevacizumab have been found to prolong survival of patients with recurrent GBM. Historically, partial response, or PR, (tumor shrinkage by 50%) rates for chemotherapy for recurrent HGG are low, typically ranging from 0% to 8.9%. Complete responses, or CR, (disappearance of the tumor) to chemotherapy are extremely rare, typically occurring in less than 1% of patients treated. We chose recurrent HGG as our initial proposed indication because of the significant unmet medical need, together with our goal to minimize time to regulatory approval.

Our ascending Phase 1 clinical trials and ongoing Phase 3 clinical trial are being conducted pursuant to an IND we submitted to the FDA in September 2009. This IND currently covers the indications of recurrent HGG, newly-diagnosed HGG and metastatic solid tumors. In the future, we may also focus on hematological malignancies.

Ascending Dose Phase 1 Clinical Trials

We have three ascending dose Phase 1 clinical trials in recurrent HGG with varying modes of delivery of the Toca 511 vector: injection into the cavity wall after surgical resection of the recurred tumor, direct transcranial intratumoral injection without resection, and intravenous administration followed, approximately one to two weeks later, by resection with further local vector delivery at the time of resection. These clinical trials of Toca 511 & Toca FC are in patients whose tumors have recurred following surgery, radiation therapy and chemotherapy. We have treated 127 recurrent HGG patients in these clinical trials in which we observed potential benefits, including extended overall survival and a favorable safety profile. The median overall survival of patients in the resection injection study exceeds historical controls across a variety of previously reported clinical trials and shows a trend towards a dose response. Furthermore, an independent radiology review, or IRR, identified tumor shrinkage in some patients, including several complete and partial responses.

The primary goal of these three Phase 1 clinical trials was to evaluate the safety and tolerability of Toca 511 & Toca FC. Although all trials were designed to identify the highest safe and well-tolerated dose of Toca 511 & Toca FC, called the maximum tolerated dose, criteria for dose-limiting toxicities were never reached. The most common adverse events associated with Toca 511 are fatigue, headache, and convulsion. For Toca FC, the most common treatment related adverse events are fatigue, diarrhea and nausea. The majority of toxicities are Grades 1-2. The maximum feasible dose of Toca 511 & Toca FC was determined, allowing us to move forward to our Phase 3 clinical trial. The maximum feasible dose of Toca 511 was chosen to be 4 mL delivered by forty 0.1 mL injections with a blunt tip, narrow bore needle and a side port for infusion, which is the highest practical number of injections which can be administered at the time of resection. The secondary goal of each of these three Phase 1 clinical trials is to evaluate the efficacy of Toca 511 & Toca FC, including tumor response observed by MRI and patient survival. These clinical trials also allow us to evaluate the presence of Toca 511 in tumors and tumor pathology at subsequent resection and to measure CD4 and CD8 T cell levels before and following treatment. In addition, we are conducting a continuation trial to follow long term safety and survival in patients from all three of these clinical trials.

Resection Injection Trial

In February 2012, we initiated a Phase 1 multicenter ascending dose clinical trial of Toca 511 & Toca FC in patients with recurrent HGG who are suitable for resection. As of the data cutoff of August 2017, of the 56 patients enrolled in the ascending-dose resection injection Phase 1 trial, 53 were efficacy evaluable and of those a subset of 23 patients mirrors the entry criteria, clinical setting and dosing for patients in our Phase 3 clinical trial.

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In this trial, following tumor resection, Toca 511 was administered by multiple small injections directly into the mixture of brain and cancer tissue surrounding the resection cavity. These injections target the tumor which has been left behind after surgery since the infiltration of the cancer into functional brain regions precludes complete resection. Pursuant to the protocol, the patient begins a seven- to 14-day course of oral Toca FC five to eight weeks following the administration of Toca 511 and repeats this Toca FC cycle every four to eight weeks thereafter. When the recommended Phase 2 dose was determined, cohorts evaluating lomustine or bevacizumab combined with Toca 511 & Toca FC were enrolled to provide safety data for the use of Toca 511 & Toca FC treatment in combination with standard HGG treatment in patients who appeared to be progressing in the ongoing trials. To date, no safety issues have been observed in these expansion cohorts. This clinical trial has completed enrollment, with 56 patients. There were 53 efficacy evaluable patients who received both Toca 511 and Toca FC. Based upon a data cutoff of September 18, 2015, a manuscript was published in Science Translational Medicine (Cloughesy et al. 2016).

Of the 56 patients enrolled, 43 were evaluable for response with both IRR and clinical assessment performed. There were 23 patients of the 56 who would have met the entry criteria for the ongoing Phase 3 study. As shown in the table below, in these 23 patients with HGG first or second recurrence treated in the Higher Dose Cohort (as defined below), when compared with baseline MRIs taken just prior to the start of Toca FC dosing (four to eight weeks after surgery), five CRs were identified by an IRR, providing further support for Toca 511 & Toca FC efficacy. All of these patients were continuing to respond as of their last MRI review as of a data cutoff in August 2017 and only received Toca 511 and Toca FC cancer treatment after resection. The CRs were determined based on the Macdonald criteria, including, for CR, complete disappearance of all enhancing measurable and non-measurable tumor. Total clinical benefit includes CRs, PRs and stable disease, or SD. As shown in the table below, five of six responses occurred in patients treated in the Higher Dose Cohort, suggesting a potential dose-response effect. Specifically, in this Phase 1 dose escalation resection trial, across all cohorts, including combination cohorts, no responses were seen in the lowest three Toca 511 doses (1.4 x 10⁷, 3.8 x 10⁸ and 1.5 x 10⁸ Therapeutic Units, or TU). The next four dose increments, referred to as the Higher Dose Cohort, all had durable (defined as greater than 6 months) objective responses (4.8 x 10⁸ TU with two CRs; 1.2 or 1.5 x 10⁹ TU with three CRs; and 4.8 x 10⁹ TU with one CR). We selected to use the Toca 511 dose of ~1 x 10⁹ TU for the registration-directed Toca 5 clinical trial.

Resection Study: All Responses are in the Higher Dose Cohort

Seven medical centers participated in the resection study, six of which had a patient with an objective response identified by an IRR. Sites included large regional hospitals and academic centers.

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In the table below, clinical data for each of the 23 patients is represented by a blue bar, with the x-axis measuring months of survival. Change in patient tumor status (i.e., PD, SD, PR, or CR) are represented along the bar, with the status at the end representing “best response” during the treatment. The green stars indicate the six patients who remain alive at the latest data cutoff. The responses, which occur approximately six to 19 months after Toca 511 administration, are consistent with immunologic response and all responders who remain alive have received no therapy other than Toca 511 & Toca FC since enrolling in the trial. Median duration of response had not been reached after a median follow up of 35.7 months (range 14.1 to 44.9 months).

Resection Study: Long-Term Survival in Higher Dose Cohort

The median overall survival of patients in this resection injection study (in which an ascending range of doses of Toca 511 were injected into the wall of the resection cavity after resection of the tumor) exceeds historical controls across a variety of previously reported clinical trials. Forty-three patients had a median overall survival of 12.4 months that was approximately five months longer relative to a weighted-average of results from clinical trials of drugs used as standard of care for recurrent HGG, including 7.2 months in the active arm of a randomized surgical recurrent HGG trial for the carmustine wafer. In a subset of 30 patients in our resection injection trial who received higher doses of Toca 511, median overall survival was higher, 14.4 months. Furthermore, in the subset of 23 patients in this trial that mirror the entry criteria, clinical setting and dosing for patients in our Phase 3 clinical trial, median overall survival was 13.2 months, an approximate six-month improvement in median overall survival relative to a weighted average of clinical trials of drugs used as standard of care (lomustine or bevacizumab) for recurrent HGG. Finally, in our patients with recurrent GBM at first or second recurrence in our resection injection trial (27 patients), median overall survival was 13.6 months, comparing favorably to the median survival of 7.1 months in the external control study of recurrent GBM patients treated with lomustine. We saw a plateau of survival in the Higher Dose Cohort, with a 40% survival probability at two years (data cutoff of September 18, 2015). Data from our resection injection study was reported in Science Translational Medicine (Cloughesy et al. 2016).

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Adapted from Cloughesy TF et al. with data cutoff September 1, 2016.

Furthermore, an independent radiology review of MRI brain scans from our Phase 1 clinical trials identified tumor shrinkage in some patients, including several CRs. All patients in the resection injection trial with objective responses remain with durable response as of August 2017, for a median of 35.7 months, which represents approximately four times longer duration of response relative to responses from a clinical trial of lomustine which showed an estimated median duration of response of approximately six months (range of response duration was 2.79 to 9.62 months).

This survival data, evidence of tumor response, as well as a reported safety profile of mild and moderate toxicity, encouraged us to plan our registration-directed Toca 5 clinical trial of Toca 511 & Toca FC in this same setting, enrolling patients with recurrent HGG who were planning for further resection of their tumor. Also, we chose the resection setting for the Toca 5 clinical trial because we believe that resection of the bulk of the tumor and then injection into the residual tumor left behind in the cavity wall provides a longer opportunity for the treatment to activate the immune system against the growing tumor.

We also tested for changes in CD4 and CD8 T cells in blood during the study, allowing us to evaluate both the safety and activity of our treatment on the immune system. Average increases of 34.0% in total CD4 (p=0.019) and 12.4% in total CD8 (p=0.277) were observed between the visit prior to Toca FC administration and the end of study, suggesting immune activation after Toca 511 & Toca FC treatment (n=43). The p value is the probability that the difference between two data sets was due to chance. The smaller the p value, the more likely the differences are not due to chance alone. In general, if the p value is less than or equal to 0.05, the outcome is statistically significant. The FDA’s evidentiary standard of efficacy generally relies on a p value of less than or equal to 0.05. Supporting data was obtained from a subsequent cohort in this trial, and in this case, there were significant increases in activated CD8+ T cells (p=0.015) within the CD8 population from patients (n=6 patients, 39 samples) showing clinical benefit (SD, CR) between pre- and post-treatment measurements, but not from patients with progressive disease (n=7 patients, 48 samples). A sustained increase in activated CD4+ T cells (p=0.16) was also observed within the CD4 population from patients showing clinical benefit. In these examples, immune cell testing occurred at baseline and at time points after one or more cycles of Toca FC.

Resection Injection Trial Compared to Lomustine External Control

Patients with GBM at first and second recurrence in our resection injection trial (n=27) were compared to an external control of lomustine-treated patients from a previously-conducted non-surgical Phase 3 clinical trial (database for control arm obtained from the trial sponsor). Surgery is not known to prolong survival in recurrent GBM. Both our resection injection trial and the external control lomustine trial were reasonably contemporaneous (our trial: 2012-2015; lomustine trial: 2006-2010). The characteristics of the patients in these trials were comparable: the external control had a slightly younger population, more patients in first recurrence and a lower percentage of patients requiring corticosteroids at baseline; and our resection injection trial had a higher percentage of patients with a Karnofsky performance status score of 90-100. The Karnofsky score is a 0-100 scale generally used by physicians to quantify a cancer patient’s general well-being and activities of daily life; 100 is “perfect” health and 0 is death. The median overall survival for patients with first or second recurrent GBM in our resection injection trial was 13.6 months (95% CI 11.1, 20) compared to 7.1 months (95% CI 6.01, 8.80) for patients in the external control lomustine trial. The hazard ratio for overall survival was 0.45 (95% CI 0.27, 0.77; p=0.0028), meaning that with Toca 511 & Toca FC the risk of death was reduced by 55% compared to lomustine. Although the data is not generated from a single randomized trial, use of statistical analysis of the external comparison is only for the purpose of providing context to some of the data collected in our Phase 1 resection injection trial. In the overall survival setting, the hazard ratio is the ratio of the hazard rate (probability of dying during a certain unit time) between two groups. The separation of the survival curves was early and continued through 30 months with overall survival at six months of 96.0% vs. 61.8% (p<0.001). Lomustine is one of the active control treatments for our ongoing Phase 3 clinical trial.

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A circle denotes a censored survival event, meaning that the survival is counted up to this timepoint.

Patients treated with Toca 511 & Toca FC had far fewer grade ≥ 3 adverse events and a virtual absence of hematologic toxicity for patients relative to the lomustine external control, where grade ≥ 3 thrombocytopenia occurred in 23.8% and neutropenia occurred in 13.1% of lomustine patients.

Intratumoral Injection Trial

In August 2010, we initiated a Phase 1 multicenter ascending dose clinical trial of Toca 511 & Toca FC to be administered via intratumoral injection in patients with recurrent HGG. A total of 54 patients were enrolled and treated in this study.

Patients were treated in ascending dose cohorts using two different intratumoral delivery methods. The first method utilized a biopsy needle under stereotactic guidance to concentrate Toca 511 delivery to one location at the advancing edge of the tumor. The second method utilized intraoperative MRI, delivering Toca 511 spread mostly throughout the center of the tumor using convection enhanced delivery over several hours, referred to as non-biopsy needle. Pursuant to the protocol, the patient began a seven-day course of oral Toca FC four weeks following Toca 511 injection and repeats the cycle of Toca FC every five to seven weeks thereafter.

Delivery of Toca 511 with a biopsy needle in this trial showed a median overall survival of 13.8 months, while delivery via non-biopsy needle showed 9.2 months. Delivery with biopsy needle exceeded the range of 7.1 to 8.5 months, the survival data for currently-approved therapies discussed above. The benefit of biopsy needle delivery compared to non-biopsy needle delivery is statistically significant (p value = 0.0249; indicating that there is a 97.5% probability that the observations are not due to chance alone). In a multivariate analysis controlling for other prognostic factors such as number of recurrences and tumor grade, the delivery method remains statistically significant.

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The IRR results as of our data transfer in August 2017 revealed a clinical benefit rate of 32.1%, with 16 of 53 patients (30.2%) showing stable disease. Two patients with stable disease were shown to have an unconfirmed PR (50% tumor shrinkage without subsequent confirmation by MRI). One patient had a confirmed PR, with duration of 7.8 months.

Intravenous Administration Followed by Resection Injection Trial in 17 Patients

In February 2014, we initiated a Phase 1 multicenter ascending dose clinical trial in patients with recurrent HGG who are scheduled for resection. Toca 511 was administered initially intravenously on one, three or five consecutive days followed by resection of the tumor with further Toca 511 administration using multiple small injections directly into the mixture of brain and cancer tissue surrounding the resection cavity. Samples of the resected tumor were evaluated for evidence of the presence of Toca 511. Pursuant to the protocol, the patient began a seven day course of oral Toca FC five to seven weeks following the administration of Toca 511 at resection and repeats the cycle of Toca FC every three to five weeks thereafter.

Following the intravenous delivery of Toca 511, CD protein is detectable and quantifiable in resected HGG tumor tissue. Furthermore, the study shows that Toca 511 can infect and spread in “hot” and “cold” tumors with activity independent of high levels of immunosuppressive T cells in the tumor microenvironment. Median overall survival in the intravenous study was 13.6 months as of April 2017 data cut, consistent with other ascending dose studies (e.g. 14.4 months median overall survival in the resection study). Toca 511 & Toca FC appeared to be well-tolerated with few Grade ≥ 3 treatment-related adverse events. An independent radiology review showed one patient with complete radiologic disappearance of all lesions. The results of the intravenous study support evaluation of the regimen in other solid tumors.

Biomarkers

As part of our exploration of mutation profiles that may serve as a biomarker for patients with a higher likelihood of long-term benefit, we observed that objective responses occurred in patients with IDH1 mutant (mt) and IDH1 wild type (wt) tumors. Approximately 15% of the population with HGG is believed to have the IDH1 mutation. Across the Phase 1 clinical trial program, and as of August 2017, the three patients with known IDH1 mutations at first recurrence had CRs (two in the resection study and one patient in the intravenous study with a radiologic CR) and all these IDH1 mutation patients are alive (range of survival 12.2 to 35.3 months), suggesting a potential association of IDH1 mutation to survival.

Pooled Safety Data

Toca 511 & Toca FC has been well tolerated in clinical trials to date. There has been little difference in adverse events among the three Phase 1 clinical trials in recurrent HGG other than a few adverse events unrelated to Toca 511 in the post-operative period of the resection clinical trial. For this reason we chose to pool safety data across the three ascending Phase 1 clinical trials. As shown in the table below, in 127 patients who received Toca 511, treatment-related adverse events were reported in 32.3% of patients and these events were predominantly low grade (25.2%). The most common treatment-related adverse events were fatigue (11.8%), headache (5.5%) and convulsion (4.7%). Also shown below, in 122 patients who received Toca FC, treatment-related adverse events were reported in 44.3% of patients and these events were predominantly low grade (41.0%). The most common treatment-related adverse events were fatigue (22.1%), diarrhea (13.9%), and nausea (9.8%). Treatment-related serious adverse events were reported in 6.3% of patients treated with Toca 511 and 2.4% of patients treated with Toca FC (which included pulmonary embolism, diarrhea and intracranial hemorrhage). Hematologic toxicity was infrequent and also low grade. We monitored blood samples for viral RNA and DNA and found that quantitative levels were cleared within two weeks to four months of administration. Also, we analyzed tumor and blood samples for viral insertion sites and demonstrated an absence of clonality, supporting viral safety. We also monitor Toca FC blood levels for the first treatment cycle and whenever the dose is increased. This helps us to adjust dosing upwards in patients with Toca FC blood levels below the target range. The favorable toxicity profile of Toca 511 & Toca FC suggests that combination with other modalities such as chemotherapy or radiation should yield little incremental toxicity.

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Adverse Events Related to Toca 511 and Toca FC – Pooled Across Studies

Ongoing Phase 3 Clinical Trial

In November 2015, we initiated the Phase 2 portion of a randomized, controlled Phase 2/3 clinical trial of Toca 511 & Toca FC against the current standard of care in recurrent HGG. In this clinical trial we are using doses of Toca 511 and Toca FC of 4 mL and 220 mg/kg/day, respectively, equivalent to the doses used in the Higher Dose Cohort of our Phase 1 resection injection trial. Enrollment criteria for patients in this clinical trial includes first or second recurrence of HGG, no prior treatment with bevacizumab for recurrent HGG, and a tumor size of less than or equal to five centimeters. We completed enrollment with 187 patients in the Phase 2 portion of this trial as of February 2017. Investigators may choose chemotherapy (lomustine or temozolomide) or antiangiogenic therapy (bevacizumab) for the control arm. We expect that the arms of the trial will be comparable through stratification at the time of 1:1 randomization based on performance status, geographic region and IDH1 mutation status. The primary endpoint for the trial is overall survival. The expected median overall survival for the control arm is 8.5 months based on the assumption that approximately 25% of patients will receive bevacizumab and the remainder will receive chemotherapy in the control arm. In this trial we are evaluating evidence for immunologic mechanisms of disease control and we will perform a detailed molecular analysis of RNA expression, IDH phenotypes and MGMT methylation status in resected tumors. We will continue to monitor blood for viral RNA, DNA and for Toca FC levels. This clinical trial is being conducted in the United States, Canada, Israel and South Korea. The principal investigator in the United States is Timothy Cloughesy, M.D., director of the neuro-oncology program at the University of California, Los Angeles.

Because overall survival is the primary endpoint, we did not request a Special Protocol Assessment from the FDA. At our Type B meeting with the FDA in March 2015, we and the FDA discussed the design of the trial and we subsequently finalized the protocol based upon the FDA’s feedback. We also discussed the possibility of providing the data from the Phase 2 portion of this clinical trial to the FDA prior to initiation of the Phase 3 portion of the trial. The FDA indicated that they would be willing to meet with us in an end of Phase 2 meeting to review the data if the results appear compelling.

In February 2017, the FDA granted Toca 511 & Toca FC Breakthrough Therapy Designation for the treatment of recurrent HGG. In June 2017, the EMA granted Toca 511 PRIME Designation for the treatment of patients with glioma.

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Our PRIME and Breakthrough Therapy Designation application was based on data from three Phase 1 ascending-dose clinical trials involving 127 patients with recurrent brain cancer. The clinical data included results published in Science Translational Medicine, including safety data, patient survival data and data regarding durable, complete or partial tumor shrinkage as determined by independent radiology review. In addition, preclinical information was provided to the FDA supporting a novel immunological mechanism of action involving the depletion of immune-suppressive myeloid cells in the tumor microenvironment.

Breakthrough Therapy Designation indicates that preliminary clinical evidence demonstrates the drug may have substantial improvement on one or more clinically significant endpoints over available therapy. Breakthrough Therapy Designation intensifies FDA involvement to ensure an efficient drug development program and is an organizational commitment from the FDA to involve its senior managers.

In October 2017, based on our communications with the FDA under Breakthrough Therapy Designation, we modified the original two-step trial design (Phase 2 followed by Phase 3) into a seamless, Phase 3 pivotal trial, also known as the Toca 5 trial.

Intravenous Clinical Trial

In July 2016, we initiated a Phase 1b clinical trial in various types of metastatic solid cancer, including colorectal, pancreatic, breast, lung and melanoma to confirm the selective tumor transduction with the CD gene and CD protein expression following Toca 511 delivery already documented in HGG with intravenous delivery. New diagnoses of these cancers are estimated to exceed 700,000 per year in the United States and 5.4 million per year worldwide. In our metastatic cancer trial we plan to evaluate safety, presence of Toca 511 genes in tumors of patients with widely-disseminated disease, immunologic activity in blood and tumor such as changes in CD4, CD8 and immune-suppressive myeloid cells, and clinical activity such as tumor response and clinical benefit. We also plan, in this clinical trial, to evaluate Toca 511 & Toca FC in combination with one or more checkpoint inhibitors. Toca 511 will be administered by intravenous injection followed by (1) intratumoral injection following biopsy or (2) injection into the resection cavity wall following planned resection in the case of recurrent HGG or brain metastases.

Planned Clinical Trials

In 2018, we plan to advance our clinical development plan evaluating Toca 511 & Toca FC in patients with newly diagnosed HGG. The primary goals of this study will be to evaluate the safety and preliminary efficacy of Toca 511 delivered at the time of resection and Toca FC subsequently delivered in conjunction with radiation and temozolomide.

Preclinical Studies of Toca 511 and 5-FC

We believe our preclinical studies support the clinical development of Toca 511 & Toca FC in brain cancers both as a stand-alone regimen and in combination with current treatments. During preclinical testing of Toca 511 we observed that treatment with Toca 511 and 5-FC had two powerful mechanisms of action: direct killing of cancer cells and activation of the immune system against the cancer cells. 5-FC, which we use in our preclinical studies, is the active component of the Toca FC tablets we use in humans. 

Preclinical Studies in Other Cancer Types

Our pipeline of proprietary programs has the potential to be applicable to a wide variety of cancers. For example, we have demonstrated biodistribution, tumor shrinkage, and long-term survival in colorectal, breast and bladder cancers in preclinical studies, in addition to our brain cancer models with an RRV containing CD and 5-FC.

Based on preclinical data, we believe Toca 511 & Toca FC has the potential to be effective in treating most cancer types. First, most human cancer cell lines that have been tested are permissive for Toca 511 and sensitive to Toca 511 and 5-FC at clinically relevant concentrations of 5-FC. Also, we have conducted in vivo studies in numerous cancer types, and the studies show that Toca 511 spreads through tumors, including after intravenous infusions into animals with highly-metastatic cancers. For example, in a metastatic colorectal cancer model with numerous lesions in the liver (below left), an RRV containing the GFP gene shows that intravenous administration of RRV is selectively present in the tumor tissue and leaves normal liver uninfected. Tumor metastases are identified by luciferase-based bioluminescence which closely overlays with the location of RRV expressing GFP (below right).

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Images of same liver in colorectal cancer metastases model after intravenous RRV delivery

In this animal model, as in animals with the same colorectal cancer metastases (above) in the brain, Toca 511 and 5-FC caused tumor shrinkage, long-term survival and the generation of anti-tumor immunity sufficient to prevent re-challenge. The treated mice had an apparent 56% cure rate and such animals showed a dramatic decrease in the number of MDSCs in the tumor microenvironment and, overall, generated an anti-tumor immune response based on their ability to reject reimplanted tumors. Our treatment mechanism of action of immune activation against cancer is further supported by the ability to provide long-term survival to animals with cancer that receive lymphocytes from animals previously treated with Toca 511 and 5-FC.

We believe these cell culture and additional animal studies support the view that Toca 511 & Toca FC is generally active against cancer and drives our decision to evaluate this treatment against various types of cancers in clinical trials.

Manufacturing

Our lead product candidate, Toca 511 & Toca FC, consists of a biological component and a drug component, which are separately manufactured and are both covered by our proprietary intellectual property. The process for Toca 511 manufacturing and testing has been developed internally and we believe that the process itself and the expertise to design and implement this process as well as the testing are significant assets. The process and the vector composition are covered by patents, patent applications and trade secrets. The process for Toca FC (extended release 5-FC) was also designed internally. We rely on third-party contract manufacturing organizations, or CMOs, for both of these manufacturing processes to produce our final product for clinical use, as currently we do not own or operate manufacturing facilities. In addition we utilize contract testing organizations, or CTOs, for the establishment and performance of validated product release assays for Toca 511 & Toca FC material. For Toca FC and Toca 511, we require that our CMOs produce bulk drug substances and finished drug products compliant with current Good Manufacturing Practices, or cGMP, requirements and all other applicable laws and regulations. We plan to release material with appropriately qualified assays by our CTOs, who we require to operate under cGMP. We will retain final responsibility for product release and maintain an appropriate quality assurance capability to meet this need. We will continue to rely on CMOs and CTOs to manufacture and perform release testing, respectively, of our products for commercial sale. We maintain agreements with manufacturers and testing laboratories that include confidentiality and intellectual property provisions to protect our proprietary rights related to our product candidates and testing methods.

We use a viral producer cell line to create Toca 511 and currently rely on a sole-source CMO to manufacture Toca 511. We believe that our current manufacturing capacity for Toca 511 will be sufficient to support our ongoing and planned clinical trials. We plan to use this CMO for commercial manufacturing and plan to establish a second CMO to support our commercial supply needs.

Manufacturing for Toca FC generally encompasses both the chemical synthesis of the active pharmaceutical ingredient, or API, and its formulation and fill/finish of the final product. We currently utilize a single CMO in the United States for the production of the API and a single CMO for the manufacture of the final drug product tablets. We expect these preparations to supply sufficient Toca FC drug substance to complete the planned clinical trials. We believe we have the manufacturing capacity to supply the drug product tablets for our ongoing and planned clinical trials. We plan to use the current API and formulation CMOs for commercial supply.

We currently have no plans to build our own manufacturing capacity to manufacture Toca 511 or Toca FC.

License and Collaboration Agreements

Laboratory Services and License Agreement with Siemens

In November 2011, we entered into a laboratory services and license agreement with Siemens, which we amended in June 2015, pursuant to which we agreed to engage Siemens (i) to develop and perform certain in vitro diagnostic assays in connection with the

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cancer therapy trials of Toca 511 & Toca FC, (ii) concurrently and/or thereafter, to further develop, obtain FDA approval for, and perform one or more of such in vitro diagnostic assays as drug monitoring diagnostics for Toca 511 & Toca FC as Toca 511 & Toca FC receives marketing approval from the FDA, and (iii) following FDA approval of such in vitro diagnostic assay as a monitoring diagnostic, to perform such in vitro diagnostic monitoring assays as necessary in connection with post-marketing clinical trials of Toca 511 & Toca FC and, if appropriate, as commercial diagnostic tests. We granted Siemens the licensed intellectual property covered by the agreement on an exclusive and non-exclusive basis, depending on Siemens’ use of such intellectual property.

Under the terms of the agreement, Siemens paid us an initial upfront payment of $0.5 million. Additionally, beginning with the first commercial sale of a product that has received approval for clinical use under the agreement, Siemens will pay us a royalty in the 10-20 percent range of net assay revenue with respect to approved designated assay products and net sales revenue with respect to approved in vitro diagnostic products, until the fifth anniversary of such commercial sale, subject to certain reductions. Beginning with the first commercial sale of Toca 511 or Toca FC, we will pay a royalty to Siemens in the low single-digit percentage range on net product sales of Toca 511 & Toca FC for sales up to the mid-nine-digit dollar range per year, until the fifth anniversary of such commercial sale.

The term of this agreement will continue until the expiration of all payment obligations. The agreement provides that it may be terminated by either party upon written notice to the other party in the event of the other party’s material breach of the agreement if such breach remains uncured for 45 days, or in the event the other party files a voluntary petition in bankruptcy, is adjudicated as bankrupt or insolvent after all appeals are exhausted, makes a general assignment for the benefit of creditors or fails to discharge or have dismissed within 60 days an involuntary petition in bankruptcy filed against it. If market approval is rejected by the FDA, Siemens must provide us with prompt written notice. Should the parties be unable to reach mutual agreement regarding regulatory strategy within 20 business days of such notice, then either party may terminate the agreement upon written notice to the other party. Siemens may terminate the agreement for any reason upon 90 days prior written notice to us, provided that, notwithstanding such termination, Siemens must continue to provide the laboratory services for any of our trials the protocol for which has been submitted to FDA until the conclusion of such pre-approval trial. Siemens may also terminate the agreement if, after using commercially reasonable efforts, certain assay specifications are not achieved. If Siemens terminates the agreement for breach of contract by us, the licenses granted to Siemens will survive such termination and will become non-exclusive, perpetual and irrevocable, provided that Siemens will have the right to terminate any such license at any time upon written notice to us. If the agreement expires, or if the agreement is terminated by us for breach of contract by Siemens or for failure to reach an agreement on regulatory strategy, the restriction in the license granted to activities outside of the territory will terminate, and we will have the right to pursue development and commercialization of companion diagnostics for products with one or more other partners in the territory, and to grant to such other partners sublicenses of our rights under the agreement. If the agreement is terminated by either party for failure to reach an agreement on regulatory strategy, or by Siemens by 90 days written notice, for a minimum of 45 days after the later of (i) the termination date or (ii) completion of any required post-termination laboratory services and delivery to us of all results thereof, Siemens must retain any stocks of qualified reagents for the assays that remain as of Siemens’ completion of such laboratory services, and, upon our request made at any time during such 45-day period, Siemens must deliver such remaining stocks to us, provided that we shall have executed documentation reasonably satisfactory to Siemens acknowledging that the use of such reagents is restricted to investigational use pursuant to our IND, and any other use permitted by, and in compliance with, applicable laws, regulatory guidelines and regulatory approvals.

License Agreement with USC

In October 2007, we entered into a license agreement with the University of Southern California, or USC, pursuant to which we received a worldwide, exclusive license to, among other things, manufacture and market products utilizing inventions related to our RRV platform and other key technology.

Under the terms of the agreement, we paid an initial license fee to USC in the low six-digit dollar range and issued to USC shares of our common stock in an amount equal to the low single-digit percent range of all the number of shares of common stock issued at the time shares were issued to our six founders prior to the date of the agreement. Pursuant to the agreement, we owe USC a royalty in the low single-digit percent range of our and our sub-licensee’s net sales of products covered by the agreement. In addition, we owe USC an additional royalty in the low single-digit percent range of revenue from our sub-licensees. Once our and our sub-licensees net sales reach an amount in the mid-seven digit dollar range, the minimum annual royalty payment due to USC will be in the low six-digit dollar range. Our royalty obligations continue on a licensed product-by-licensed product and country-by-country basis until the expiration of the last valid claim in the licensed patent covering a licensed product in such country.

The term of this agreement will continue until all of our royalty payment obligations have expired unless terminated earlier. The agreement provides that it may be terminated by either party upon written notice to the other party in the event of the other party’s material breach of the agreement if such breach remains uncured for 45 days. We may terminate the agreement without cause upon 45 days’ advance written notice to USC. USC may also terminate the agreement upon notice to us upon (i) the declaration by a court of competent jurisdiction that we are bankrupt and our assets are to be liquidated pursuant to the U.S. Bankruptcy Code; (ii) upon the filing or institution by us of bankruptcy, liquidation or receivership proceedings under Chapter 7 of the U.S. Bankruptcy Code;

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(iii) upon an assignment of a substantial portion of our assets for the benefit of creditors; or (iv) in the event a receiver or custodian is appointed in bankruptcy for all or substantially all of our business; provided, however, that in the case of any involuntary proceeding, such right to terminate shall only become effective if the proceeding is not dismissed within 120 days after the filing thereof. Upon termination of the agreement, all rights granted to or provided by each party to the other shall automatically and irrevocably revert to the granting party.

Grants

In August 2017, we were awarded a $2.0 million grant by the U.S. Food and Drug Administration Office of Orphan Products Development to support our Phase 3 clinical trial, or OOPD Grant. Under the grant agreement, we will be reimbursed for qualifying expenses over a four-year period subject to the availability of funds and satisfactory progress of the trial. At December 31, 2017, we had received $0.5 million relating to the OOPD Grant.

We have also received grants from the following entities: National Institutes of Health, Voices Against Brain Cancer, Musella Foundation, Accelerate Brain Cancer Cure, Inc., National Brain Tumor Society, American Brain Tumor Association, Adenoid Cystic Carcinoma Research Foundation, and Internal Revenue Service — Qualifying Therapeutic Discovery Project Program.

Sales and Marketing

We currently own exclusive worldwide development and commercial rights to our therapeutic product candidates and underlying viral technology platforms. We plan to build at the appropriate time a commercial infrastructure targeting oncologists, neuro-oncologists and neurosurgeons and related clinicians and health care workers in leading and regional cancer centers in the United States.

We anticipate that our commercial infrastructure will be built around a “high-touch” model to maximize patient access to our products. In addition to an internal team of dedicated medical sales, marketing, medical affairs, reimbursement, and commercial operations personnel we anticipate leveraging external capabilities such as contract pharmacy services. It is possible that a Risk Evaluation Mitigation Strategy program, or REMS, will be required for our products.

For our lead product candidate, Toca 511 & Toca FC for HGG, we have established a base of scientific familiarity with leading physicians in the United States, EU, Canada, South Korea, Israel and Japan. If we obtain regulatory approval, we expect that the base of familiarity we have built with leading international brain cancer centers during the conduct of our clinical trials, including the Toca 5 trial, will help drive market acceptance of our product. We believe that the majority of patients undergoing treatment for HGG in the United States are treated at approximately 60 brain cancer centers in the United States, many of which have participated in our clinical trials. Therefore, we believe a highly specialized, relatively small, medically-focused sales force, in addition to medical science liasons, will be sufficient to support the commercialization of our product.

Outside the United States, we may build our own commercial infrastructure or consider opportunities to enter into out-licensing or co-promotion agreements with other pharmaceutical or biotechnology companies to develop and/or commercialize our product candidates outside the United States.

We currently have very limited sales and marketing or distribution capabilities or in-house personnel specializing in these functions.

Intellectual Property

Intellectual property is of vital importance in our field and in biotechnology generally. We seek to protect and enhance proprietary technology, inventions, and improvements that are commercially important to the development of our business by seeking, maintaining, and defending patent rights, whether developed internally or licensed from third parties.

We will also seek to rely on regulatory protection afforded through Orphan-Drug Designations, data exclusivity, market exclusivity and patent term extensions where available.

We have obtained Orphan-Drug Designation for Toca 511 & Toca FC for the treatment of GBM, which makes the product eligible for a period of orphan drug exclusivity, if approved in this indication, under certain conditions. We believe that approval under a biologics license application, or BLA, will be eligible for 12 years of market exclusivity in the United States, 10 years of market exclusivity in Europe and significant durations in other markets, which would be complementary to any relevant patent exclusivity.

Through licensing and developing our own portfolio, and as of February 2018, we have rights to thirteen issued patents in the United States, seven of which are assigned to us and six of which are exclusively licensed to us, and 63 issued and granted patents in

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foreign countries, 45 of which are assigned to us and 18 of which are exclusively licensed to us, 11 patent applications in the United States, all of which are assigned to us and 61 patent applications in foreign countries, all of which are assigned to us. We believe that the issued patents will provide coverage on our technology platform and product candidates until approximately 2030. We file intellectual property we believe to be key to our business at a minimum in jurisdictions including the United States, Europe and Japan. Our original core technology was licensed from USC and The Regents of the University of California. Families within the portfolio are directed to our RRV technology platform, the modified CD gene that we use in Toca 511, various other therapeutic modalities and genes for use with RRV, manufacturing methods for RRV, the extended release Toca FC formulation, various combination therapies with Toca 511 & Toca FC and other agents, intravenous administration of RRV and diagnostic assays for detection of RRV.

We possess significant knowledge relating to the construction, manufacture, development and protection of gene therapy products. Certain intellectual property we aim to protect through a trade secret strategy.

Competition

The biotechnology and pharmaceutical industries, and the immunotherapy subsector, are characterized by rapid evolution of technologies, fierce competition and strong defense of intellectual property. A wide variety of institutions, including large pharmaceutical companies, specialty biotechnology companies, academic research departments and public and private research institutions are actively developing potentially competitive products and technologies. We face substantial competition from biotechnology and pharmaceutical companies developing products in immunotherapy and in our lead indication.

Companies developing other immunotherapy products generally fall within the following categories:

Approved treatments for HGG or GBM, a subset of HGG, include surgery, radiation and chemotherapy, the most widely used being temozolomide. Other approved treatments include the carmustine implant (marketed as Gliadel wafer by Arbor Pharmaceuticals, LLC), bevacizumab (marketed as Avastin by Genentech, Inc.), and NovoCure Limited’s personal electric field device, marketed as Optune (approved for the treatment of GBM). In addition to approved therapies, we expect that Toca 511 & Toca FC will compete with product candidates that we are aware of in clinical development by third parties, including nivolumab and ipilimumab (being developed as monocolonal antibodies targeting immune checkpoints, PD-1 and CTLA-4, for the treatment of GBM by Bristol-Myers Squibb Co.; currently in Phase 3 clinical trials), pembrolizumab (being developed as a monocolonal antibody targeting PD-1 for the treatment of GBM by Merck & Co., Inc.; currently in Phase 2 clinical trials), ABT414 (being developed as a monocolonal antibody targeting EGFR for the treatment of GBM by AbbVie Biotherapeutics Corporation; currently in Phase 2 clinical trials), VB-111 (being developed as an antiangiogenic agent delivered with adenovirus for recurrent GBM by Vascular Biogenics Ltd.; currently in Phase 3 clinical trials under a special protocol assessment), VAL-083 (a bi-functional alkylating agent in development for recurrent GBM by DelMar Pharmaceuticals Inc.; currently in Phase 1/2 clinical trials), TPI-207 (a 3 rd generation taxane in combination with bevacizumab in development for recurrent GBM by Cortice Biosciences; currently in Phase 1/2 clinical trials), martizomib (an alkylating proteasome inhibitor in development for GBM by Celgene Corporation in collaboration with Triphase Accelerator Corporation; currently in Phase 1 clinical trials), Ad-RTS-HIL-12 with veledimex in development for recurrent GBM by Ziopharm Oncology Inc.; currently in Phase 1 clinical trials, SL-701 (a GBM vaccine in development by Stemline Therapeutics Inc.; currently in Phase 2 clinical trials), PVSRIPO (a modified oncolytic polio virus being developed by Istari Oncology, Inc.), and a CAR T cells (being studied in Phase 1 clinical trials by University of Pennsylvania and City of Hope against EGFRvIII and interleukin-13 receptor alpha 2, respectively).

Any product candidates that we successfully develop and commercialize may compete with existing and new therapies that may become available in the future. The availability of reimbursement from government and other third-party payers will also significantly affect the pricing and competitiveness of our products.

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Many of our competitors, either alone or with strategic partners, have substantially greater financial, technical and human resources than we do. Accordingly, our competitors may be more successful than we are in obtaining approval for treatments and achieving widespread market acceptance, rendering our treatments obsolete or non-competitive. Accelerated mergers and acquisitions activity in the biotechnology and pharmaceutical industries may result in even more resources being concentrated among a smaller number of our competitors. These companies also compete with us in recruiting and retaining qualified scientific and management personnel, establishing clinical trial sites and patient registration for clinical trials and acquiring technologies complementary to, or necessary for, our programs. Smaller or early-stage companies may also prove to be significant competitors, particularly through collaborative arrangements with large and established companies.

Our commercial opportunity could be substantially limited in the event that our competitors develop and commercialize products that are more effective, safer, less toxic, more convenient or cheaper than our comparable products. In geographies that are critical to our commercial success, competitors may also obtain regulatory approvals before us, resulting in our competitors building a strong market position in advance of our product’s entry. We believe the competitive factors that will determine the success of our programs will be the efficacy, safety, pricing and reimbursement, and convenience of our product candidates.

Government Regulation

Our most advanced product candidate, Toca 511 & Toca FC, is subject to regulation as a combination product in the U.S., which means that it is comprised of both a drug product and a biologic product. If marketed individually, each component would be subject to different regulatory pathways and reviewed by different Centers within the FDA. A combination product, however, is assigned to a Center that will have primary jurisdiction over its regulation based on a determination of the combination product’s primary mode of action, which is the single mode of action that provides the most important therapeutic action. In the case of our Toca 511 & Toca FC product candidate, we believe that the primary mode of action is attributable to the biologic component of the product, which means that the Food and Drug Administration’s Center for Biologics Evaluation and Research, or CBER, has primary jurisdiction over premarket development. We have had formal communication with the Center for Drug Evaluation and Research, or CDER, acknowledging that CBER will be the lead review agency while CDER will be a consulting agency for the Toca FC product component. Accordingly, we are investigating Toca 511 & Toca FC pursuant to a single IND and we plan to seek approval of the combination product through a single BLA. Based on our discussions with the FDA to date, we do not anticipate that the FDA will require a separate marketing authorization for Toca FC, the small molecule drug component of the combination.

Combination products comprised of biological products, such as gene therapy products, and small molecule drugs, are subject to regulation under the Federal Food, Drug, and Cosmetic Act, or FD&C Act, and the Public Health Service Act, or PHS Act, and other federal, state, local, and foreign statutes and regulations. Both the FD&C Act and the PHS Act and their corresponding regulations govern, among other things, the testing, manufacturing, safety, efficacy, labeling, packaging, storage, record keeping, distribution, reporting, advertising, and other promotional practices involving combination products. In the United States, before clinical testing of such combination products, we must submit an IND to the FDA, which reviews the clinical protocol, and the IND must become effective before clinical studies may begin. In some instances, we must also submit our protocols to the U.S. National Institutes of Health, or NIH, through its Recombinant DNA Advisory Committee, or RAC, before initiating clinical testing of gene therapy products. FDA approval also must be obtained before marketing of combination products. The process of obtaining regulatory approvals and the subsequent compliance with appropriate federal, state, local, and foreign statutes and regulations require the expenditure of substantial time and financial resources.

Within the FDA, CBER regulates gene therapy products. CBER works closely with the NIH and its RAC, which makes recommendations to the NIH on gene therapy issues and engages in a public discussion of scientific, safety, ethical and societal issues related to proposed and ongoing gene therapy protocols. The FDA and the NIH have published guidance documents with respect to the development and submission of gene therapy protocols, including informed consent documents. The FDA also has published guidance documents related to, among other things, gene therapy products in general, their preclinical assessment, observing patients involved in gene therapy studies for delayed adverse events, potency testing, and chemistry, manufacturing and control information in gene therapy INDs.

Ethical, social, and legal concerns about gene therapy, genetic testing, and genetic research could result in additional regulations restricting or prohibiting the processes we may use. Federal and state agencies, congressional committees and foreign governments have expressed interest in further regulating biotechnology. More restrictive regulations or claims that our products are unsafe or pose a hazard could prevent us from commercializing any products. New government requirements may be established that could delay or prevent regulatory approval of our product candidates under development. It is impossible to predict whether legislative changes will be enacted, regulations, policies, or guidance changed, or interpretations by agencies or courts changed, or what the impact of such changes, if any, may be.

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U.S. Combination Products Development Process

The process required by the FDA before a biological product, including our Toca 511 & Toca FC combination product candidate, may be marketed in the United States generally involves the following:

Before testing any product candidate, including a gene therapy product, in humans, the product candidate enters the preclinical testing stage. Preclinical tests, also referred to as nonclinical studies, include laboratory evaluations of product chemistry, toxicity and formulation, as well as animal studies to assess the potential safety and activity of the product candidate. The conduct of certain preclinical tests must comply with federal regulations and requirements including GLPs.

Where a gene therapy study is conducted at, or sponsored by, institutions receiving NIH funding for recombinant DNA research, a protocol and related documentation has to be submitted to and the clinical trial registered with the NIH Office of Biotechnology Activities, or OBA, pursuant to the NIH Guidelines for Research Involving Recombinant DNA Molecules, or NIH Guidelines. Compliance with the NIH Guidelines is mandatory for investigators at institutions receiving NIH funds for research involving recombinant DNA, however many companies and other institutions not otherwise subject to the NIH Guidelines voluntarily follow them. The NIH is responsible for convening the RAC, a federal advisory committee, which discusses protocols that raise novel or particularly important scientific, safety or ethical considerations at one of its quarterly public meetings. Current NIH guidelines specify that RAC review of human gene transfer protocols should be limited to cases in which an oversight body, such as an Institutional Biosafety Committee or an Institutional Review Board, or IRB, determines that a protocol would significantly benefit from RAC review, and has been determined to meet certain additional criteria. The OBA will notify the FDA and the sponsor of the RAC’s decision regarding the necessity for full public review of a gene therapy protocol. RAC proceedings and reports are posted to the OBA web site and may be accessed by the public.

The clinical trial sponsor must submit the results of the preclinical tests, together with manufacturing information, analytical data, any available clinical data or literature and a proposed clinical protocol, to the FDA as part of the IND. Some preclinical testing may continue even after the IND is submitted. The IND automatically becomes effective 30 days after receipt by the FDA, unless the FDA places the clinical trial on a clinical hold within that 30-day time period. In such a case, the IND sponsor and the FDA must resolve any outstanding concerns before the clinical trial can begin. With gene therapy protocols, if the FDA allows the IND to proceed, but the RAC decides that full public review of the protocol is warranted, the FDA will request at the completion of its IND review that sponsors delay initiation of the protocol until after completion of the RAC review process. The FDA may also impose clinical holds on a product candidate at any time before or during clinical trials due to safety concerns or non-compliance. If the FDA imposes a clinical hold, trials may not recommence without FDA authorization and then only under terms authorized by the FDA. Accordingly, we cannot be sure that submission of an IND will result in the FDA allowing clinical trials to begin, or that, once begun, issues will not arise that suspend or terminate such trials.

Clinical trials involve the administration of the product candidate to healthy volunteers or patients under the supervision of qualified investigators, generally physicians not employed by or under the clinical trial sponsor’s control. Clinical trials are conducted under protocols detailing, among other things, the objectives of the clinical trial, dosing procedures, patient selection and exclusion criteria, and the parameters to be used to monitor patient safety, including stopping rules that assure a clinical trial will be stopped if certain adverse events should occur. Each protocol and any amendments to the protocol must be submitted to the FDA as part of the IND. Clinical trials must be conducted and monitored in accordance with the FDA’s regulations comprising the GCP requirements, including the requirement that all patients provide informed consent. Further, each clinical trial must be reviewed and approved by an independent IRB at or servicing each institution at which the clinical trial will be conducted. An IRB is charged with protecting the welfare and rights of clinical trial participants and considers such items as whether the risks to individuals participating in the clinical

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trials are minimized and are reasonable in relation to anticipated benefits. The IRB also approves the form and content of the informed consent, which must be signed by each clinical trial patient or his or her legal representative, and must monitor the clinical trial until completed. Clinical trials involving biological product candidates also must be reviewed by an institutional biosafety committee, or IBC, a local institutional committee that reviews and oversees basic and clinical research conducted at that institution. The IBC assesses the safety of the research and identifies any potential risk to public health or the environment.

Human clinical trials are typically conducted in three sequential phases that may overlap or be combined:

Post-approval clinical trials, sometimes referred to as Phase 4 clinical trials, may be conducted after initial marketing approval. These clinical trials are used to gain additional experience from the treatment of patients in the intended therapeutic indication, particularly for long-term safety follow-up. The FDA recommends that sponsors observe patients for potential gene therapy-related delayed adverse events with agents such as those we are developing for a period of up to 15 years, including a minimum of five years of annual examinations followed by ten years of annual queries, either in person or by questionnaire, of clinical trial patients.

During all phases of clinical development, regulatory agencies require extensive monitoring and auditing of all clinical activities, clinical data, and clinical trial investigators. Annual progress reports detailing the results of the clinical trials must be submitted to the FDA. Written IND safety reports must be promptly submitted to the FDA, the NIH and the investigators for serious and unexpected adverse events, any findings from other trials, tests in laboratory animals or in vitro testing that suggest a significant risk for human patients, or any clinically important increase in the rate of a serious suspected adverse reaction over that listed in the protocol or investigator brochure. The sponsor must submit an IND safety report within 15 calendar days after the sponsor determines that the information qualifies for expedited reporting. The sponsor also must notify the FDA of any unexpected fatal or life-threatening suspected adverse reaction within seven calendar days after the sponsor’s initial receipt of the information. Phase 1, Phase 2, and Phase 3 clinical trials may not be completed successfully within any specified period, if at all. The FDA, the sponsor, or its data safety monitoring board may suspend a clinical trial at any time on various grounds, including a finding that the patients are being exposed to an unacceptable health risk. Similarly, an IRB can suspend or terminate approval of a clinical trial at its institution if the clinical trial is not being conducted in accordance with the IRB’s requirements or if the investigational product candidate has been associated with unexpected serious harm to patients.

There are also requirements governing the reporting of ongoing clinical trials and completed clinical trial results to public registries. Sponsors of clinical trials of FDA-regulated products, including biologics, are required to register and disclose certain clinical trial information, which is publicly available at www.clinicaltrials.gov. Information related to the product, patient population, phase of investigation, study sites and investigators, and other aspects of the clinical trial is then made public as part of the registration. Sponsors are also obligated to discuss the results of their clinical trials after completion. Disclosure of the results of these trials can be delayed until the new product or new indication being studied has been approved. The NIH and the FDA have a publicly accessible database, the Genetic Modification Clinical Research Information System, which includes information on gene therapy trials and serves as an electronic tool to facilitate the reporting and analysis of adverse events on these trials.

Concurrent with clinical trials, companies usually complete additional animal studies and also develop additional information about the physical characteristics of the components of a combination product as well as finalize processes for manufacturing the components in commercial quantities in accordance with cGMP requirements. To help reduce the risk of the introduction of adventitious agents with use of biological products, the PHS Act emphasizes the importance of manufacturing control for products whose attributes cannot be precisely defined. The manufacturing process must be capable of consistently producing quality batches of the product candidate and, among other things, the sponsor must develop methods for testing the identity, strength, quality, potency and purity of the final product. Additionally, appropriate packaging must be selected and tested and stability studies must be conducted to demonstrate that the components of a combination product candidate do not undergo unacceptable deterioration over their shelf life.

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U.S. Review and Approval Processes

After the completion of clinical trials of an investigational biologic product, FDA approval of a BLA must be obtained before commercial marketing of the product. The BLA must include results of product development, laboratory, and animal studies, human trials, information on the manufacture and composition of the product, proposed labeling and other relevant information. In addition, under the Pediatric Research Equity Act, or PREA, a BLA or supplement to a BLA must contain data to assess the safety and effectiveness of the combination product for the claimed indications in all relevant pediatric subpopulations and to support dosing and administration for each pediatric subpopulation for which the product is safe and effective. The FDA may grant deferrals for submission of data or full or partial waivers. Unless otherwise required by regulation, PREA does not apply to any product for an indication for which orphan Designation has been granted. Currently we have Orphan-Drug Designation for Toca 511 & Toca FC for the treatment of GBM. The testing and approval processes require substantial time and effort and there can be no assurance that the FDA will accept the BLA for filing and, even if filed, that any approval will be granted on a timely basis, if at all.

Under the Prescription Drug User Fee Act, or PDUFA, as amended, each BLA must be accompanied by a significant user fee. The FDA adjusts the PDUFA user fees on an annual basis. PDUFA also imposes annual program fees on prescription drugs or biologics. Fee waivers or reductions are available in certain circumstances, including a waiver of the application fee for the first application filed by a small business. Additionally, no user fees are assessed on BLAs for products designated as orphan drugs, unless the application also includes a non-orphan indication.

Within 60 days following submission of the application, the FDA reviews a BLA to determine if it is substantially complete before the agency accepts it for filing. The FDA may refuse to file any BLA that it deems incomplete or not properly reviewable at the time of submission and may request additional information. In this event, the BLA must be resubmitted with the additional information. The resubmitted application also is subject to an initial filing review before the FDA accepts it for filing. Once the submission is accepted for filing, the FDA begins an in-depth substantive review of the BLA. The FDA reviews the BLA to determine, among other things, whether the proposed product is safe and potent, or effective, for its intended use, and has an acceptable purity profile, and whether the product is being manufactured in accordance with cGMP to assure and preserve the product’s identity, safety, strength, quality, potency and purity. The FDA may refer applications for novel products or products that present difficult questions of safety or efficacy to an advisory committee, typically a panel that includes clinicians and other experts, for review, evaluation and a recommendation as to whether the application should be approved and under what conditions. The FDA is not bound by the recommendations of an advisory committee, but it considers such recommendations carefully when making decisions. During the product approval process, the FDA also will determine whether a REMS is necessary to assure the safe use of the product. If the FDA concludes that a REMS is needed, the sponsor of the BLA must submit a proposed REMS; the FDA will not approve the BLA without a REMS, if required.

Before approving a BLA, the FDA will inspect the facilities at which the product is manufactured. The FDA will not approve the product unless it determines that the manufacturing processes and facilities are in substantial compliance with cGMP requirements and adequate to assure consistent production of the product within required specifications. Additionally, before approving a BLA, the FDA will typically inspect one or more clinical sites, to assure that the clinical trials were conducted in compliance with GCP requirements. To assure cGMP, GLP and GCP compliance, an applicant must incur significant expenditure of time, money, and effort in the areas of training, record keeping, production, and quality control.

Notwithstanding the submission of relevant data and information, the FDA may ultimately decide that the BLA does not satisfy its regulatory criteria for approval and deny approval. Data obtained from clinical trials are not always conclusive and the FDA may interpret data differently from how we interpret the same data. If the agency decides not to approve the BLA in its present form, the FDA will issue a complete response letter that usually describes all of the specific deficiencies in the BLA identified by the FDA. The deficiencies identified may be minor, for example, requiring labeling changes, or major, for example, requiring additional clinical trials. Additionally, the complete response letter may include recommended actions that the applicant might take to place the application in a condition for approval. If a complete response letter is issued, the applicant may either resubmit the BLA, addressing all of the deficiencies identified in the letter, or withdraw the application.

If a product candidate receives regulatory approval, the approval may be significantly limited to specific diseases and dosages or the indications for use may otherwise be limited, which could restrict the commercial value of the product. Further, the FDA may require that certain contraindications, warnings, or precautions be included in the product labeling. The FDA may impose restrictions and conditions on product distribution, prescribing, or dispensing in the form of a REMS, or otherwise limit the scope of any approval. In addition, the FDA may require post marketing clinical trials, sometimes referred to as Phase 4 clinical trials, designed to assess further a biological product’s safety and effectiveness, and testing and surveillance programs to monitor the safety of approved products that have been commercialized.

One of the performance goals agreed to by the FDA under the PDUFA is to review 90% of original standard BLAs within 10 months of the 60 day filing date and 90% of original priority BLAs within six months of the 60 day filing date, whereupon a review decision is to be made. The FDA does not always meet its PDUFA goal dates for standard and priority BLAs and its review goals are

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subject to change from time to time. The review process and the PDUFA goal date may be extended by three months if the FDA requests or the BLA sponsor otherwise provides additional information or clarification regarding information already provided in the submission within the last three months before the PDUFA goal date.

Orphan-Drug Designation

Under the Orphan-Drug Act, the FDA may grant orphan designation to a drug or biological product intended to treat a rare disease or condition, which is generally a disease or condition that affects fewer than 200,000 individuals in the United States, or more than 200,000 individuals in the United States for which there is no reasonable expectation that the cost of developing and making a drug or biological product available in the United States for this type of disease or condition will be recovered from sales of the product. Orphan product designation must be requested before submitting a BLA. After the FDA grants orphan product designation, the identity of the therapeutic agent and its potential orphan use are disclosed publicly by the FDA. We have been granted Orphan-Drug Designation by the FDA for Toca 511 & Toca FC for the treatment of GBM, which is a subset of HGG, the indication that we are initially pursuing. Orphan product designation does not convey any advantage in or shorten the duration of the regulatory review and approval process. There can be no assurance that we will receive Orphan-Drug Designation for additional indications or for any additional product candidates.

If a product candidate that has orphan designation subsequently receives the first FDA approval for the disease or condition for which it has such designation, the product is entitled to orphan product exclusivity, which means that the FDA may not approve any other applications to market the same drug or biological product for the same indication for seven years, except in limited circumstances, such as a showing of clinical superiority to the product with orphan exclusivity. Competitors, however, may receive approval of different products for the indication for which the orphan product has exclusivity or obtain approval for the same product but for a different indication for which the orphan product has exclusivity. Orphan product exclusivity also could block the approval of one of our products for seven years if a competitor obtains approval of the same biological product as defined by the FDA or if our product candidate is determined to be contained within the competitor’s product for the same indication or disease. If a drug or biological product designated as an orphan product receives marketing approval for an indication broader than what is designated, it may not be entitled to orphan product exclusivity. The Committee of Orphan Medicinal Products of the EMA has designated both flucytosine and vocimagene amiretrorepvec as orphan medicinal products indicated for the treatment of glioma. Orphan designation provides for a full waiver of Scientific Advice/Protocol Assistance fees in conjunction with small-medium enterprise.  Also included is a waiver of the fee for a marketing authorization application, and a 10-year market exclusivity upon approval which protects from market competition for similar medicines with similar indications.

Expedited Development and Review Programs

The FDA has four programs in place intended to facilitate and expedite development and review of new drugs and biologics intended to address unmet medical needs in the treatment of serious or life-threatening conditions: Fast Track Designation, Breakthrough Therapy Designation, accelerated approval, and priority review designation.

The Fast Track program is intended to expedite or facilitate the process for reviewing a new product if it is intended for the treatment of a serious or life-threatening disease or condition, and it demonstrates the potential to address unmet medical needs for such a disease or condition. Fast Track Designation applies to the combination of the product and the specific indication for which it is being studied. The sponsor of a new drug or biologic may request the FDA to designate the drug or biologic as a Fast Track product at any time during the clinical development of the product. Unique to a Fast Track product, the FDA may consider for review sections of the marketing application on a rolling basis before the complete application is submitted, if the sponsor provides a schedule for the submission of the sections of the application, the FDA agrees to accept sections of the application and determines that the schedule is acceptable, and the sponsor pays any required user fees upon submission of the first section of the application. We have received Fast Track Designation of Toca 511 & Toca FC for the treatment of patients with recurrent HGG, to improve their overall survival.

A new product can receive Breakthrough Therapy Designation if it is intended, alone or in combination with one or more other drugs, to treat a serious or life-threatening disease or condition and preliminary clinical evidence indicates that it may demonstrate substantial improvement over existing therapies on one or more clinically significant endpoints, such as substantial treatment effects observed early in clinical development. A Breakthrough Therapy Designation conveys all of the features of Fast Track Designation in addition to more intensive FDA guidance on an efficient development program, organizational commitment involving senior managers, and eligibility for priority review. Specifically, FDA intends to expedite the development and review of a Breakthrough Therapy by, where appropriate, intensively involving senior managers and experienced review staff in a proactive collaborative, cross-disciplinary review. Where appropriate, FDA also intends to assign a cross-disciplinary project lead for the review team to facilitate an efficient review of the development program. The FDA notes that a compressed drug development program still must generate adequate data to demonstrate that the drug or biologic meets the statutory standard for approval. Omitting components of the development program that are necessary for such a determination can significantly delay, or even preclude, marketing approval.

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The FDA has granted Toca 511 & Toca FC Breakthrough Therapy Designation for the treatment of recurrent HGG. Our Breakthrough Therapy Designation application was based on data from three Phase 1 ascending-dose clinical trials involving 126 patients with recurrent brain cancer. The clinical data included results published in Science Translational Medicine, including safety data, patient survival data and data regarding durable, complete or partial tumor shrinkage as determined by independent radiology review. In addition, preclinical information was provided to the FDA supporting a novel immunological mechanism of action involving the depletion of immune-suppressive myeloid cells in the tumor microenvironment.

Breakthrough Therapy Designation indicates that preliminary clinical evidence demonstrates the drug may have substantial improvement on one or more clinically significant endpoints over available therapy. Breakthrough Therapy Designation intensifies FDA involvement to ensure an efficient drug development program and is an organizational commitment from the FDA to involve its senior managers. We have up to six months after receiving the Breakthrough Therapy Designation to request an Initial Comprehensive Multidisciplinary meeting to discuss the drug development program. This initial meeting is a Type B meeting, used to discuss the overarching, high-level plan for drug development. The discussion will include topics such as planned clinical trials and endpoints, any resizing or adaptations to the trials, plans for expediting the manufacturing development strategy and studies that potentially could be completed after approval. When Breakthrough Therapy Designation has been granted, the FDA is encouraged to meet regularly with the sponsor and subsequent meetings are considered Type B meetings and are established based on the needs of the program.

The FDA may grant Accelerated Approval to a product candidate for a serious or life-threatening condition upon a determination that the product candidate has an effect on a surrogate endpoint that is reasonably likely to predict clinical benefit, or an effect on a clinical endpoint that can be measured earlier than an effect on irreversible morbidity or mortality, that is reasonably likely to predict an effect on irreversible morbidity or mortality or other clinical benefit, taking into account the severity, rarity, or prevalence of the condition and the availability or lack of alternative treatments. Accelerated approval is usually contingent on a sponsor’s agreement to conduct adequate and well-controlled additional post-approval trials to verify and describe the product’s clinical benefit. In addition, the FDA currently requires as a condition for accelerated approval pre-approval of promotional materials, which could adversely impact the timing of the commercial launch of the product.

Fast Track Designation, Breakthrough Therapy Designation, PRIME Designation and accelerated approval do not change the standards for approval but may expedite the development process.

An application for a product candidate may be eligible to obtain Priority Review Designation if it is intended to treat a serious condition and, if approved, would provide a significant improvement in safety or effectiveness. The FDA will attempt to direct additional resources to the evaluation of an application for a new product designated for priority review in an effort to facilitate the review.  Priority Review Designation does not change the standards for approval but may expedite the review process.

Post-Approval Requirements

Maintaining post-approval compliance with applicable federal, state, and local statutes and regulations requires the expenditure of substantial time and financial resources. Rigorous and extensive FDA regulation of combination products continues after approval, particularly with respect to cGMP. We rely, and expect to continue to rely, on third parties for the production and distribution of clinical and commercial quantities of any products that we may commercialize. Manufacturers of our products are required to comply with applicable requirements in the cGMP regulations, including quality control and quality assurance and maintenance of records and documentation. Other post-approval requirements applicable to combination products include reporting of cGMP deviations that may affect the identity, potency, purity and overall safety of a distributed product, record-keeping requirements, reporting of adverse effects, reporting updated safety and efficacy information, and complying with electronic record and signature requirements. After a BLA is approved, the product also may be subject to official lot release. As part of the manufacturing process, the manufacturer is required to perform certain tests on each lot of the product before it is released for distribution. If the product is subject to official release by the FDA, the manufacturer submits samples of each lot of product to the FDA together with a release protocol showing a summary of the history of manufacture of the lot and the results of all of the manufacturer’s tests performed on the lot. The FDA also may perform certain confirmatory tests on lots of some products, such as viral vaccines, before releasing the lots for distribution by the manufacturer. In addition, the FDA conducts laboratory research related to the regulatory standards on the safety, purity, potency, and effectiveness of combination products.

We also must comply with the FDA’s advertising and promotion requirements, such as those related to direct-to-consumer advertising, the prohibition on promoting products for uses or in patient populations that are not described in the product’s approved labeling (known as “off-label use”), industry-sponsored scientific and educational activities, and promotional activities involving the internet. Discovery of previously unknown problems or the failure to comply with the applicable regulatory requirements may result in restrictions on the marketing of a product or withdrawal of the product from the market as well as possible civil or criminal sanctions. Failure to comply with the applicable U.S. requirements at any time during the product development process, approval process or after approval, may subject an applicant or manufacturer to administrative or judicial civil or criminal sanctions and adverse publicity. FDA sanctions could include refusal to approve pending applications, withdrawal of an approval, clinical hold, warning or untitled letters, product recalls, product seizures, total or partial suspension of production or distribution, injunctions, fines, refusals of

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government contracts, mandated corrective advertising or communications with doctors, debarment, restitution, disgorgement of profits, or civil or criminal penalties. Any agency or judicial enforcement action could have a material adverse effect on us.

Manufacturers and other entities involved in the manufacture and distribution of approved products are required to register the establishments where the approved products are made with the FDA and certain state agencies, and are subject to periodic unannounced inspections by the FDA and certain state agencies for compliance with cGMPs and other laws. Accordingly, manufacturers must continue to expend time, money, and effort in the area of production and quality control to maintain cGMP compliance. Discovery of problems with a product after approval may result in restrictions on a product, manufacturer, or holder of an approved BLA, including withdrawal of the product from the market. In addition, changes to the manufacturing process or facility generally require prior FDA approval before being implemented. Other types of changes to the approved product, such as adding new indications and additional labeling claims, are also subject to further FDA review and approval.

U.S. Patent Term Restoration

Depending upon the timing, duration, and specifics of the FDA approval of the use of our product candidates, some of our U.S. patents may be eligible for limited patent term extension under the Drug Price Competition and Patent Term Restoration Act of 1984, commonly referred to as the Hatch-Waxman Amendments. The Hatch-Waxman Amendments permit a patent restoration term of up to five years as compensation for patent term lost during product development and the FDA regulatory review process. However, patent term restoration cannot extend the remaining term of a patent beyond a total of 14 years from the product’s approval date. The patent term restoration period is generally one-half the time between the effective date of an IND and the submission date of a BLA plus the time between the submission date of a BLA and the approval of that application. Only one patent applicable to an approved biological product is eligible for the extension and the application for the extension must be submitted prior to the expiration of the patent. The U.S. Patent and Trademark Office, in consultation with the FDA, reviews and approves the application for any patent term extension or restoration. In the future, we may intend to apply for restoration of patent term for one of our currently owned or licensed patents to add patent life beyond its current expiration date, depending on the expected length of the clinical trials and other factors involved in the filing of the relevant BLA.

Biosimilars and Exclusivity

The Biologics Price Competition and Innovation Act, or BPCIA, created an abbreviated approval pathway for biological products shown to be highly similar to, or interchangeable with, an FDA-licensed reference biological product. As of December 2017 there have been nine biosimilar products approved by the FDA. Two biosimilars have been approved to treat cancer.

Biosimilarity, which requires that there be no clinically meaningful differences between the biological product and the reference product in terms of safety, purity, and potency, can be shown through analytical studies, animal studies, and a clinical study or studies. Interchangeability requires that a product is biosimilar to the reference product and the product must demonstrate that it can be expected to produce the same clinical results as the reference product in any given patient and, for products that are administered multiple times to an individual, the biologic and the reference biologic may be alternated or switched after one has been previously administered without increasing safety risks or risks of diminished efficacy relative to exclusive use of the reference biologic.

The BPCIA includes, among other provisions:

The BPCIA also establishes procedures for identifying and resolving patent disputes involving applications submitted under section 351(k) of the PHS Act.

A biological product can also obtain pediatric market exclusivity in the United States. Pediatric exclusivity, if granted, adds six months to existing exclusivity periods and patent terms. This six-month exclusivity, which runs from the end of other exclusivity protection or patent term, may be granted based on the voluntary completion of a pediatric clinical trial in accordance with an FDA-issued “Written Request” for such a clinical trial.

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Additional U.S. Regulation

In the United States, our activities are potentially subject to regulation by various federal, state and local authorities in addition to the FDA, including but not limited to, the Centers for Medicare and Medicaid Services, or CMS, other divisions of the U.S. Department of Health and Human Services, for instance the Office of Inspector General, the U.S. Department of Justice, or DOJ, and individual U.S. Attorney offices within the DOJ, and state and local governments. For example, among other things, our sales, marketing and scientific/educational grant programs must comply with the anti-fraud and abuse provisions of the Social Security Act, the false claims laws, the physician payment transparency laws, the privacy and security provisions of the Health Insurance Portability and Accountability Act, or HIPAA, as amended by the Health Information Technology for Economic and Clinical Health Act, or HITECH, and similar state laws, each as amended.

In addition to the foregoing, state and federal laws regarding environmental protection and hazardous substances, including the Occupational Safety and Health Act, the Resource Conservancy and Recovery Act and the Toxic Substances Control Act, may affect our business. These and other laws govern our use, handling and disposal of various biological, chemical, and radioactive substances used in, and wastes generated by, our operations. If our operations result in contamination of the environment or expose individuals to hazardous substances, we could be liable for damages and governmental fines. We believe that we are in material compliance with applicable environmental laws and that continued compliance therewith is unlikely to have a material adverse effect on our business. We cannot predict, however, how changes in these laws may affect our future operations.

Federal and State Fraud and Abuse Laws

In the United States, our current and future operations are subject to regulation by various federal, state and local authorities in addition to the FDA, including but not limited to, CMS, other divisions of the U.S. Department of Health and Human Services, for instance, the Office of Inspector General, DOJ, and individual U.S. Attorney offices within the DOJ, and state and local governments. These federal and state laws, which may not be applicable to us or our product candidates unless and until we obtain FDA marketing approval for any of our product candidates, include, among others, anti-kickback statutes, false claims statutes, transparency laws, privacy laws and regulation regarding providing drug samples, sales and marketing activities and our relationships with customers and payors as follows.

The federal Anti-Kickback Statute prohibits, among other things, individuals and entities from knowingly and willfully offering, paying, soliciting, or receiving any remuneration, directly or indirectly, overtly or covertly, to induce or in return for purchasing, leasing, recommending, ordering, or arranging for the purchase, lease, recommendation or order of any health care item or service reimbursable, in whole or in part, under Medicare, Medicaid, or other federally financed healthcare programs. This statute has been interpreted to apply to arrangements between pharmaceutical manufacturers on one hand and prescribers, purchasers, and formulary managers on the other. Although there are a number of statutory exemptions and regulatory safe harbors protecting certain common activities from prosecution, the exemptions and safe harbors are drawn narrowly, and practices that involve remuneration that may be alleged to be intended to induce prescribing, purchases, or recommendations may be subject to scrutiny if they do not qualify for an exemption or safe harbor. Additionally, the intent standard under the Anti-Kickback Statute was amended by the Patient Protection and Affordable Care Act, as amended by the Health Care and Education Reconciliation Act of 2010, or collectively, the Affordable Care Act, to a stricter standard such that a person or entity does not need to have actual knowledge of the statute or specific intent to violate it in order to have committed a violation. Further, the Affordable Care Act codified case law that a claim including items or services resulting from a violation of the federal Anti-Kickback Statute constitutes a false or fraudulent claim for purposes of the federal civil False Claims Act.

HIPAA created additional federal criminal statutes that prohibit, among other actions, knowingly and willfully executing, or attempting to execute, a scheme to defraud or to obtain, by means of false or fraudulent pretenses, representations or promises, any money or property owned by, or under the control or custody of, any healthcare benefit program, including private third-party payers, willfully obstructing a criminal investigation of a healthcare offense, and knowingly and willfully falsifying, concealing or covering up by trick, scheme or device, a material fact or making any materially false, fictitious or fraudulent statement in connection with the delivery of or payment for healthcare benefits, items or services. Similar to the federal Anti-Kickback Statute, a person or entity does not need to have actual knowledge of the statute or specific intent to violate it in order to have committed a violation.

Federal false claims and civil monetary penalties laws, including the federal civil False Claims Act, prohibit, among other things, any person or entity from knowingly presenting, or causing to be presented, a false, fictitious or fraudulent claim for payment to, or approval by, the federal government, or knowingly making, using, or causing to be made or used, a false statement to get a false claim paid. Several pharmaceutical and other health care companies have been prosecuted under these laws for allegedly providing free product to customers with the expectation that the customers would bill federal programs for the product. Other companies have been prosecuted for causing false claims to be submitted because of the company’s marketing of the product for unapproved, and thus non-reimbursable, uses.

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The majority of states also have statutes or regulations similar to the federal Anti-Kickback Statute and false claims laws, which apply to items and services, reimbursed under Medicaid and other state programs, or, in several states, apply regardless of the payer.

We may also be subject to data privacy and security regulations by both the federal government and the states in which we conduct our business. HIPAA, as amended by HITECH, and their respective implementing regulations, including the final Omnibus Rule published on January 25, 2013, imposes requirements on certain types of entities, including certain healthcare providers, health plans, and healthcare clearinghouses, such as mandatory contractual terms, relating to the privacy, security, and transmission of individually identifiable health information. Among other things, HITECH makes HIPAA’s security standards and certain privacy standards directly applicable to business associates, which are independent contractors or agents of covered entities that create, receive, maintain or transmit protected health information in connection with providing a service for or on behalf of a covered entity. HITECH also created four new tiers of civil monetary penalties, amended HIPAA to make civil and criminal penalties directly applicable to business associates, and gave state attorneys general new authority to file civil actions for damages or injunctions in federal courts to enforce the federal HIPAA laws and seek attorneys’ fees and costs associated with pursuing federal civil actions. In addition, many state laws govern the privacy and security of health information in specified circumstances, many of which differ from each other and from HIPAA in significant ways and may not have the same requirements, thus complicating compliance efforts.

Additionally, the federal Physician Payments Sunshine Act under the Affordable Care Act, and its implementing regulations, require that certain manufacturers of drugs, devices, biological and medical supplies for which payment is available under Medicare, Medicaid or the Children’s Health Insurance Program, with certain exceptions, annually report to CMS information related to certain payments or other transfers of value made or distributed to physicians and teaching hospitals, or to entities or individuals at the request of, or designated on behalf of, the physicians and teaching hospitals and to report annually certain ownership and investment interests held by physicians and their immediate family members.

Because of the breadth of these laws and the narrowness of the exceptions and safe harbors, it is possible that some of our business activities could be subject to challenge under one or more of such laws. Such a challenge could have a material adverse effect on our business, financial condition, and results of operations. If our operations are found to be in violation of any of these or any other health regulatory laws that may apply to us, we may be subject to, without limitation, significant penalties, including the imposition of significant civil, criminal and administrative penalties, damages, monetary fines, disgorgement, individual imprisonment, possible exclusion from participation in Medicare, Medicaid and other federal healthcare programs, contractual damages, reputational harm, diminished profits and future earnings, additional integrity oversight and reporting obligations and curtailment or restructuring of our operations, any of which could adversely affect our ability to operate our business and our results of operations.

In addition, as part of the sales and marketing process, pharmaceutical companies frequently provide samples of approved products to physicians. This practice is regulated by the FDA and other governmental authorities, including, in particular, requirements concerning record keeping and control procedures. Any failure to comply with the regulations may result in significant criminal and civil penalties as well as damage to our credibility in the marketplace.

Coverage and Reimbursement

In many of the markets where we may do business in the future, the prices of pharmaceutical products are subject to direct price controls (by law) and to reimbursement programs with varying price control mechanisms. In the United States, significant uncertainty exists as to the coverage and reimbursement status of any product candidates for which we obtain product approval. A number of gene therapy products have been approved over the past year by the FDA. Although CMS subsequently approved its first method of coverage and reimbursement for one such product, the methodology has been subject to challenge by members of Congress. Often private payers follow the coverage and reimbursement decisions of the Medicare program, and it is difficult to predict how CMS may decide to cover and reimburse our product candidates, once approved, and those determinations are subject to change.

Moreover, the process for determining whether a third-party payer will provide coverage for a drug product may be separate from the process for setting the price of a drug product or for establishing the reimbursement rate that such a payer will pay for the drug product. Third-party payers may limit coverage to specific products on an approved list, also known as a formulary, which might not include all of the FDA-approved drugs for a particular indication. A decision by a third-party payer not to cover our product candidates could reduce physician utilization of our products once approved. A payer’s decision to provide coverage for a drug product does not imply that an adequate reimbursement rate will be approved. Further, one payer’s determination to provide coverage for a drug product does not assure that other payers will also provide coverage for the drug product. Coverage and reimbursement for new products can differ significantly from payer to payer. As a result, the coverage determination process will require us to provide scientific and clinical support for the use of our products to each payer separately and will be a time-consuming process. Additionally, third-party reimbursement may not be available or may not be adequate to enable us to maintain price levels sufficient to realize an appropriate return on our investment in product development.

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We intend to seek approval to market our product candidates in both the United States and in selected foreign jurisdictions. If we obtain approval in one or more foreign jurisdictions for our product candidates, we will be subject to rules and regulations in those jurisdictions. In some foreign countries, particularly those in the European Union, the pricing of biologics is subject to governmental control and other market regulations which could put pressure on the pricing and usage of our product candidates. In these countries, pricing negotiations with governmental authorities can take considerable time after obtaining marketing approval of a product candidate.

The marketability of any product candidates for which we or our collaborators receive regulatory approval for commercial sale may suffer if the government and third-party payers fail to provide adequate coverage and reimbursement. In addition, an emphasis on cost containment measures in the United States has increased and we expect will continue to increase the pressure on pharmaceutical pricing. Third-party payers are increasingly challenging the prices charged for medical products and services, examining the medical necessity and reviewing the cost-effectiveness of drugs, medical devices and medical services, in addition to questioning safety and efficacy. If these third-party payers do not consider our products to be cost-effective compared to other available therapies, they may not cover our products after FDA approval or, if they do, the level of payment may not be sufficient to allow us to sell our products at a profit. Coverage policies and third-party reimbursement rates may change at any time. Even if favorable coverage and reimbursement status is attained for one or more products for which we or our collaborators receive regulatory approval, less favorable coverage policies and reimbursement rates may be implemented in the future.

Healthcare Reform

In March 2010, President Obama enacted the Affordable Care Act, which has the potential to substantially change healthcare financing and delivery by both governmental and private insurers, and significantly impact the pharmaceutical and biotechnology industry. The Affordable Care Act will impact existing government healthcare programs and may result in the development of new programs.

Among the Affordable Care Act’s provisions of importance to the pharmaceutical and biotechnology industries, in addition to those otherwise described above, are the following:

Since its enactment, there have been judicial and Congressional challenges to certain aspects of the Affordable Care Act, as well as recent efforts by the Trump administration to repeal or replace certain aspects of the Affordable Care Act. Since January 2017, President Trump has signed two Executive Orders and other directives designed to delay the implementation of certain provisions of

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the Affordable Care Act or otherwise circumvent some of the requirements for health insurance mandated by the Affordable Care Act. Concurrently, Congress has considered legislation that would repeal or repeal and replace all or part of the Affordable Care Act. While Congress has not passed comprehensive repeal legislation, two bills affecting the implementation of certain taxes under the Affordable Care Act have been signed into law. The Tax Cuts and Jobs Act of 2017 includes a provision repealing, effective January 1, 2019, the tax-based shared responsibility payment imposed by the Affordable Care Act on certain individuals who fail to maintain qualifying health coverage for all or part of a year that is commonly referred to as the “individual mandate”. Additionally, on January 22, 2018, President Trump signed a continuing resolution on appropriations for fiscal year 2018 that delayed the implementation of certain Affordable Care Act-mandated fees, including the so-called “Cadillac” tax on certain high cost employer-sponsored insurance plans, the annual fee imposed on certain health insurance providers based on market share, and the medical device excise tax on non-exempt medical devices. Further, the Bipartisan Budget Act of 2018, or the BBA, among other things, amends the Affordable Care Act, effective January 1, 2019, to close the coverage gap in most Medicare Part D drug plans, commonly referred to as the “donut hole”. We expect there will be additional challenges and amendments to the Affordable Care Act in the future as the Trump administration and the U.S. Congress will likely continue to seek to modify, repeal or otherwise invalidate all, or certain provisions of, the Affordable Care Act. It is uncertain the extent to which any such changes may impact our business or financial condition.

Other legislative changes have been proposed and adopted in the United States since the Affordable Care Act was enacted. For example, in August 2011, the Budget Control Act of 2011, among other things, created measures for spending reductions by Congress. A Joint Select Committee on Deficit Reduction, tasked with recommending a targeted deficit reduction of at least $1.2 trillion for the fiscal year 2012 through 2021, was unable to reach required goals, thereby triggering the legislation’s automatic reduction to several government programs. This includes aggregate reductions of Medicare payments to providers of up to 2% per fiscal year, which went into effect in April 2013 and, due to subsequent legislation, including the BBA, will remain in effect through 2027 unless additional Congressional action is taken. Further, in January 2013, President Obama signed into law the American Taxpayer Relief Act of 2012, which, among other things, further reduced Medicare payments to several providers, including hospitals, imaging centers and cancer treatment centers, and increased the statute of limitations period for the government to recover overpayments to providers from three to five years.

In addition, there has been heightened governmental scrutiny in the United States of pharmaceutical pricing practices in light of the rising cost of prescription drugs and biologics. Such scrutiny has resulted in several recent Congressional inquiries and proposed and enacted federal and state legislation designed to, among other things, bring more transparency to product pricing, review the relationship between pricing and manufacturer patient programs, and reform government program reimbursement methodologies for products. At the federal level, the Trump administration’s budget proposal for fiscal year 2019 contains further product price control measures that could be enacted during the 2019 budget process or in other future legislation, including, for example, measures to permit Medicare Part D plans to negotiate the price of certain products under Medicare Part B, to allow some states to negotiate product prices under Medicaid, and to eliminate cost sharing for generic products for low-income patients. While any proposed measures will require authorization through additional legislation to become effective, Congress and the Trump administration have each indicated that it will continue to seek new legislative and/or administrative measures to control drug costs. At the state level, legislatures are increasingly passing legislation and implementing regulations designed to control pharmaceutical and biological product pricing, including price or patient reimbursement constraints, discounts, restrictions on certain product access and marketing cost disclosure and transparency measures, and, in some cases, designed to encourage importation from other countries and bulk purchasing.

We anticipate that the Affordable Care Act and other legislative reforms will result in additional downward pressure on the price that we receive for any approved product, if covered, and could seriously harm our business. Any reduction in reimbursement from Medicare and other government programs may result in a similar reduction in payments from private payers. The implementation of cost containment measures or other healthcare reforms may prevent us from being able to generate revenue, attain profitability, or commercialize our products. In addition, it is possible that there will be further legislation or regulation that could harm our business, financial condition, and results of operations.

Environmental Regulation

In addition to the foregoing, state and federal laws regarding environmental protection and hazardous substances, including the Occupational Safety and Health Act, the Resource Conservancy and Recovery Act and the Toxic Substances Control Act, may affect our business. These and other laws govern our use, handling and disposal of various biological, chemical, and radioactive substances used in, and wastes generated by, our operations. If our operations result in contamination of the environment or expose individuals to hazardous substances, we could be liable for damages and governmental fines. We believe that we are in material compliance with applicable environmental laws and that continued compliance therewith is unlikely to have a material adverse effect on our business. We cannot predict, however, how changes in these laws may affect our future operations.

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U.S. Foreign Corrupt Practices Act

The U.S. Foreign Corrupt Practices Act, to which we are subject, prohibits corporations and individuals from engaging in certain activities to obtain or retain business or to influence a person working in an official capacity. It is illegal to pay, offer to pay or authorize the payment of anything of value to any foreign government official, government staff member, political party, or political candidate in an attempt to obtain or retain business or to influence otherwise a person working in an official capacity.

Government Regulation Outside of the United States

In addition to regulations in the United States, we will be subject to a variety of regulations in other jurisdictions governing, among other things, clinical trials and any commercial sales and distribution of our products. Because biologically sourced raw materials are subject to unique contamination risks, their use may be subjected to different types of restrictions in different countries.

Whether or not we obtain FDA approval for a product, we must obtain the required approvals from regulatory authorities in foreign countries prior to the commencement of clinical trials or marketing of the product in those countries. Certain countries outside of the United States have a similar process that requires the submission of a clinical trial application equivalent to an IND prior to the commencement of human clinical trials. In the European Union, for example, a clinical trial authorization, or CTA, must be submitted to each country’s national health authority and an independent ethics committee, much like the FDA and the IRB, respectively. Once the CTA is approved in accordance with a country’s requirements, clinical trials may start.

The requirements and process governing the conduct of clinical trials, product licensing, pricing, and reimbursement vary from country to country. In all cases, the clinical trials are to be conducted in accordance with GCP, applicable regulatory requirements, and the ethical principles that have their origin in the Declaration of Helsinki.

If we fail to comply with applicable foreign regulatory requirements, we may be subject to, among other things, fines, suspension, or withdrawal of regulatory approvals, product recalls, seizure of products, operating restrictions and criminal prosecution in those countries.

Research and Development

Our research and development expenses were $29.1 million, $27.2 million and $19.2 million for the years ended December 31, 2017, 2016 and 2015, respectively. Please see “Management’s Discussion and Analysis of Financial Condition and Results of Operations” in this Annual Report on Form 10-K for additional information related to research and development expenditures.

Employees

As of December 31, 2017, we had 67 full-time employees, 20 of whom have Ph.D. or M.D. degrees. Of these full-time employees, 54 employees are engaged in research and development activities and 13 employees are engaged in finance and general management activities including accounting, contracts, human resources, information technology, investor relations, marketing and business development. We have no collective bargaining agreements with our employees and we have not experienced any work stoppages. We consider our relations with our employees to be good. 

Geographic Information

During 2017, 2016 and 2015, all of our long-lived assets were located within the United States.

Corporate Information

We were incorporated in Delaware in August 2007. Our principal executive offices are located at 3030 Bunker Hill Street, Suite 230, San Diego, California 92109. Our telephone number is (858) 412-8400. Our website address is www.tocagen.com.

This Annual Report on Form 10-K, our Quarterly Reports on Form 10-Q, Current Reports on Form 8-K, and any amendments to those reports filed or furnished pursuant to Sections 13(a) and 15(d) of the Securities Exchange Act of 1934, as amended, or the Exchange Act, are available (free of charge) on our website as soon as reasonably practicable after we electronically file such material with, or furnish it to, the Securities and Exchange Commission, or SEC.

Information contained on, or that can be accessed through, our website or social medial sites does not constitute part of this Annual Report on Form 10-K or any other report or document we file with the SEC, and any references to our website and social media sites are intended to be inactive textual references only.

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Tocagen, the Tocagen logo and other trademarks or service marks of Tocagen are the property of Tocagen. Other service marks, trademarks, and tradenames referred to in this Annual Report on Form 10-K are the property of their respective owners. Except as set forth above and solely for convenience, the trademarks and tradenames in this Annual Report on Form 10-K are referred to without the ® and ™ symbols, but such references should not be construed as any indicator that their respective owners will not assert, to the fullest extent under applicable law, their rights thereto.

We are an “emerging growth company” as defined in the JOBS Act. We will remain an emerging growth company until the earliest of (i) the last day of our first fiscal year in which we have total annual gross revenues of $1 billion or more, (ii) the date on which we are deemed to be a “large accelerated filer” under the rules of the SEC with at least $700 million of outstanding equity securities held by non-affiliates, (iii) the date on which we issued more than $1 billion in non-convertible debt during the previous three years, or (iv) December 31, 2022. References herein to “emerging growth company” are intended to have the meaning associated with it in the JOBS Act.

Item 1A. Risk Factors.

You should carefully consider the following risk factors, as well as the other information in this report, before deciding whether to purchase, hold or sell shares of our common stock. The occurrence of any of the following risks could harm our business, financial condition, results of operations and/or growth prospects or cause our actual results to differ materially from those contained in forward-looking statements we have made in this report and those we may make from time to time. You should consider all of the factors described in this section as well as those discussed in “Management’s Discussion and Analysis of Financial Condition and Results of Operations” and our financial statements and the related notes when evaluating our business. If any of the following risks actually occurs, our business, financial condition, results of operations and future growth prospects would likely be materially and adversely affected. In these circumstances, the market price of our common stock would likely decline and you may lose all or part of your investments.  Additional risks and uncertainties not presently known to us or that we currently deem immaterial also may impair our business operations.

Risks related to our business and industry

We have incurred significant losses since our inception and anticipate that we will continue to incur significant losses for the foreseeable future.

We are a clinical-stage company with a limited operating history. We are not profitable and have incurred net losses in each year since our inception in 2007, including net losses of $38.9 million, $33.5 million and $23.1 million for the years ended December 31, 2017, 2016 and 2015, respectively. As of December 31, 2017, we had an accumulated deficit of $166.9 million.

We have devoted substantially all of our financial resources to research and development, including our clinical, preclinical and platform development activities. To date, we have financed our operations primarily through the private placement of our convertible preferred stock, our initial public offering of our common stock, the issuance of our notes payable and the issuance of convertible promissory notes. We expect to continue to incur significant expenses and increasing operating losses for the foreseeable future. The amount of our future net losses will depend, in part, on the rate of our future expenditures and our ability to generate revenue. We have not completed late-stage clinical trials for any product candidate and it will be several years, if ever, before we have a product candidate ready for regulatory approval and commercialization. Even if we succeed in obtaining regulatory approval and commercializing one or more of our product candidates, we will continue to incur substantial research and development and other expenditures to develop and market additional product candidates. We may encounter unforeseen expenses, difficulties, complications, delays and other unknown factors that may adversely affect our business. The size of our future net losses will depend, in part, on the rate of future growth of our expenses and our ability to generate revenue. Our prior losses and expected future losses have had and will continue to have an adverse effect on our stockholders’ equity and working capital.

We will require substantial additional financing to achieve our goals, which may not be available on acceptable terms, or at all. Failure to obtain this necessary capital when needed may force us to delay, limit or terminate our product development efforts or other operations.

We are currently advancing our lead product candidate, Toca 511 & Toca FC, through clinical development and other product candidates through preclinical development. Developing gene therapy products is expensive, and we expect our research and development expenses to increase substantially in connection with our ongoing activities, particularly as we advance our product candidates in clinical trials.

As of December 31, 2017, our cash, cash equivalents and marketable securities were $88.7 million. We expect that our existing cash, cash equivalents and marketable securities as of December 31, 2017 will be sufficient to fund our current operations through at least the next 12 months. However, our operating plan may change as a result of many factors currently unknown to us, and we may need to seek additional funds sooner than planned, through equity and/or debt financings. We do not have any committed external

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source of funds. We may also consider new collaborations or selectively partner our technology or programs. In any event, we will require additional capital to obtain regulatory approval for, and to commercialize, our product candidates. Raising funds in the current economic environment may present additional challenges. Even if we believe we have sufficient funds for our current or future operating plans, we may seek additional capital if market conditions are favorable or if we have specific strategic considerations.

Any additional fundraising efforts may divert our management from their day-to-day activities, which may adversely affect our ability to develop and commercialize our product candidates. In addition, we cannot guarantee that future financing will be available in sufficient amounts or on terms acceptable to us, if at all. Subject to limited exceptions, our loan and security agreement also prohibits us from incurring indebtedness without the prior written consent of the lenders. Moreover, the terms of any financing may adversely affect the holdings or the rights of our stockholders and the issuance of additional securities, whether equity or debt, by us, or the possibility of such issuance, may cause the market price of our shares to decline. The sale of additional equity or convertible securities would dilute all of our stockholders. The incurrence of indebtedness would result in increased fixed payment obligations and we may be required to agree to certain restrictive covenants, such as limitations on our ability to incur additional debt, limitations on our ability to acquire, sell or license intellectual property rights and other operating restrictions that could adversely impact our ability to conduct our business. We could also be required to seek funds through arrangements with collaborative partners or otherwise at an earlier stage than otherwise would be desirable and we may be required to relinquish rights to some of our technologies or product candidates or otherwise agree to terms unfavorable to us, any of which may have a material adverse effect on our business, operating results and prospects.

If we are unable to obtain funding on a timely basis, we may be required to significantly curtail, delay or discontinue one or more of our research or development programs or the commercialization of any product candidates or be unable to expand our operations or otherwise capitalize on our business opportunities, as desired, which could materially affect our business, financial condition and results of operations.

Immunotherapy, gene therapy and biopharmaceutical product development is a highly speculative undertaking and involves a substantial degree of uncertainty. We have never generated any revenue from product sales and may never be profitable.

Since our inception in August 2007, we have devoted substantially all of our efforts to developing our gene therapy platform and our lead product candidate, Toca 511 & Toca FC. We are still developing our product candidates, and we have not completed development of any products. Our ability to generate revenue and achieve profitability depends in large part on our ability, alone or with partners, to successfully complete the development of, obtain the necessary regulatory approvals for, and commercialize product candidates. We do not anticipate generating revenues from sales of products for the foreseeable future. Our ability to generate future revenues from product sales depends heavily on our success in:

Because of the numerous risks and uncertainties associated with gene therapy product development, we are unable to predict the timing or amount of increased expenses or when we will be able to achieve or maintain profitability, if ever. In addition, our expenses could increase beyond expectations if we are required by the U.S. Food and Drug Administration, or FDA, or foreign regulatory agencies, to perform studies and clinical trials in addition to those that we currently anticipate or if there are any delays in the development of any of our product candidates. If one or more of the product candidates that we develop is approved for commercial sale, we anticipate incurring significant costs associated with commercializing such product candidates. Even if we are able to generate revenues from the sale of any approved products, we may not become profitable and may need to obtain additional funding to continue operations, which may not be available to us on favorable terms, if at all. Even if we do achieve profitability, we may not be able to sustain or increase profitability on a quarterly or annual basis. Our failure to become and remain profitable would depress the value of our company and could impair our ability to raise capital, expand our business, maintain our research and development efforts, diversify our product offerings or even continue our operations. A decline in the value of our company could also cause you to lose all or part of your investment.

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Our gene therapy product candidates are based on novel technology, which makes it difficult to predict the time and cost of product candidate development.

We have concentrated our product research and development efforts on our gene therapy platform, and our future success depends on the successful development of this therapeutic approach. There can be no assurance that any development problems we experience in the future related to our gene therapy platform will not cause significant delays or unanticipated costs, or that such development problems can be solved. We may also experience delays in developing a sustainable, reproducible and scalable manufacturing process or transferring that process to commercial partners, or developing or validating product release assays in a timely manner, which may prevent us from completing our clinical trials or commercializing our products on a timely or profitable basis, if at all.

In addition, the clinical trial requirements of the FDA, the European Medicines Agency, or EMA, and other regulatory agencies and the criteria these regulators use to determine the safety and efficacy of a product candidate vary substantially according to the type, complexity, novelty and intended use and market of the potential products. The regulatory approval process for novel product candidates such as ours can be more expensive and take longer than for other, better known or extensively studied pharmaceutical or other product candidates. In October 2015, the FDA approved Amgen Inc.’s oncolytic virus therapy, Imlygic (talimogene laherparapvec), for the local treatment of unresectable lesions in patients with melanoma recurrent after initial surgery and in December 2015, Imlygic was approved by the European Commission for early stage, unresectable melanoma that is regionally or distantly metastatic following a recommendation for marketing authorization as a gene therapy in Europe by the Committee for Advanced Therapies. In 2017, the FDA approved the first two CAR T cell therapy products: Novartis’ Kymriah (tisagenlecleucel), for the treatment of a type of leukemia and Kite Pharma’s Yescarta (axicabtagene ciloleucel), for the treatment of a type of lymphoma.  On December 19, 2017, the FDA approved Spark Therapeutics, Inc.’s Luxturna (voretigene neparvovec-rzyl), a new gene therapy, to treat children and adult patients with an inherited form of vision loss that may result in blindness. Two other gene therapy products have been approved in Europe, uniQure NV’s Glybera (alipogene tiparvovec), which received marketing authorization from the European Commission in 2012 and GlaxoSmithKline, Fondazione Telethon and Ospedale San Raffaele’s Strimvelis (GSK2696273), which was approved by the European Commission in 2016. The limited precedent for gene therapy approvals makes it difficult to determine how long it will take or how much it will cost to obtain regulatory approvals for our product candidates in either the United States or Europe.  

Regulatory requirements governing gene therapy products have changed frequently and may continue to change in the future. For example, in January 2017, the FDA Oncology Center of Excellence, or the Center of Excellence, was created to leverage the combined skills of regulatory scientists and reviewers with expertise in drugs, biologics, and devices (including diagnostics). While the Center of Excellence is designed to help expedite the development of oncology and malignant hematology-related medical products and support an integrated approach in the clinical evaluation of drugs, biologics and devices for the treatment of cancer, the new Center of Excellence may initially create confusion within the FDA and especially in the Center of Biologics and Research that is the primary review division for our initial product candidate. Gene therapy clinical trials conducted at institutions that receive funding for recombinant DNA research from the U.S. National Institutes of Health, or the NIH, are also subject to review by the NIH Office of Biotechnology Activities’ Recombinant DNA Advisory Committee, or the RAC. We have received from time to time questions from the FDA regarding investigational new drug application, or IND, submissions and clinical protocols for Toca 511 & Toca FC. We believe that we have adequately addressed these questions, some of which have caused, in the past, some delays in our clinical trials. Although the FDA decides whether individual gene therapy protocols may proceed, the RAC review process can impede the initiation of a clinical trial, even if the FDA has reviewed the study and approved its initiation. Conversely, the FDA can put an IND on a partial or complete clinical hold even if the RAC has provided a favorable review. Our trials have, in the past, been put on hold for reasons including suspected serious adverse events, which resulted in delays of our trials. Also, before a clinical trial can begin at an NIH-funded institution, that institution’s institutional review board, or IRB, and its Institutional Biosafety Committee will have to review the proposed clinical trial to assess the safety of the study. In addition, adverse developments in clinical trials of gene therapy products conducted by others may cause the FDA or other regulatory bodies to change the requirements for performing studies or for obtaining approval of any of our product candidates.

These regulatory review committees and advisory groups, and the new guidelines they promulgate, may lengthen the regulatory review process, require us to perform additional studies, increase our development costs, lead to changes in regulatory positions and interpretations, delay or prevent approval and commercialization of our product candidates or lead to significant post-approval limitations or restrictions. As we advance our product candidates, we will be required to consult with these regulatory and advisory groups and comply with applicable guidelines. Delay or failure to obtain, or unexpected costs in obtaining, the regulatory approval necessary to bring a potential product to market could decrease our ability to generate sufficient revenue to maintain our business.

Failure to successfully develop and obtain approval of our lead product candidate, Toca 511 & Toca FC, or our other future product candidates could adversely affect our future success.

Our business and future success is substantially dependent on our ability to obtain regulatory approval of and then successfully commercialize our lead product candidate, Toca 511 & Toca FC which is in clinical development. All of our product candidates, including Toca 511 & Toca FC, will require additional clinical and nonclinical development, regulatory review and approval in one or

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more jurisdictions, substantial investment, access to sufficient pre-commercial and commercial manufacturing capacity and significant marketing efforts before we can generate any revenue from product sales. In addition, because Toca 511 & Toca FC is our most advanced product candidate, and because all of our other future product candidates will likely be based on similar technology, if Toca 511 & Toca FC encounters safety or efficacy problems, developmental delays, regulatory issues or other problems, our development plans and business for our other product candidates would be significantly harmed.

We may have difficulty enrolling patients in our clinical trials, which could delay or prevent development of our product candidates.

Identifying and qualifying patients to participate in clinical trials of our product candidates is critical to our success. The timing of our clinical trials depends on the speed at which we can recruit patients to participate in testing our product candidates. We have experienced delays in some of our clinical trials in the past due to difficulties with enrollment and we may experience similar delays in the future. If patients are unwilling to participate in our clinical trials because of negative publicity from adverse events in the industry or in the trials for other third party product candidates, or for other reasons, including competitive clinical trials for similar patient populations, the timeline for recruiting patients, conducting studies and obtaining regulatory approval of potential products may be delayed. These delays could result in increased costs, delays in advancing our product development, delays in testing the effectiveness of our technology or termination of the clinical trials altogether.

We or our clinical trial sites may not be able to identify, recruit and enroll a sufficient number of patients, or those with the required or desired characteristics in a clinical trial, to complete our clinical trials in a timely manner. Patient enrollment is affected by factors including:

In particular, recurrent high grade glioma, or HGG, the condition for which we are initially evaluating our lead product candidate, has a limited number of patients for clinical trials. The eligibility criteria of our clinical trials will further limit the pool of available trial participants. For example, some clinical trials will be limited to patients with recurrent HGG who are scheduled for a repeat resection, for which there are fewer patients. Additionally, the process of finding and diagnosing patients may prove costly. Finally, our treatment necessitates that the patient be near one of our clinical trial sites, since periodic follow-up visits at the clinical trial site are contemplated in the protocols.

We currently plan to seek initial marketing approval in the United States and subsequently other pharmaceutical markets. We may not be able to initiate or continue clinical trials if we cannot enroll a sufficient number of eligible patients to participate in the clinical trials required by the FDA, the EMA or other regulatory agencies. Our ability to successfully initiate, enroll and complete a clinical trial in any foreign country is subject to numerous risks unique to conducting business in foreign countries, including:

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If we have difficulty enrolling a sufficient number of patients to conduct our clinical trials as planned, we may need to delay, limit or terminate ongoing or planned clinical trials, any of which would have an adverse effect on our business.

The FDA regulatory approval process is lengthy and time-consuming, and we may experience significant delays in the clinical development and regulatory approval of our product candidates. If we are ultimately unable to obtain regulatory approval for our product candidates, our business will be substantially harmed.

The time required to obtain approval by the FDA and comparable foreign authorities is unpredictable but typically takes many years following the commencement of clinical trials and depends upon numerous factors, including the substantial discretion of the regulatory authorities. In addition, approval policies, regulations or the type and amount of clinical data necessary to gain approval may change during the course of a product candidate’s clinical development and may vary among jurisdictions. We have not obtained regulatory approval for any product candidate and it is possible that none of our existing product candidates or any product candidates we may seek to develop in the future will ever obtain regulatory approval.

We have not previously submitted a biologics license application, or BLA, to the FDA, or similar approval filings to comparable foreign authorities. A BLA must include extensive preclinical and clinical data and supporting information to establish the product candidate’s safety, purity and potency for each desired indication. The BLA must also include significant information regarding the chemistry, manufacturing and controls for the product. Clinical testing is expensive, time-consuming and uncertain as to outcome. We have experienced in the past delays in the commencement and completion of our clinical trials. We cannot guarantee that any clinical trials will be conducted as planned or completed on schedule, if at all. A failure of one or more clinical trials can occur at any stage of testing. In addition to challenges related to patient enrollment, other events that may prevent successful or timely completion of clinical development include:

We could also encounter delays if physicians encounter unresolved ethical issues associated with enrolling patients in clinical trials of our product candidates in lieu of prescribing existing treatments that have established safety and efficacy profiles. Further, a clinical trial may be suspended or terminated by us, the IRBs for the institutions in which such clinical trials are being conducted, the Data Safety Monitoring Committee for such clinical trial, by the FDA or other regulatory authorities due to a number of factors, including failure to conduct the clinical trial in accordance with regulatory requirements or our clinical protocols, inspection of the clinical trial operations or clinical trial site by the FDA or other regulatory authorities resulting in the imposition of a clinical hold, unforeseen safety issues or adverse side effects, failure to demonstrate a benefit from using a product candidate, changes in governmental regulations or administrative actions or lack of adequate funding to continue the clinical trial. If we experience termination of, or delays in the completion of, any clinical trial of our product candidates, the commercial prospects for our product candidates will be harmed, and our ability to generate product revenue will be delayed. In addition, any delays in completing our

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clinical trials will increase our costs, slow down our product development and approval process and jeopardize our ability to commence product sales and generate revenue.

Any inability to successfully complete preclinical and clinical development could result in additional costs to us or impair our ability to generate revenues from product sales, regulatory and commercialization milestones and royalties. In addition, if we make manufacturing or formulation changes to our product candidates, we may need to conduct additional studies to bridge our modified product candidates to earlier versions. Clinical trial delays could also shorten any periods during which we may have patent protection rights to commercialize our product candidates or allow our competitors to bring products into clinical trials or to market before we do, which could impair our ability to successfully commercialize our product candidates and may harm our business and results of operations.

Our clinical trials may fail to demonstrate safety and efficacy and any of our product candidates could be associated with undesirable side effects or other properties, which would prevent or delay regulatory approval and commercialization.

Before obtaining marketing approval from regulatory authorities for the sale of our product candidates, we must conduct extensive clinical trials to demonstrate the safety and efficacy of the product candidates in humans. Failure can occur at any time during a clinical trial process. The results of preclinical studies and early clinical trials of our product candidates may not be predictive of the results of later-stage clinical trials. There is typically an extremely high rate of attrition from the failure of product candidates proceeding through clinical trials. Product candidates in later stages of clinical trials may fail to show the desired safety and efficacy profile despite having progressed through preclinical testing and initial clinical trials. Most product candidates that commence clinical trials are never approved as products.

In addition, from time to time, we may publish interim, “top-line,” initial, or preliminary data from our clinical studies. Interim data from clinical trials are subject to the risk that one or more of the clinical outcomes may materially change as patient enrollment continues and more patient data becomes available. Preliminary, initial, or “top-line” data also remain subject to audit and verification procedures that may result in the final data being materially different from the preliminary data we previously published. As a result, interim, initial, and preliminary data should be viewed with caution until the final data are available. Adverse changes between preliminary, initial, “top-line” or interim data and final data could significantly harm our business prospects. In the 127 patients who received Toca 511 in our Phase 1 clinical trials, treatment-related adverse events were reported in 32.3% of patients and these events were predominantly low grade (25.2%). The most common treatment-related adverse events were fatigue (11.8%), headache (5.5%), and convulsion (4.7%). In the 122 patients who received Toca FC in our ascending Phase 1 clinical trials, treatment-related adverse events were reported in 44.3% of patients and these events were predominantly low grade (41.0%). The most common treatment-related adverse events were fatigue (22.1%), diarrhea (13.9%), and nausea (9.8%). Treatment-related serious adverse events were reported in 6.3% of patients treated with Toca 511 and 1.6% of patients treated with Toca FC. In patients that received both Toca 511 and Toca FC, hematologic toxicity was infrequent and also low grade. Patients treated with our product candidates may also be undergoing surgical, radiation and chemotherapy treatments, which can cause side effects or adverse events that are unrelated to our product candidate, but may still impact the success of our clinical trials. Additionally, our product candidates could potentially cause other adverse events that have not yet been predicted. The inclusion of critically ill patients in our clinical trials may result in deaths or other adverse medical events due to other therapies or medications that such patients may be using or due to the gravity of such patients’ illnesses. Patients who will be administered Toca 511 & Toca FC in the HGG clinical trials are seriously or terminally ill and some of them may have immune impairment related to their treatment with temozolomide and dexamethasone. It is expected that some of the patients will die or experience major clinical events such as strokes, hydrocephalus, infections, brain swelling and pulmonary emboli either during the course of our clinical trials or after such trials, which has occurred in the past.  In some patients with evidence of drug activity from Toca 511 & Toca FC, new lesions have been observed, some of which continue to grow even with continued Toca FC treatment.

Further, the design of our ongoing Phase 3 clinical trial of Toca 511 & Toca FC was based in part on survival data from similar patients in published trials. The prognosis, unrelated to our treatment, for our patients could be better than for patients in these prior trials, due to improvements in clinical practice, other experimental trials or underappreciated differences in entry criteria. In addition, the clinical or regulatory opinion on what constitutes the standard of care that we have used as the basis for the control arm in this clinical trial may change before we submit the BLA for Toca 511 & Toca FC, if the clinical trial is successful.

It is possible that our retroviral replicating vector, or RRV, product candidates will spread to healthy tissues and result in unknown side effects, and that any anticipated or unanticipated side effects may occur at doses required to achieve clinically relevant efficacy, which could prohibit or delay commercialization of our product candidates. Alternatively, our RRV product candidates might not spread rapidly enough through the tumor or transfer sufficient genetic material to the tumor to demonstrate efficacy sufficient for regulatory approval. In preclinical studies in rodent models, we observed that our vectors do not initially infect tumors in some locations as well as they infect tumors in other locations, which may limit treatment with our future product candidates to a limited number of cancer locations. Further, it is possible that the RRV might not spread fast enough through the brain cancer to have a beneficial effect or that the virus might not be able to reach certain parts of the tumor due to prior surgical removal of contiguous cancer tissue or from scarring resulting from surgery, chemotherapy, radiation or spontaneous tumor necrosis (cell death) or due to

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mechanical limitations such as the inability to insert the needle accurately into the tumor; the inability to push enough RRV volume into a tumor with a high pressure; the rapid diffusion of RRV from the injection site due to high intratumor pressure or due to the communication with the ventricular space, external cerebral spinal fluid or the entry into veins; or the inability to insert the needle into the tumor without damaging vital brain structures. It is possible that the cancers which we seek to treat with our product candidates will become resistant to infection with the virus or become resistant to the 5-FU (5-fluorouracil) produced from Toca FC, due to mutation within the cancer cells genes or due to mutation of Toca 511, including loss of the therapeutic gene, cytosine deaminase.

If the results of our clinical trials are inconclusive or if there are safety concerns or adverse events associated with our product candidates, we may:

In third-party clinical trials involving other viral vectors for gene therapy, some patients experienced serious adverse events, including the development of leukemia due to vector-related insertional oncogenesis and death. If our vectors demonstrate a similar effect, we may be required to halt or delay clinical development of our product candidates.

Existing data on the safety and efficacy of gene therapy is very limited and sometimes include historically poor clinical efficacy of previous non-replicating gene therapy products. In addition, there have been publicized safety issues associated with previous gene therapy products in third-party clinical trials, including patient deaths. The results of preclinical and clinical trials performed for our product candidates do not definitively predict safety or efficacy in humans. Possible serious side effects of other viral vector-based gene therapy therapies in general include uncontrolled viral infections and the development of cancer, particularly lymphoma or leukemia.

A significant risk in any gene therapy product based on viral vectors that integrate into the host genome at measurable frequencies is that the vector will insert near cancer-causing oncogenes leading to uncontrolled clonal proliferation of mature cancer cells in the patient. For example, in 2003, 20 patients treated for X-linked severe combined immunodeficiency in two gene therapy studies conducted by third parties using a murine gamma-retroviral vector showed correction of the disease, but the studies were terminated after five patients developed leukemia. The cause of these adverse events was believed to be related to insertional oncogenesis, which is the process whereby the corrected gene inserts near a gene that is important in a critical cellular process like growth or division, and this insertion results in the development of a cancer (often leukemia). A potential clinical concern for gene therapy using retroviral vectors has been the possibility of insertional mutagenesis by the vectors, leading to malignant transformation of transduced cells (i.e., cancer). Because our replicating retroviruses produce viral antigens, these foreign proteins could serve as a target for immune activation against virally-infected cells and inflammation, which is not a feature of non-replicating retroviral vectors. In addition, we have not, and do not plan to, treat patients with severe immunodeficiency with our product candidates. Further, with our lead product candidate, Toca FC kills the virally-infected cells and presents the antigens. We believe that we have not observed oncogenesis in the patients treated in our clinical trials to date for these reasons. Our future product candidates are also designed to activate the immune system against virally-infected cells.

It is possible Toca 511 may spread to non-tumor tissue. We have detected transient and low levels of viral sequences in the saliva of several patients. The risk of insertional mutagenesis or oncogenesis remains a significant concern for gene therapy, and we cannot provide any assurance that it will not occur in any of our current, planned or future clinical trials. There is also the potential risk of delayed adverse events following exposure to gene therapy products due to persistent biological activity of the genetic material or other components of products used to carry the genetic material. If any such adverse events occur, further advancement of our clinical trials could be halted or delayed, which would have a material adverse effect on our business and operations.

We may not be successful in our efforts to identify or discover additional product candidates from our gene therapy platform.

The success of our business depends primarily upon our ability to identify, develop and commercialize products based on our gene therapy platform. Although our Toca 511 & Toca FC product candidate is currently in clinical development, our research

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programs may fail to identify other potential product candidates for clinical development. Our research methodology may be unsuccessful in identifying potential product candidates, or our potential product candidates may be shown to have harmful side effects or may have other characteristics that may make the products unmarketable or unlikely to receive marketing approval. If any of these events occur, we may be forced to abandon our development efforts for a program or programs, which would have a material adverse effect on our business and could potentially cause us to cease operations.

We rely, and expect to continue to rely, on third parties to conduct, supervise and monitor our clinical trials, and if these third parties perform in an unsatisfactory manner, it may harm our business.

We rely on CROs and clinical trial sites to ensure our clinical trials are conducted properly and on time. While we have agreements governing their activities, we may have limited influence over their actual performance. We control only certain aspects of our CROs’ activities. Nevertheless, we are responsible for ensuring that each of our clinical trials is conducted in accordance with the applicable protocol, legal, regulatory and scientific standards, and our reliance on the CROs does not relieve us of our regulatory responsibilities.

We and our CROs are required to comply with the GCPs for conducting, recording, auditing and reporting the results of clinical trials to assure that the data and reported results are credible and accurate and that the rights, integrity and confidentiality of clinical trial participants are protected. The FDA enforces these GCPs through periodic inspections of study sponsors, principal investigators and clinical trial sites. If we or our CROs fail to comply with applicable GCPs, the clinical data generated in our future clinical trials may be deemed unreliable, and the FDA may require us to perform additional clinical trials before approving any marketing applications. Upon inspection, the FDA may determine that our clinical trials did not comply with GCPs. In addition, our ongoing and future clinical trials will require a sufficient number of test subjects to evaluate the safety and effectiveness of our product candidates. Accordingly, if our CROs fail to comply with these regulations or fail to recruit a sufficient number of patients, we may be required to repeat such clinical trials, which would delay the regulatory approval process.

Our CROs are not our employees, and we are not able to directly monitor whether or not they devote sufficient time and resources to our clinical and nonclinical programs. These CROs may also have relationships with other commercial entities, including our competitors, for whom they may also be conducting clinical trials or other drug development activities that could harm our competitive position. If our CROs do not successfully carry out their contractual duties or obligations, fail to meet expected deadlines, or if the quality or accuracy of the clinical data they obtain is compromised due to their failure to adhere to our clinical protocols or regulatory requirements, or for any other reasons, our clinical trials may be extended, delayed or terminated, and we may not be able to obtain regulatory approval for or successfully commercialize our product candidates. As a result, our financial results and the commercial prospects for our product candidates would be harmed, our costs could increase and our ability to generate revenues could be delayed.

We expect to continue to rely on third parties to distribute, manufacture and perform release testing for our vectors, product candidates and other key materials and if such third parties do not carry out their contractual duties or meet expected deadlines, we may not be able to obtain regulatory approvals for our product candidates.

We intend to continue to rely on third-party contract manufacturing organizations, or CMOs, to produce our vectors, product candidates and other key materials and on third-party contract testing organizations, or CTOs, for the establishment and performance of validated product release assays, but we have not entered into binding agreements with any such CMOs or CTOs to support commercialization. Additionally, any CMO may not have experience or availability to produce adequate product candidates at commercial levels and may not achieve the necessary regulatory approvals or produce our vectors and products at the quality, quantities, locations and timing needed to support commercialization. We may change our manufacturing process from the current defined media process to a different defined media process, or from its current equipment to different equipment, or our cell line or vector and there can be no guarantee that the regulatory authorities will approve this new process in a timely manner or ever. Also, as a consequence of the manufacturing change, there may be a requirement to do more preclinical safety or efficacy studies, develop new manufacturing and release assays and/or repeat all or part of the ascending dose safety study in animals or humans. Regulatory requirements ultimately imposed could adversely affect our ability to test, manufacture or market products.

We have not yet secured manufacturing capabilities for commercial quantities of our viral vector. Although we intend to rely on third-party manufacturers for commercialization, we currently utilize a sole-source manufacturer to support our clinical trials. We may be unable to negotiate binding agreements with this manufacturer or additional manufacturers to support our commercialization activities at commercially reasonable terms.

No manufacturer we know of currently has the direct experience or the demonstrated ability to produce our vectors and product candidates at reasonable commercial levels or under full commercial requirements. We have developed in-house, a more scalable manufacturing process for Toca 511, which we are transferring to one or more CMOs. We may run into technical or scientific issues related to manufacturing or development that we may be unable to resolve in a timely manner or with available funds. Further, we

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have not completed the characterization and validation activities necessary for commercial and regulatory approvals. If our manufacturing and testing partners do not satisfy such regulatory requirements, our commercialization efforts may be harmed.

Similarly, we currently have a single manufacturer of the active pharmaceutical ingredient for Toca-FC and another single manufacturer of the final drug product. We also rely on outside contractors to perform validated release testing for Toca FC. Currently we have not fully validated production of the drug product, Toca FC.

Even if we have developed manufacturing processes for Toca 511 and Toca FC and successfully implement them at third-party manufacturers, if such third-party manufacturers are unable to produce viral vectors and our product candidates in the necessary quantities, or in compliance with current good manufacturing practices, or cGMP, or in compliance with pertinent regulatory requirements, and within our planned time frame and cost parameters, the development and sales of our products, if approved, may be materially harmed. The facilities used by our contract manufacturers to manufacture our product candidates must be approved by the FDA pursuant to inspections that will be conducted after we submit our BLA to the FDA. We do not directly control the manufacturing process of, and are completely dependent on, our contract manufacturing partners for compliance with cGMPs for the manufacture of our product candidates. If our contract manufacturers cannot successfully manufacture material that conforms to our specifications and the strict regulatory requirements of the FDA or others, they will not be able to secure and/or maintain regulatory approval for their manufacturing facilities. In addition, we have no control over the ability of our contract manufacturers to maintain adequate quality control, quality assurance and qualified personnel. If the FDA or a comparable foreign regulatory authority does not approve these facilities for the manufacture of our product candidates or if it withdraws any such approval in the future, we may need to find alternative manufacturing facilities, which would significantly impact our ability to develop, obtain regulatory approval for or market our product candidates, if approved. In addition, any failure to achieve and maintain compliance with these laws, regulations and standards could subject us to the risk that we may have to suspend the manufacturing of our product candidates or that obtained approvals could be revoked, which would adversely affect our business and reputation.

In addition, any significant disruption in our supplier relationships could harm our business. We source key materials, devices and equipment from third parties, either directly through agreements with suppliers or indirectly through our manufacturers who have agreements with suppliers. There are a small number of suppliers for certain key materials, equipment, software and components that are used to manufacture our product candidates. Such suppliers may not sell these key materials to our manufacturers at the times or quantities we need them or on commercially reasonable terms. We may not have any control over the process, quality or timing of the acquisition of these key materials by our manufacturers.

We also expect to rely on other third parties to store and distribute our vectors and products for our clinical trials. Any performance failure on the part of our distributors could delay clinical development or marketing approval of our product candidates or commercialization of our products, if approved, producing additional losses and depriving us of potential product revenue.

Our reliance on third parties may require us to share our trade secrets, which increases the possibility that a competitor will discover them or that our trade secrets will be misappropriated or disclosed.

Because we rely on third parties to manufacture our vectors and our product candidates, and because we collaborate with various organizations and academic institutions on the advancement of our gene therapy platform, we must, at times, share trade secrets with them. We seek to protect our proprietary technology in part by entering into confidentiality agreements and, if applicable, material transfer agreements, collaborative research agreements, consulting agreements or other similar agreements with our manufacturers, collaborators, advisors, employees and consultants prior to beginning research or disclosing proprietary information. These agreements typically limit the rights of the third parties to use or disclose our confidential information, such as trade secrets. Despite the contractual provisions employed when working with third parties, the need to share trade secrets and other confidential information increases the risk that such trade secrets become known by our competitors, are inadvertently incorporated into the technology of others, are used inappropriately to create new inventions or are disclosed or used in violation of these agreements. Given that our proprietary position is based, in part, on our know-how and trade secrets, a competitor’s discovery of our trade secrets or other unauthorized use or disclosure would impair our competitive position and may have a material adverse effect on our business.

In addition, these agreements typically restrict the ability of our collaborators, advisors, employees and consultants to publish data potentially relating to our trade secrets. Our academic collaborators typically have rights to publish data, provided that we are notified in advance and may delay publication for a specified time in order to secure our intellectual property rights arising from the collaboration. In other cases, publication rights are controlled exclusively by us, although in some cases we may share these rights with other parties. We also conduct joint research and development programs that may require us to share trade secrets under the terms of our research and development partnerships or similar agreements. Despite our efforts to protect our trade secrets, our competitors may discover our trade secrets through breach of these agreements, independent development or publication of information including our trade secrets in cases where we do not have proprietary or otherwise protected rights at the time of publication. A competitor’s discovery of our trade secrets may impair our competitive position and have an adverse impact on our business.

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We face intense competition and rapid technological change and the possibility that our competitors may develop therapies that are more advanced or effective than ours, which may adversely affect our financial condition and our ability to successfully commercialize our product candidates.

We are engaged in developing gene therapies and cancer immunotherapies, which are rapidly evolving and fiercely competitive fields. A wide variety of institutions in the United States and internationally, including major multinational pharmaceutical companies, specialty biotechnology companies, academic research departments and public and private institutions, are actively developing potentially competitive technology and products. We face substantial competition from biotechnology and pharmaceutical companies developing products in immunotherapy and our initial proposed indication. Our competitors generally fall into the following categories: companies developing checkpoint inhibitors; companies developing immunotherapies; companies aimed at stimulating immune responses; companies developing CAR and TCR T cells; companies developing oncolytic virus-based technology; and companies with a focus on HGG.

Many of our competitors have substantially greater financial, technical and other resources, such as larger research and development staff and experienced marketing and manufacturing organizations. Accordingly, our competitors may be more successful than us in obtaining approval for treatments and achieving widespread market acceptance, rendering our treatments obsolete or non-competitive. These companies also compete with us in recruiting and retaining qualified scientific and management personnel, establishing clinical trial sites and patient registration for clinical trials and acquiring technologies complementary to, or necessary for, our programs. Smaller or early-stage companies may also prove to be significant competitors, particularly through collaborative arrangements with large and established companies.

If these competitors develop and commercialize more effective, safer or less toxic products than us or if they obtain regulatory approval before us in key geographies, our commercial opportunities could be substantially limited. In addition, adverse clinical outcomes or similar events at gene therapy companies in the past have adversely affected other companies in this field and could also do so in the future at our company.

Even if we obtain regulatory approval of our product candidates, the products may not gain market acceptance among physicians, patients, hospitals, cancer treatment centers, third-party payors and others in the medical community.

Ethical, social and legal concerns about gene therapy and genetic research could result in additional regulations restricting or prohibiting the products and processes we may use. Even with the requisite approvals, the commercial success of our product candidates will depend in part on the medical community, patients, and third-party payors accepting gene therapy products in general, and our product candidates in particular, as medically useful, cost-effective and safe. Any product that we bring to the market may not gain market acceptance by physicians, patients, third-party payors and others in the medical community. If these products do not achieve an adequate level of acceptance, we may not generate significant product revenue and may not become profitable. The degree of market acceptance of these product candidates, if approved for commercial sale, will depend on a number of factors, including:

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Even if a potential product displays a favorable efficacy and safety profile in preclinical and clinical trials, market acceptance of the product will not be known until after it is launched. Our efforts to educate the medical community and third-party payors on the benefits of the product candidates may require significant resources and may never be successful. Such efforts to educate the marketplace may require more resources than are required by the conventional technologies marketed by our competitors and may be restricted by the allowed label.

We are highly dependent on our key personnel, and if we are not successful in attracting and retaining highly qualified personnel, we may not be able to successfully implement our business strategy.

Our ability to compete in the highly competitive biotechnology and pharmaceutical industries depends upon our ability to attract and retain highly qualified managerial, scientific and medical personnel. We are highly dependent on our management, scientific and medical personnel, including our Chief Executive Officer and our Chief Financial Officer. The loss of the services of any of our executive officers, other key employees and other scientific and medical advisors, and our inability to find suitable replacements, could result in delays in product development and harm our business.

To induce valuable employees to remain at our company, in addition to salary and cash incentives, we have provided stock options that vest over time. The value to employees of stock options that vest over time may be significantly affected by movements in our stock price that are beyond our control and may at any time be insufficient to counteract more lucrative offers from other companies. Despite our efforts to retain them, valuable employees and members of our management, scientific and development teams may terminate their employment with us at any time, with or without notice. We do not maintain “key man” insurance policies on the lives of any of our executive officers or other employees. Our success also depends on our ability to continue to attract, retain and motivate highly skilled scientific and medical personnel.

We will need to expand our organization and we may experience difficulties in managing this growth, which could disrupt our operations.

As of December 31, 2017, we had 67 full-time employees. As our development and commercialization plans and strategies develop, and as we continue operating as a public company, we expect to need additional managerial, operational, sales, marketing, financial and other personnel. Future growth would impose significant added responsibilities on members of management. There are a small number of individuals with experience in gene therapy and clinicians who have successfully developed drugs and the competition for such individuals is high. Our future financial performance and our ability to commercialize our product candidates will depend, in part, on our ability to effectively manage any future growth, and our management may also have to divert a disproportionate amount of its attention away from day-to-day activities in order to devote a substantial amount of time to managing these growth activities. Our business operations may be disrupted and management’s attention may be diverted as we move to our new laboratory and office space in 2018, which could harm our business and prospects. We currently rely, and for the foreseeable future will continue to rely on certain independent organizations, advisors and consultants to provide certain services, including substantially all aspects of regulatory approval, clinical management and manufacturing. There can be no assurance that the services of independent organizations, advisors and consultants will continue to be available to us on a timely basis when needed or that we can find qualified replacements. In addition, if we are unable to effectively manage our outsourced activities or if the quality or accuracy of the services provided by consultants is compromised for any reason, our clinical trials may be extended, delayed or terminated, and we may not be able to obtain regulatory approval of our product candidates or otherwise advance our business. There can be no assurance that we will be able to manage our existing consultants or find other competent outside contractors and consultants on economically reasonable terms, or at all.

If we are not able to effectively expand our organization by hiring new employees and expanding our groups of consultants and contractors, we may not be able to successfully implement the tasks necessary to further develop and commercialize our product candidates and, accordingly, may not achieve our research, development and commercialization goals.

We may use our financial and human resources to pursue a particular research program or product candidate and fail to capitalize on programs or product candidates that may be more profitable or for which there is a greater likelihood of success.

Because we have limited resources, we may forego or delay pursuit of opportunities with certain programs or product candidates or for indications that later prove to have greater commercial potential. Our resource allocation decisions may cause us to fail to capitalize on viable commercial products or profitable market opportunities. Our spending on current and future research and development programs for product candidates may not yield any commercially viable products. If we do not accurately evaluate the commercial potential or target market for a particular product candidate, we may relinquish valuable rights to that product candidate through strategic collaboration, licensing or other royalty arrangements in cases in which it would have been more advantageous for us to retain sole development and commercialization rights to such product candidate, or we may allocate internal resources to a product candidate in a therapeutic area in which it would have been more advantageous to enter into a partnering arrangement.

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We currently have a very limited marketing and sales organization. If we are unable to expand our marketing and sales capabilities or enter into agreements with third parties to market and sell our product candidates, we may not be able to generate product revenue.

We currently have very limited sales, marketing and distribution capabilities. At the appropriate time, we plan to build a commercial infrastructure targeting oncologists, neuro-oncologists and neurosurgeons and related clinicians and health care workers in leading and regional cancer centers in the United States, which will require significant capital expenditures, management resources and time. Outside the United States, we may build our own commercial infrastructure or consider opportunities to enter into out-licensing or co-promotion agreements with other pharmaceutical or biotechnology companies to develop and/or commercialize our product candidates outside the United States. We will have to compete with other pharmaceutical and biotechnology companies to recruit, hire, train and retain marketing and sales personnel.

If we are unable or decide not to establish internal sales, marketing and distribution capabilities, we will pursue collaborative arrangements regarding the sales and marketing of our products, however, there can be no assurance that we will be able to establish or maintain such collaborative arrangements, or if we are able to do so, that they will have effective sales forces. Any revenue we receive will depend upon the efforts of such third parties, which may not be successful. We may have little or no control over the marketing and sales efforts of such third parties, and our revenue from product sales may be lower than if we had commercialized our product candidates ourselves. We also face competition in our search for third parties to assist us with the sales and marketing efforts of our product candidates.

There can be no assurance that we will be able to develop in-house sales and distribution capabilities or establish or maintain relationships with third-party collaborators to commercialize any product in the United States or elsewhere.

A variety of risks associated with marketing our product candidates internationally could materially adversely affect our business.

We plan to seek regulatory approval of our product candidates outside of the United States and, accordingly, we expect that we will be subject to additional risks related to operating in foreign countries if we obtain the necessary approvals, including:

These and other risks associated with our international operations may materially adversely affect our ability to attain or maintain profitable operations.

The terms of our loan and security agreement place restrictions on our operating and financial flexibility.

In October 2015, we entered into a loan and security agreement with Oxford Finance LLC and Silicon Valley Bank that is secured by substantially all of our assets other than our intellectual property (except rights to payment from the sale, licensing or disposition of such intellectual property). We borrowed $18.0 million upon execution of the loan and security agreement.

The loan and security agreement includes affirmative and negative covenants applicable to us and any subsidiaries we create in the future. The affirmative covenants include, among others, covenants requiring us to maintain our legal existence and governmental approvals, deliver certain financial reports, maintain insurance coverage, and subject all of our deposit accounts, securities accounts, commodity accounts or any other bank accounts, to a control agreement in favor of Oxford Finance LLC. The negative covenants

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include, among others, restrictions on us transferring collateral, incurring additional indebtedness, engaging in mergers or acquisitions, paying dividends in cash or making other distributions, making investments, creating liens, selling assets, and suffering a change in control, in each case subject to certain exceptions.

The loan and security agreement also includes events of default, the occurrence and continuation of which provide Oxford Finance LLC, as collateral agent, with the right to exercise remedies against us and the collateral securing the loans under the loan and security agreement, including foreclosure against our properties securing the loan and security agreement, including our cash, potentially requiring us to renegotiate our agreement on terms less favorable to us or to immediately cease operations. These events of default include, among other things, our failure to pay any amounts due under the loan and security agreement, a breach of covenants under the loan and security agreement, our insolvency, impairment in the perfection or priority of each lender’s security interest in the collateral, the occurrence of any default under certain other indebtedness in an amount greater than $250,000, our failure to obtain or maintain material governmental approvals, and a final judgment against us of at least $250,000. Further, if we are liquidated, the lender’s right to repayment would be senior to the rights of the holders of our common stock to receive any proceeds from the liquidation. The lenders could declare a default upon the occurrence of any event that they interpret as a material adverse change as defined under the loan and security agreement, thereby requiring us to repay the loan immediately or to attempt to reverse the declaration of default through negotiation or litigation. Any declaration by the lenders of an event of default could significantly harm our business and prospects and could cause the price of our common stock to decline.

If product liability lawsuits are brought against us, we may incur substantial liabilities and may be required to limit commercialization of our product candidates.

We face an inherent risk of product liability as a result of the clinical testing of our product candidates and will face an even greater risk if we commercialize any products. For example, we may be sued if our product candidates cause or are perceived to cause injury or are found to be otherwise unsuitable during clinical testing, manufacturing, marketing or sale. Any such product liability claims may include allegations of defects in manufacturing, defects in design, a failure to warn of dangers inherent in the product, negligence, strict liability or a breach of warranties. Claims could also be asserted under state consumer protection acts. If we cannot successfully defend ourselves against product liability claims, we may incur substantial liabilities or be required to limit commercialization of our product candidates. Even successful defense would require significant financial and management resources. Regardless of the merits or eventual outcome, liability claims may result in:

Our inability to obtain sufficient product liability insurance at an acceptable cost to protect against potential product liability claims could prevent or inhibit the commercialization of any products we develop, alone or with corporate collaborators. We currently carry $5 million of product liability insurance covering our clinical trials. Although we maintain such insurance, our insurance policies may have various exclusions, and we may be subject to a product liability claim for which we have no coverage. We may have to pay any amounts awarded by a court or negotiated in a settlement that exceed our coverage limitations or that are not covered by our insurance, and we may not have, or be able to obtain, sufficient capital to pay such amounts. Even if our agreements with any future corporate collaborators entitle us to indemnification against losses, such indemnification may not be available or adequate should any claim arise.

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Negative public opinion and increased regulatory scrutiny of gene therapy and genetic research may damage public perception of our product candidates or adversely affect our ability to conduct our business or obtain regulatory approvals for our product candidates.

Public perception may be influenced by claims that gene therapy is unsafe, and gene therapy may not gain the acceptance of the public or the medical community. In particular, our success will depend upon physicians specializing in the treatment of those diseases that our product candidates target prescribing treatments that involve the use of our product candidates in lieu of, or in addition to, existing treatments with which they are already familiar with and for which greater clinical data may be available. More restrictive government regulations or negative public opinion would have a negative effect on our business or financial condition and may delay or impair the development and commercialization of our product candidates or demand for any products we may develop. Adverse events in our clinical trials, even if not ultimately attributable to our product candidates, and the resulting publicity could lead to increased governmental regulation, unfavorable public perception, potential regulatory delays in the testing or approval of our potential product candidates, stricter labeling requirements for those product candidates that are approved and a decrease in demand for any such product candidates. Concern about environmental spread of our product, whether real or anticipated, may hinder the commercialization of our products.

Our internal computer systems, or those used by our CROs, SaaS providers, contractors or consultants, may fail or suffer security breaches.

Despite the implementation of security measures, our internal computer systems and those of our CROs, SaaS providers, contractors and consultants are vulnerable to damage from computer viruses and unauthorized access. While we have not experienced any such material system failure or security breach to date, if such an event were to occur and cause interruptions in our operations, it could result in a material disruption of our development programs and our business operations. For example, the loss of clinical trial data from completed or future clinical trials could result in delays in our regulatory approval efforts and significantly increase our costs to recover or reproduce the data. To the extent that any disruption or security breach were to result in a loss of, or damage to, our data or applications, or inappropriate disclosure of confidential or proprietary information, we could incur liability, and the further development and commercialization of our product candidates could be delayed.

Business disruptions could seriously harm our future revenue and financial condition and increase our costs and expenses.

Our operations, and those of our CROs, contractors and consultants, could be subject to power shortages, telecommunications failures, wildfires, water shortages, floods, earthquakes, hurricanes, typhoons, fires, extreme weather conditions, medical epidemics and other natural or man-made disasters or business interruptions for which we are predominantly self-insured. The occurrence of any of these business disruptions could seriously harm our operations and financial condition and increase our costs and expenses. Our ability to obtain clinical supplies of our product candidates could be disrupted if the operations of our contract manufacturers or cell line storage facilities are affected by a man-made or natural disaster or other business interruption.

Risks related to government regulation

The FDA may disagree with our regulatory plans, and we may fail to obtain regulatory approval of our product candidates.

Following receipt of Breakthrough Therapy Designation from the FDA, we redesigned our Phase 2/3 clinical trial of Toca 511 & Toca FC for the treatment of recurrent HGG to a single Phase 3 trial design and have included the 187 patients that were previously enrolled in the Phase 2/3 trial in the total of 380 patients expected to enroll in the redesigned trial. The interim or final analyses of this trial alone could support approval of a BLA for Toca 511 & Toca FC in the indication of recurrent HGG. However, the general approach for FDA approval of a new biologic or drug is to require dispositive data from two adequate and well-controlled Phase 3 clinical trials of the biologic or drug in the relevant patient population.

In addition, we believe that it is likely that there may be a regulatory requirement for one or more diagnostic assays to monitor treatment, especially for the presence of Toca 511 & Toca FC or their components or derivatives. We plan to meet with the FDA to discuss the development of such assays, and it is possible that the FDA may require a separate regulatory approval for such assays contemporaneously with the approval of Toca 511 & Toca FC.

Our clinical trials results may not support approval. In addition, Toca 511 & Toca FC and our other product candidates could fail to receive regulatory approval for many reasons, including the following:

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Obtaining and maintaining regulatory approval of our product candidates in one jurisdiction does not mean that we will be successful in obtaining regulatory approval of our product candidates in other jurisdictions.

Obtaining and maintaining regulatory approval of our product candidates in one jurisdiction does not guarantee that we will be able to obtain or maintain regulatory approval in any other jurisdiction, while a failure or delay in obtaining regulatory approval in one jurisdiction may have a negative effect on the regulatory approval process in others. For example, even if the FDA grants marketing approval of a product candidate, comparable regulatory authorities in foreign jurisdictions must also approve the manufacturing, marketing and promotion of the product candidate in those countries. Approval procedures vary among jurisdictions and can involve requirements and administrative review periods different from, and greater than, those in the United States, including additional preclinical studies or clinical trials. Studies and clinical trials conducted in one jurisdiction or study group may not be accepted by regulatory authorities in other jurisdictions. In many jurisdictions outside the United States, a product candidate must be approved for reimbursement before it can be approved for sale in that jurisdiction. In some cases, the price that we intend to charge for our products is also subject to approval.

We may also submit marketing applications in other countries. Regulatory authorities in jurisdictions outside of the United States have requirements for approval of product candidates with which we must comply prior to marketing in those jurisdictions. Obtaining approvals in one jurisdiction does not guarantee that we will be able to obtain approval in any other jurisdiction, but the failure to obtain approval in a jurisdiction may have a negative impact on our ability to obtain approval in other jurisdictions. Obtaining foreign regulatory approvals and compliance with foreign regulatory requirements could result in significant delays, difficulties and costs for us and could delay or prevent the introduction of our products in certain countries. If we fail to comply with the regulatory requirements in international markets and/or receive applicable marketing approvals, our target market will be reduced and our ability to realize the full market potential of our product candidates will be harmed.

Additional time may be required to obtain regulatory approval for Toca 511 & Toca FC because it is a combination product.

We believe our Toca 511 & Toca FC product candidate is regulated as a drug/biologic combination product, which will require coordination within the FDA and similar foreign regulatory agencies for review of their biologic and drug components and potentially one or more diagnostic assays to monitor treatment. Although the FDA and similar foreign regulatory agencies have systems in place for the review and approval of combination products such as ours, we may experience delays in the development and commercialization of our product candidates due to regulatory timing constraints and uncertainties in the product development and approval process.

Even if we receive regulatory approval of our product candidates, we will be subject to ongoing regulatory obligations and continued regulatory review, which may result in significant additional expense, and we may be subject to penalties and/or withdrawal of product approval if we fail to comply with regulatory requirements or experience unanticipated problems with our product candidates.

Any regulatory approvals that we receive for our product candidates will require surveillance to monitor the safety and efficacy of the product candidate. Specifically, we believe that it is likely that there may be a regulatory requirement for one or more diagnostic assays to monitor treatment, especially for the presence of Toca 511 or Toca FC or their components or derivatives. We plan to meet with the FDA to discuss the development of such assays, and it is possible that the FDA may require a separate regulatory approval for such assays. Further, each vector containing a particular gene could be regulated as a separate biologic depending on its intended use and FDA policy. The FDA may also require a REMS, in order to approve our product candidates, which could entail requirements for a medication guide, physician communication plans or additional elements to ensure safe use, such as restricted distribution methods, patient registries and other risk minimization tools. In addition, if the FDA or a comparable foreign regulatory authority approves our product candidates, the manufacturing processes, labeling, packaging, distribution, adverse event reporting, storage, advertising, promotion, import, export and record keeping for our product candidates will be subject to extensive and ongoing regulatory requirements. These requirements include, among other things, submissions of safety and other post-marketing information and

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reports, registration, as well as continued compliance with cGMPs for manufacturing and GCPs for any clinical trials that we conduct post-approval. Later discovery of previously unknown problems with our product candidates, including adverse events of unanticipated severity or frequency, or with our third-party manufacturers or manufacturing processes, or failure to comply with regulatory requirements, may result in, among other things:

The FDA’s and other regulatory authorities’ policies may change and additional government regulations may be enacted that could prevent, limit or delay regulatory approval of our product candidates. We cannot predict the likelihood, nature or extent of government regulation that may arise from future legislation or administrative action, either in the United States or abroad.

We have Orphan-Drug Designation for Toca 511 & Toca FC for the treatment of malignant glioma in addition to glioblastoma multiforme, or GBM, but we may be unable to maintain the benefits associated with Orphan-Drug Designation, including potential eligibility for any future market exclusivity.

Under the Orphan-Drug Act, the FDA may grant orphan designation to a drug or biologic intended to treat a rare disease or condition, which is defined as one occurring in a patient population of fewer than 200,000 in the United States, or a patient population greater than 200,000 in the United States for which there is no reasonable expectation that the cost of developing and making available in the United States a drug or biologic for a disease or condition will be recovered from sales in the United States for that drug or biologic. In the United States, Orphan-Drug Designation entitles a party to financial incentives such as opportunities for grant funding towards clinical trial costs, tax advantages and user-fee waivers. In addition, if a product that has Orphan-Drug Designation subsequently receives the first FDA approval for the disease for which it has such designation, the product is entitled to orphan product exclusivity, which means that the FDA may not approve any other applications to market the same biologic for the same indication for seven years, except in limited circumstances, such as a showing of clinical superiority to the product with orphan drug exclusivity or where the manufacturer is unable to assure sufficient product quantity.

Toca 511 & Toca FC has Orphan-Drug Designation in the United States for the treatment of malignant glioma in addition to GBM. However, we are currently developing this product candidate for the treatment of recurrent HGG, of which GBM is a subset. Exclusive marketing rights in the United States may be limited if we seek approval for an indication broader than the orphan designated indication and may be lost if the FDA later determines that the request for designation was materially defective or if the manufacturer is unable to assure sufficient quantities of the product to meet the needs of patients with the rare disease or condition. Further, even if we obtain orphan drug exclusivity for a product, that exclusivity may not effectively protect the product from competition because different products with different active moieties can be approved for the same condition. Even after an orphan product is approved, the FDA can subsequently approve the same product with the same active moiety for the same condition if the FDA concludes that the later product is safer, more effective or makes a major contribution to patient care. Orphan-Drug Designation neither shortens the development time or regulatory review time of a drug or biologic nor gives the drug or biologic any advantage in the regulatory review or approval process. In addition, while we may seek orphan designation for other product candidates, we may never receive such designations.

A Fast Track Designation or Breakthrough Therapy Designation by the FDA or PRIME Designation by the EMA, may not actually lead to a faster development or regulatory review or approval process.

If a product candidate is intended for the treatment of a serious or life-threatening condition and demonstrates the potential to address unmet medical needs for this condition, the drug sponsor may apply for FDA Fast Track Designation. Similarly, Breakthrough Therapy Designation may be granted by the FDA, or PRIME Designation may be granted by the EMA, to product candidates for serious conditions that have preliminary clinical evidence indicating the product candidate may offer substantial improvement over available therapy. The FDA and EMA have broad discretion whether or not to grant these designations, and even if we believe a particular product candidate is eligible for these designations, we cannot assure you that the FDA or EMA would decide to grant them. We have been granted Fast Track Designation and Breakthrough Therapy Designation for our Toca 511 & Toca FC product candidate for the treatment of recurrent HGG and PRIME designation for Toca 511 in glioma, but this is no assurance we will receive these designations for any future product candidates.  Further, even though we have received these designations for Toca 511 & Toca FC, we may not experience a faster development process, review or approval compared to conventional FDA or EMA procedures. The FDA or EMA may withdraw these designations if it believes that they are no longer supported by data from our clinical development program.

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Our Toca 511 & Toca FC product may face competition sooner than anticipated, if approved.

The Biologics Price Competition and Innovation Act, or BPCIA, created an abbreviated approval pathway for biological products that are biosimilar to or interchangeable with an FDA-licensed reference biological product. Under the BPCIA, an application for a biosimilar product may not be submitted to the FDA until four years following the date that the reference product was first licensed by the FDA. In addition, the approval of a biosimilar product may not be made effective by the FDA until 12 years from the date on which the reference product was first licensed. During this 12-year period of exclusivity, another company may still market a competing version of the reference product if the FDA approves a full BLA for the competing product containing the sponsor’s own preclinical data and data from adequate and well-controlled clinical trials to demonstrate the safety, purity and potency of its product.

We believe that any of our product candidates approved as a biological product under a BLA should qualify for the 12-year period of exclusivity. However, there is a risk that this exclusivity could be shortened due to congressional action or otherwise, or that the FDA will not consider our product candidates to be reference products for competing products, potentially creating the opportunity for competition sooner than anticipated. Other aspects of the BPCIA, some of which may impact the BPCIA exclusivity provisions, have also been the subject of recent litigation. Moreover, the extent to which a biosimilar, once approved, will be substituted for any one of our reference products in a way that is similar to traditional generic substitution for non-biological products is not yet clear, and will depend on a number of marketplace and regulatory factors that are still developing.

We may be subject, directly or indirectly, to federal and state healthcare fraud and abuse laws, false claims laws, privacy laws and other federal and state healthcare laws, and the failure to comply with such laws could result in substantial penalties. Our employees, independent contractors, consultants, principal investigators, CROs, commercial partners and vendors may engage in misconduct or other improper activities, including noncompliance with regulatory standards and requirements.

We are exposed to the risk of fraud, misconduct or other illegal activity by our employees, independent contractors, consultants, principal investigators, CROs, commercial partners and vendors. Misconduct by these parties could include intentional, reckless and/or negligent conduct that fails to: comply with the laws of the FDA and other similar foreign regulatory bodies; provide true, complete and accurate information to the FDA and other similar foreign regulatory bodies; comply with manufacturing standards we have established; comply with federal and state data privacy, security, fraud and abuse and other healthcare laws and regulations in the United States and similar foreign fraudulent misconduct laws; or report financial information or data accurately or to disclose unauthorized activities to us.

In addition, our current and future operations are subject to regulation under such laws, and if we obtain FDA approval for any of our product candidates and begin commercializing those products in the United States, our potential exposure under such laws would increase significantly, along with our costs associated with compliance with such laws. These laws may impact, among other things, our current activities with principal investigators and research patients, as well as proposed and future sales, marketing and education programs. In particular, the promotion, sales and marketing of healthcare items and services, as well as certain business arrangements in the healthcare industry, are subject to extensive laws and regulations intended to prevent fraud, misconduct, kickbacks, self-dealing and other abusive practices. These laws and regulations may restrict or prohibit a wide range of pricing, discounting, marketing and promotion, including off-label promotion of our products, structuring of commission(s), certain customer incentive programs and other business arrangements generally. Activities subject to these laws also involve the improper use or misrepresentation of information obtained in the course of patient recruitment for clinical trials, creating fraudulent data in our preclinical studies or clinical trials or illegal misappropriation of drug product, which could result in regulatory sanctions and cause serious harm to our reputation. The laws that may affect our ability to operate include, but are not limited to:

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Additionally, we are subject to state and foreign equivalents of each of the healthcare fraud and abuse laws described above, among others, some of which may be broader in scope and may apply regardless of the payor. We may also be subject to state and foreign laws that require pharmaceutical companies to comply with the pharmaceutical industry’s voluntary compliance guidelines and the relevant compliance guidance promulgated by the federal government or otherwise restrict payments that may be made to healthcare providers; and to report information related to payments and other transfers of value to physicians and other healthcare providers or marketing expenditures. We may also be subject to state and foreign laws governing the privacy and security of health information in certain circumstances, many of which differ from each other in significant ways and often are not preempted by HIPAA, thus complicating compliance efforts. In the European Union, Directive 95/46/EC (as amended) applies to identified or identifiable personal data processed by automated means and data contained in, or intended to be part of, non-automated filing systems as well as the transfer of such data to a country outside of the European Economic Area.  Effective as of May 25, 2018, Directive 95/46/EC will be replaced by the European Union’s General Data Protection Regulation (2016/679), or GDPR.  Under the GDPR, fines of up to 20 million Euros or up to 4% of the annual global turnover of the infringer, whichever is greater, could be imposed for significant non-compliance.

It is not always possible to identify and deter employee misconduct, and the precautions we take to detect and prevent inappropriate conduct may not be effective in controlling unknown or unmanaged risks or losses or in protecting us from governmental investigations or other actions or lawsuits stemming from a failure to be in compliance with such laws or regulations. We are also subject to the risk that a person or government could allege such fraud or other misconduct, even if none occurred. Efforts to ensure that our business arrangements will comply with applicable healthcare laws and regulations will involve substantial costs. It is possible that governmental and enforcement authorities will conclude that our business practices may not comply with current or future statutes, regulations or case law interpreting applicable fraud and abuse or other healthcare laws and regulations. If any such actions are instituted against us, and we are not successful in defending ourselves or asserting our rights, those actions could have a significant impact on our business, including the imposition of civil, criminal and administrative penalties, damages, disgorgement, monetary fines, possible exclusion from participation in Medicare, Medicaid and other federal healthcare programs, contractual damages, reputational harm, diminished profits and future earnings, individual imprisonment, additional reporting obligations and oversight if we become subject to a corporate integrity agreement or other agreement to resolve allegations of non-compliance with these laws, and curtailment or restructuring of our operations, any of which could adversely affect our ability to operate our business and our results of operations. In addition, the approval and commercialization of any of our product candidates outside the United States will also likely subject us to foreign equivalents of the healthcare laws mentioned above, among other foreign laws.

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Coverage and reimbursement may be limited or unavailable in certain market segments for our product candidates, if approved, which could make it difficult for us to sell our product candidates profitably.

Successful sales of our product candidates, if approved, depend on the availability of coverage and adequate reimbursement from third-party payors. Because our product candidates represent new approaches to the treatment of cancer, we cannot be sure that coverage and reimbursement will be available for, or accurately estimate the potential revenue from, our product candidates.

Patients who are provided medical treatment for their conditions generally rely on third-party payors to reimburse all or part of the costs associated with their treatment. Coverage and adequate reimbursement from governmental healthcare programs, such as Medicare and Medicaid, and commercial payors are critical to new product acceptance.

Government authorities and other third-party payors, such as private health insurers and health maintenance organizations, decide which drugs and treatments they will cover and the amount of reimbursement. Coverage and reimbursement by a third-party payor may depend upon a number of factors, including, but not limited to, the third-party payor’s determination that use of a product is:

In the United States, no uniform policy of coverage and reimbursement for products exists among third-party payors, and coverage and reimbursement for products can differ significantly from payor to payor. As a result, obtaining coverage and reimbursement approval of a product from a government or other third-party payor is a time-consuming and costly process that could require us to provide to each payor supporting scientific, clinical and cost-effectiveness data for the use of our products and to justify the level of coverage and reimbursement relative to other therapies, with no assurance that coverage and adequate reimbursement will be obtained. Third party payors may also have difficulty in determining the appropriate coverage of our product candidates, if approved, due to the fact that they are combination products that include a small molecule drug. To the extent there are any delays in determining such coverage or inadequate coverage and reimbursement for all aspects of our combination therapies, it would adversely affect the market acceptance, demand and use of our product candidates.

A number of gene therapy products have been approved over the past year by the FDA. Although the Center for Medicare and Medicaid Services, or CMS, subsequently approved its first method of coverage and reimbursement for one such product, the methodology has been subject to challenge by members of Congress. Often private payors follow the coverage and reimbursement decisions of the Medicare program, and it is difficult to predict how CMS may decide to cover and reimburse our product candidates, if approved, and those determinations are subject to change. Any denial in coverage or reduction in reimbursement from Medicare or other government programs may result in a similar denial or reduction in payments from private payors, which may adversely affect our future profitability.

We intend to seek approval to market our product candidates in both the United States and in selected foreign jurisdictions. If we obtain approval in one or more foreign jurisdictions for our product candidates, we will be subject to rules and regulations in those jurisdictions. In some foreign countries, particularly those in the European Union, the pricing of biologics is subject to governmental control and other market regulations which could put pressure on the pricing and usage of our product candidates. In these countries, pricing negotiations with governmental authorities can take considerable time after obtaining marketing approval of a product candidate. In addition, market acceptance and sales of our product candidates will depend significantly on the availability of coverage and adequate reimbursement from third-party payors for our product candidates and may be affected by existing and future health care reform measures.

Healthcare legislative reform measures may have a material adverse effect on our business and results of operations.

Third-party payors, whether domestic or foreign, or governmental or commercial, are developing increasingly sophisticated methods of controlling healthcare costs. In both the United States and certain foreign jurisdictions, there have been a number of legislative and regulatory changes to the health care system that could impact our ability to sell our products profitably. In particular, in 2010, the Affordable Care Act was enacted in the United States. The Affordable Care Act and its implementing regulations, among other things, subjected biological products to potential competition by lower-cost biosimilars, revised the methodology by which rebates owed by manufacturers to the state and federal government for covered outpatient drugs and certain biologics, including our product candidates, under the Medicaid Drug Rebate Program are calculated, increased the minimum Medicaid rebates owed by most manufacturers under the Medicaid Drug Rebate Program, extended the Medicaid Drug Rebate program to utilization of prescriptions of individuals enrolled in Medicaid managed care organizations, subjected manufacturers to new annual fees and taxes for certain branded prescription drugs, and provided incentives to programs that increase the federal government’s comparative effectiveness research.

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Since its enactment, there have been judicial and Congressional challenges to certain aspects of the Affordable Care Act, and we expect there will be additional challenges and amendments to the Affordable Care Act in the future, as well as recent efforts by the Trump administration to repeal or replace certain aspects of the Affordable Care Act.  Since January 2017, President Trump has signed two Executive Orders and other directives designed to delay the implementation of any certain provisions of the Affordable Care Act or otherwise circumvent some of the requirements for health insurance mandated by the Affordable Care Act. Concurrently, Congress has considered legislation that would repeal or repeal and replace all or part of the Affordable Care Act. While Congress has not passed comprehensive repeal legislation, two bills affecting the implementation of certain taxes under the Affordable Care Act have been signed into law. The Tax Cuts and Jobs Act of 2017 includes a provision repealing, effective January 1, 2019, the tax-based shared responsibility payment imposed by the Affordable Care Act on certain individuals who fail to maintain qualifying health coverage for all or part of a year that is commonly referred to as the “individual mandate”. Additionally, on January 22, 2018, President Trump signed a continuing resolution on appropriations for fiscal year 2018 that delayed the implementation of certain Affordable Care Act-mandated fees, including the so-called “Cadillac” tax on certain high cost employer-sponsored insurance plans, the annual fee imposed on certain health insurance providers based on market share, and the medical device excise tax on non-exempt medical devices. Further, the Bipartisan Budget Act of 2018, or the BBA, among other things, amends the Affordable Care Act, effective January 1, 2019, to close the coverage gap in most Medicare Part D drug plans, commonly referred to as the “donut hole”. Congress will likely consider other legislation to replace elements of the Affordable Care Act.  We continue to evaluate the effect that the Affordable Care Act and its possible repeal and replacement has on our business. It is uncertain the extent to which any such changes may impact our business or financial condition.

In addition, other legislative changes have been proposed and adopted in the United States since the Affordable Care Act was enacted. In August 2011, the Budget Control Act of 2011, among other things, created measures for spending reductions by Congress. A Joint Select Committee on Deficit Reduction, tasked with recommending a targeted deficit reduction of at least $1.2 trillion for the years 2013 through 2021, was unable to reach required goals, thereby triggering the legislation’s automatic reduction to several government programs. This includes aggregate reductions of Medicare payments to providers up to 2% per fiscal year, which went into effect on April 1, 2013 and, due to subsequent legislation, including the BBA, will stay in effect through 2027 unless Congressional action is taken. In January 2013, President Obama signed into law the American Taxpayer Relief Act of 2012, which, among other things, reduced Medicare payments to several providers, including hospitals, imaging centers and cancer treatment centers, and increased the statute of limitations period for the government to recover overpayments to providers from three to five years. Moreover, payment methodologies including payment for any companion diagnostics may be subject to changes in healthcare legislation and regulatory initiatives. For example, CMS began bundling the Medicare payments for certain laboratory tests ordered while a patient received services in a hospital outpatient setting and, beginning in 2018, CMS will pay for clinical laboratory services based on a weighted-average of reported prices that private payors, Medicare Advantage plans and Medicaid Managed Care plans pay for laboratory services.

Further recently, there has been heightened governmental scrutiny over the manner in which drug manufacturers set prices for their marketed products, which has resulted in several Congressional inquiries and proposed and enacted federal and state legislation designed to, among other things, bring more transparency to product pricing, review the relationship between pricing and manufacturer patient programs, and reform government program reimbursement methodologies for drug products. At the federal level, the Trump administration’s budget proposal for fiscal year 2019 contains further product price control measures that could be enacted during the 2019 budget process or in other future legislation, including, for example, measures to permit Medicare Part D plans to negotiate the price of certain products under Medicare Part B, to allow some states to negotiate product prices under Medicaid, and to eliminate cost sharing for generic products for low-income patients. While any proposed measures will require authorization through additional legislation to become effective, Congress and the Trump administration have each indicated that it will continue to seek new legislative and/or administrative measures to control drug costs. At the state level, legislatures are increasingly passing legislation and implementing regulations designed to control pharmaceutical and biological product pricing, including price or patient reimbursement constraints, discounts, restrictions on certain product access and marketing cost disclosure and transparency measures, and, in some cases, designed to encourage importation from other countries and bulk purchasing.

There have been, and likely will continue to be, legislative and regulatory proposals at the foreign, federal and state levels directed at broadening the availability of healthcare and containing or lowering the cost of healthcare. We cannot predict the initiatives that may be adopted in the future. The continuing efforts of the government, insurance companies, managed care organizations and other payors of healthcare services to contain or reduce costs of healthcare and/or impose price controls may adversely affect:

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Due to the novel nature of our technology and the small size of our initial target patient populations, we face uncertainty related to pricing and reimbursement for these product candidates.

Our initial target patient populations are relatively small. As a result, the pricing and reimbursement of our product candidates, if approved, must be adequate to support commercial infrastructure. If we are unable to obtain adequate levels of reimbursement, our ability to successfully market and sell our product candidates will be adversely affected. The manner and level at which reimbursement is provided for services related to our product candidates (e.g., for administration of our product to patients) is also important. Inadequate reimbursement for such services may lead to physician resistance and adversely affect our ability to market or sell our products.

We and our contract manufacturers are subject to significant regulation with respect to manufacturing our products. The manufacturing facilities on which we rely may not continue to meet regulatory requirements and have limited capacity.

We currently have relationships with a limited number of suppliers for the manufacturing of our viral vectors and product candidates. Each supplier may require licenses to manufacture such components if such processes are not owned by the supplier or in the public domain and we may be unable to transfer or sublicense the intellectual property rights we may have or later obtain with respect to such activities.

All entities involved in the preparation of therapeutics for clinical trials or commercial sale, including our existing contract manufacturers for our product candidates, are subject to extensive regulation. Components of a finished therapeutic product approved for commercial sale or used in late-stage clinical trials must be manufactured in accordance with cGMP. These regulations govern manufacturing processes and procedures (including record keeping) and the implementation and operation of quality systems to control and assure the quality of investigational products and products approved for sale. Poor control of production processes can lead to the introduction of adventitious agents or other contaminants, or to inadvertent changes in the properties or stability of our product candidates that may not be detectable in final product testing. We or our contract manufacturers must supply all necessary documentation in support of a BLA on a timely basis and must adhere to the FDA’s good laboratory practices and cGMP regulations enforced by the FDA through its facilities inspection program. Some of our contract manufacturers have not produced a commercially-approved product and therefore may have not obtained the requisite FDA approvals to do so. Our facilities and quality systems and the facilities and quality systems of some or all of our third-party contractors must pass a pre-approval inspection for compliance with the applicable regulations as a condition of regulatory approval of our product candidates or any of our other potential products. In addition, the regulatory authorities may, at any time, audit or inspect a manufacturing facility involved with the preparation of our product candidates or our other potential products or the associated quality systems for compliance with the regulations applicable to the activities being conducted. If these facilities do not pass a pre-approval plant inspection, FDA approval of the products may not be granted.

The regulatory authorities also may, at any time following approval of a product for sale, audit our manufacturing facilities or those of our third-party contractors. If any such inspection or audit identifies a failure to comply with applicable regulations or if a violation of our product specifications or applicable regulations occurs independent of such an inspection or audit, we or the relevant regulatory authority may require remedial measures that may be costly and/or time-consuming for us or a third party to implement and that may include the temporary or permanent suspension of a clinical trial or commercial sales or the temporary or permanent closure of a facility. Any such remedial measures imposed upon us or third parties with whom we contract could materially harm our business.

If we or any of our third-party manufacturers fail to maintain regulatory compliance, the FDA can impose regulatory sanctions including, among other things, refusal to approve a pending application for a new drug product or biologic product or revocation of a pre-existing approval. As a result, our business, financial condition and results of operations may be materially harmed.

Additionally, if supply from one approved manufacturer is interrupted, there could be a significant disruption in commercial supply. An alternative manufacturer would need to be qualified through a BLA supplement which could result in further delay. The regulatory agencies may also require additional studies if a new manufacturer is relied upon for commercial production. Switching manufacturers may involve substantial costs and is likely to result in a delay in our desired clinical and commercial timelines.

These factors could cause the delay of clinical trials, regulatory submissions, required approvals or commercialization of our product candidates, cause us to incur higher costs and prevent us from commercializing our products successfully. Furthermore, if our suppliers fail to meet contractual requirements, and we are unable to secure one or more replacement suppliers capable of production at a substantially equivalent cost, our clinical trials may be delayed or we could lose potential revenue.

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If we fail to comply with environmental, health and safety laws and regulations, we could become subject to fines or penalties or incur costs that could have a material adverse effect on the success of our business.

Our research and development, manufacturing processes, clinical trials and products may involve the controlled use of hazardous materials, chemicals, viruses and various radioactive compounds. Specifically, if our products or product candidates spread from human or companion pet patients to other people or pets, these other individuals or pets (such as the immune suppressed or the very young), might be more sensitive to the product or product candidate than the patient and may experience an adverse reaction. We are subject to federal, state and local laws and regulations governing the use, manufacture, storage, handling and disposal of such materials and certain waste products, including numerous environmental, health and safety laws and regulations, such as those governing laboratory procedures and the handling, use, storage, treatment and disposal of hazardous materials and wastes. Our operations involve the use of hazardous and flammable materials, including chemicals and biological materials. Our operations also produce hazardous waste products. We generally contract with third parties for the disposal of these materials and wastes. We cannot eliminate the risk of contamination or injury from these materials. In the event of contamination or injury resulting from our use of hazardous materials, we could be held liable for any resulting damages, and any liability could exceed our resources. We also could incur significant costs associated with civil or criminal fines and penalties.

Although we maintain workers’ compensation insurance to cover us for costs and expenses we may incur due to injuries to our employees resulting from the use of hazardous materials or other work-related injuries, this insurance may not provide adequate coverage against potential liabilities. In addition, we may incur substantial costs in order to comply with current or future environmental, health and safety laws and regulations. These current or future laws and regulations may impair our research, development or production efforts. Failure to comply with these laws and regulations also may result in substantial fines, penalties or other sanctions.

Risks related to our intellectual property

If we are unable to protect our intellectual property rights or if our intellectual property rights are inadequate for our technology and product candidates, our competitive position could be harmed.

Our commercial success will depend in part on our ability to obtain and maintain patent and other intellectual property protection in the United States and other countries with respect to our proprietary technology and products. We rely on trade secret, patent, copyright and trademark laws, and confidentiality, licensing and other agreements with employees and third parties, all of which offer only limited protection. We seek to protect our proprietary position by filing and prosecuting patent applications in the United States and abroad related to our novel technologies and products that are important to our business.

The patent positions of biotechnology and pharmaceutical companies generally are highly uncertain, involve complex legal and factual questions and have in recent years been the subject of much litigation. As a result, the issuance, scope, validity, enforceability and commercial value of our patents, including those patent rights licensed to us by third parties, are highly uncertain. The steps we or our licensors have taken to protect our proprietary rights may not be adequate to preclude misappropriation of our proprietary information or infringement of our intellectual property rights, both inside and outside of the United States. Further, the examination process may require us or our licensors to narrow the claims for our pending patent applications, which may limit the scope of patent protection that may be obtained if these applications issue. The rights already granted under any of our currently issued patents or those licensed to us and those that may be granted under future issued patents may not provide us with the proprietary protection or competitive advantages we are seeking. If we or our licensors are unable to obtain and maintain patent protection for our technology and products, or if the scope of the patent protection obtained is not sufficient, our competitors could develop and commercialize technology and products similar or superior to ours, and our ability to successfully commercialize our technology and products may be adversely affected. It is also possible that we or our licensors will fail to identify patentable aspects of inventions made in the course of our development and commercialization activities before it is too late to obtain patent protection on them. It is also possible that as research and development progresses, the direction of our intellectual property strategy and patent portfolio will change, resulting in strategic business decisions to allow certain patents or patent applications to be abandoned or lapse.

With respect to patent rights, we do not know whether any of the pending patent applications for any of our compounds or biologic products will result in the issuance of patents that effectively protect our technology or products, or if any of our issued patents or if any of our or our licensors’ issued patents will effectively prevent others from commercializing competitive technologies and products. Publications of discoveries in the scientific literature often lag behind the actual discoveries, and patent applications in the United States and other jurisdictions are typically not published until 18 months after filing or in some cases not at all, until they are issued as a patent. Therefore, we cannot be certain that we or our licensors were the first to make the inventions claimed in our owned or licensed patents or pending patent applications, or that we or our licensors were the first to file for patent protection of such inventions.

Our pending applications cannot be enforced against third parties practicing the technology claimed in such applications unless and until a patent issues from such applications. Because the issuance of a patent is not conclusive as to its inventorship, scope, validity or enforceability, issued patents that we own or have licensed from third parties may be challenged in the courts or patent

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offices in the United States and abroad. Such challenges may result in the loss of patent protection, the narrowing of claims in such patents or the invalidity or unenforceability of such patents, which could limit our ability to stop others from using or commercializing similar or identical technology and products, or limit the duration of the patent protection for our technology and products. Protecting against the unauthorized use of our or our licensor’s patented technology, trademarks and other intellectual property rights is expensive, difficult and may in some cases not be possible. In some cases, it may be difficult or impossible to detect third-party infringement or misappropriation of our intellectual property rights, even in relation to issued patent claims, and proving any such infringement may be even more difficult.

Third-party claims of intellectual property infringement may prevent or delay our development and commercialization efforts.

Our commercial success depends in part on our avoiding infringement of the patents and proprietary rights of third parties. There is a substantial amount of litigation, both within and outside the United States, involving patent and other intellectual property rights in the biotechnology and pharmaceutical industries, including patent infringement lawsuits, interferences, oppositions and inter partes reexamination proceedings before the U.S. Patent and Trademark Office, or U.S. PTO, and corresponding foreign patent offices. Numerous U.S. and foreign issued patents and pending patent applications, which are owned by third parties, exist in the fields in which we are pursuing development candidates. As the biotechnology and pharmaceutical industries expand and more patents are issued, the risk increases that our product candidates may be subject to claims of infringement of the patent rights of third parties.

Third parties have asserted, and in the future may assert, that we are employing their proprietary technology without authorization. There may be third-party patents or patent applications with claims to materials, formulations, methods of manufacture or methods for treatment related to the use or manufacture of our product candidates. Because patent applications can take many years to issue, there may be currently pending patent applications which may later result in issued patents that our product candidates may infringe. In addition, third parties may obtain patents in the future and claim that use of our technologies infringes upon these patents. If any third-party patents were held by a court of competent jurisdiction to cover the manufacturing process of any of our product candidates, or any final product itself, the holders of any such patents may be able to block our ability to commercialize such product candidate unless we obtained a license under the applicable patents, or until such patents expire.

Similarly, if any third-party patents were held by a court of competent jurisdiction to cover aspects of our formulations, processes for manufacture or methods of use, including combination therapy, the holders of any such patents may be able to block our ability to develop and commercialize the applicable product candidate unless we obtained a license or until such patent expires. In either case, such a license may not be available on commercially reasonable terms or at all.

Parties making claims against us may obtain injunctive or other equitable relief, which could effectively block our ability to further develop and commercialize one or more of our product candidates. Defense of these claims, regardless of their merit, may involve substantial litigation expense and would be a substantial diversion of employee resources from our business. In the event of a successful claim of infringement against us, we may have to pay substantial damages, including treble damages and attorneys’ fees for willful infringement, pay royalties, redesign our infringing products or obtain one or more licenses from third parties, which may be impossible or require substantial time and monetary expenditure.

We may not be successful in obtaining or maintaining necessary rights to gene therapy product components and processes for our development pipeline through acquisitions and in-licenses.

Presently we believe that we have rights to the intellectual property, through licenses from third parties and under patents that we own, to develop our gene therapy product candidates. Because our programs may involve additional product candidates that may require the use of proprietary rights held by third parties, the growth of our business may depend in part on our ability to acquire, in-license or use these proprietary rights. In addition, our product candidates may require specific formulations to work effectively and efficiently and these rights may be held by others. We may be unable to acquire or in-license any compositions, methods of use, processes or other third-party intellectual property rights from third parties that we identify. The licensing and acquisition of third-party intellectual property rights is a competitive area, and a number of more established companies are also pursuing strategies to license or acquire third-party intellectual property rights that we may consider attractive. These established companies may have a competitive advantage over us due to their size, cash resources and greater clinical development and commercialization capabilities.

In addition, companies that perceive us to be a competitor may be unwilling to assign or license rights to us. We also may be unable to license or acquire third-party intellectual property rights on terms that would allow us to make an appropriate return on our investment. If we are unable to successfully obtain rights to required third-party intellectual property rights, our business, financial condition and prospects for growth could suffer.

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If we fail to comply with our obligations in the agreement under which we license intellectual property rights from the University of Southern California, or USC, or otherwise experience disruptions to our business relationships with USC or other future licensors, we could lose license rights that are important to our business.

In October 2007, we entered into a license agreement with USC pursuant to which we received a worldwide, exclusive license to, among other things, manufacture and market products utilizing certain inventions that are critical to our business. We expect to enter into additional license agreements in the future. Our existing license agreement imposes, and we expect that future license agreements will impose, various diligence, milestone payment, royalty and other obligations on us. If we fail to comply with our obligations under these agreements, or we are subject to a bankruptcy, the licensor may have the right to terminate the license, in which event we would not be able to market products covered by the license.

We may need to obtain licenses from third parties to advance our research or allow commercialization of our product candidates, and we have done so from time to time. We may fail to obtain any of these licenses at a reasonable cost or on reasonable terms, if at all. In that event, we may be required to expend significant time and resources to develop or license replacement technology. If we are unable to do so, we may be unable to develop or commercialize the affected product candidates, which could harm our business significantly. We cannot provide any assurances that third-party patents do not exist which might be enforced against our current product candidates or future products, resulting in either an injunction prohibiting our sales, or, with respect to our sales, an obligation on our part to pay royalties and/or other forms of compensation to third parties.

In certain cases, patent prosecution of our licensed technology may be controlled solely by the licensor. If our licensors fail to obtain and maintain patent or other protection for the proprietary intellectual property we license from them, we could lose our rights to the intellectual property or our exclusivity with respect to those rights, and our competitors could market competing products using the intellectual property. In certain cases, we control the prosecution of patents resulting from licensed technology. In the event we breach any of our obligations related to such prosecution, we may incur significant liability to our licensing partners. Licensing of intellectual property is of critical importance to our business and involves complex legal, business and scientific issues and is complicated by the rapid pace of scientific discovery in our industry. Disputes may arise regarding intellectual property subject to a licensing agreement, including:

If disputes over intellectual property that we have licensed prevent or impair our ability to maintain our current licensing arrangements on acceptable terms, we may be unable to successfully develop and commercialize the affected product candidates.

We may be involved in lawsuits to protect or enforce our patents or the patents of our licensors, which could be expensive, time-consuming and unsuccessful.

Competitors may infringe our patents or the patents of our licensors. To counter infringement or unauthorized use, we may be required to file infringement claims, which can be expensive and time-consuming. In addition, in an infringement proceeding, a court may decide that a patent of ours or our licensors is not valid, is unenforceable and/or is not infringed, or may refuse to stop the other party from using the technology at issue on the grounds that our patents do not cover the technology in question. An adverse result in any litigation or defense proceedings could put one or more of our patents at risk of being invalidated or interpreted narrowly and could put our patent applications at risk of not issuing.

Interference or derivation proceedings provoked by third parties or brought by us may be necessary to determine the priority of inventions with respect to our patents or patent applications or those of our licensors. An unfavorable outcome could require us to cease using the related technology or to attempt to license rights to it from the prevailing party. Our business could be harmed if the prevailing party does not offer us a license on commercially reasonable terms. Our defense of litigation, interference or derivation proceedings may fail and, even if successful, may result in substantial costs and distract our management and other employees. We may not be able to prevent, alone or with our licensors, misappropriation of our intellectual property rights, particularly in countries where the laws may not protect those rights as fully as in the United States.

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Furthermore, because of the substantial amount of discovery required in connection with intellectual property litigation, there is a risk that some of our confidential information could be compromised by disclosure during this type of litigation. There could also be public announcements of the results of hearings, motions or other interim proceedings or developments. If securities analysts or investors perceive these results to be negative, it could have a material adverse effect on the price of our common stock.

Obtaining and maintaining our patent protection depends on compliance with various procedural, document submission, fee payment and other requirements imposed by governmental patent agencies, and our patent protection could be reduced or eliminated for non-compliance with these requirements.

Periodic maintenance fees, renewal fees, annuity fees and various other governmental fees on patents and/or applications will be due to be paid to the U.S. PTO and various governmental patent agencies outside of the United States in several stages over the lifetime of the patents and/or applications. We employ an outside firm and rely on our outside counsel to pay these fees due to non-U.S. patent agencies. The U.S. PTO and various non-U.S. governmental patent agencies require compliance with a number of procedural, documentary, fee payment and other similar provisions during the patent application process. We employ reputable law firms and other professionals to help us comply, and in many cases, an inadvertent lapse can be cured by payment of a late fee or by other means in accordance with the applicable rules. However, there are situations in which non-compliance can result in abandonment or lapse of the patent or patent application, resulting in partial or complete loss of patent rights in the relevant jurisdiction. In such an event, our competitors might be able to enter the market and this circumstance would have a material adverse effect on our business.

Issued patents covering our product candidates could be found invalid or unenforceable if challenged in court.

If we, the University of Southern California, or USC, or one of our future licensing partners initiated legal proceedings against a third party to enforce a patent covering one of our product candidates, the defendant could counterclaim that the patent covering our product candidate is invalid and/or unenforceable. In patent litigation in the United States, defendant counterclaims alleging invalidity and/or unenforceability are commonplace. Grounds for a validity challenge could be an alleged failure to meet any of several statutory requirements, including lack of novelty, obviousness or non-enablement. Grounds for an unenforceability assertion could be an allegation that someone connected with prosecution of the patent withheld relevant information from the U.S. PTO, or made a misleading statement, during prosecution. Third parties may also raise similar claims before administrative bodies in the United States or abroad, even outside the context of litigation. Such mechanisms include re-examination, post grant review and equivalent proceedings in foreign jurisdictions (e.g., opposition proceedings). Such proceedings could result in revocation or amendment to our patents in such a way that they no longer cover our product candidates. The outcome following legal assertions of invalidity and unenforceability is unpredictable. With respect to the validity question, for example, we cannot be certain that there is no invalidating prior art, of which we and the patent examiner were unaware during prosecution. If a defendant were to prevail on a legal assertion of invalidity and/or unenforceability, we would lose at least part, and perhaps all, of the patent protection on our product candidates. Such a loss of patent protection would have a material adverse impact on our business.

We may be subject to claims that our employees, consultants or independent contractors have wrongfully used or disclosed confidential information of third parties or that our employees have wrongfully used or disclosed alleged trade secrets of their former employers.

We employ individuals who were previously employed at universities or other biotechnology or pharmaceutical companies, including our competitors or potential competitors. Although we try to ensure that our employees, consultants and independent contractors do not use the proprietary information or know-how of others in their work for us, we may be subject to claims that we or our employees, consultants or independent contractors have inadvertently or otherwise used or disclosed intellectual property, including trade secrets or other proprietary information, of any of our employee’s former employer or other third parties. Litigation may be necessary to defend against these claims. If we fail in defending any such claims, in addition to paying monetary damages, we may lose valuable intellectual property rights or personnel, which could adversely impact our business. Even if we are successful in defending against such claims, litigation could result in substantial costs and be a distraction to management and other employees.

We may be subject to claims challenging the inventorship or ownership of our patents and other intellectual property.

We may be subject to claims that former employees, collaborators or other third parties have an ownership interest in our patents or other intellectual property. We may have potential ownership disputes arising, for example, from conflicting obligations of consultants, collaborators or others who are involved in developing our product candidates. Litigation may be necessary to defend against these and other claims challenging inventorship or ownership. If we fail in defending any such claims, in addition to paying monetary damages, we may lose valuable intellectual property rights, such as exclusive ownership of, or right to use, valuable intellectual property. Such an outcome could have a material adverse effect on our business. Even if we are successful in defending against such claims, litigation could result in substantial costs and be a distraction to management and other employees.

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Changes in U.S. patent law could diminish the value of patents in general, thereby impairing our ability to protect our products.

As is the case with other biotechnology companies, our success is heavily dependent on intellectual property, particularly patents. Obtaining and enforcing patents in the biotechnology industry involve both technological and legal complexity, and therefore obtaining and enforcing biotechnology patents is costly, time-consuming and inherently uncertain. In addition, the United States has recently enacted and is currently implementing wide-ranging patent reform legislation. Recent U.S. Supreme Court rulings have narrowed the scope of patent protection available in certain circumstances and weakened the rights of patent owners in certain situations. In addition to increasing uncertainty with regard to our ability to obtain patents in the future, this combination of events has created uncertainty with respect to the value of patents, once obtained. Depending on decisions by the U.S. Congress, the federal courts and the U.S. PTO, the laws and regulations governing patents could change in unpredictable ways that would weaken our ability to obtain new patents or to enforce our existing patents and patents that we might obtain in the future.

We have not yet registered trademarks for a commercial trade name for Toca 511 & Toca FC, and failure to secure such registrations could adversely affect our business.

We have not yet developed a proprietary name for our products nor registered trademarks for a commercial trade name for Toca 511 & Toca FC. During trademark registration proceedings, we may receive rejections. Although we would be given an opportunity to respond to those rejections, we may be unable to overcome such rejections. In addition, in the U.S. PTO and in comparable agencies in many foreign jurisdictions, third parties are given an opportunity to oppose pending trademark applications and to seek to cancel registered trademarks. Opposition or cancellation proceedings may be filed against our trademarks, and our trademarks may not survive such proceedings. Moreover, any name we propose to use with our product candidates in the United States must be approved by the FDA, regardless of whether we have registered it, or applied to register it, as a trademark. The FDA typically conducts a review of proposed product names, including an evaluation of potential for confusion with other product names. If the FDA objects to any of our proposed proprietary product names, we may be required to expend significant additional resources in an effort to identify a suitable substitute name that would qualify under applicable trademark laws, not infringe the existing rights of third parties and be acceptable to the FDA.

We may not be able to protect our intellectual property rights throughout the world.

Filing, prosecuting and defending patents on product candidates in all countries throughout the world would be prohibitively expensive, and our intellectual property rights in some countries outside the United States can be less extensive than those in the United States. In addition, the laws of some foreign countries do not protect intellectual property rights to the same extent as federal and state laws in the United States. Consequently, we may not be able to prevent third parties from practicing our inventions in all countries outside the United States, or from selling or importing products made using our inventions in and into the United States or other jurisdictions. Competitors may use our technologies in jurisdictions where we have not obtained patent protection to develop their own products and further, may export otherwise infringing products to territories where we have patent protection, but enforcement is not as strong as that in the United States. These products may compete with our products and our patents or other intellectual property rights may not be effective or sufficient to prevent them from competing.

Many companies have encountered significant problems in protecting and defending intellectual property rights in foreign jurisdictions. The legal systems of certain countries, particularly certain developing countries, do not favor the enforcement of patents, trade secrets and other intellectual property protection, particularly those relating to biotechnology products, which could make it difficult for us to stop the infringement of our patents or marketing of competing products in violation of our proprietary rights generally. Proceedings to enforce our patent rights in foreign jurisdictions could result in substantial costs and divert our efforts and attention from other aspects of our business, could put our patents at risk of being invalidated or interpreted narrowly and our patent applications at risk of not issuing and could provoke third parties to assert claims against us. We may not prevail in any lawsuits that we initiate, and the damages or other remedies awarded, if any, may not be commercially meaningful. Accordingly, our efforts to enforce our intellectual property rights around the world may be inadequate to obtain a significant commercial advantage from the intellectual property that we develop or license.

Risks related to ownership of our common stock

The market price of our common stock may be highly volatile, and you could lose all or part of your investment.

The market price of our common stock is likely to be volatile. Our stock price could be subject to wide fluctuations in response to a variety of factors, including the following:

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In addition, companies trading in the stock market in general, and The Nasdaq Global Select Market in particular, have experienced extreme price and volume fluctuations that have often been unrelated or disproportionate to the operating performance of these companies. Broad market and industry factors may negatively affect the market price of our common stock, regardless of our actual operating performance.

Unstable market and economic conditions may have serious adverse consequences on our business, financial condition and stock price.

As widely reported, global credit and financial markets have experienced extreme volatility and disruptions in the past several years, including severely diminished liquidity and credit availability, declines in consumer confidence, declines in economic growth, increases in unemployment rates and uncertainty about economic stability. We cannot assure you that further deterioration in credit and financial markets and confidence in economic conditions will not occur. Our general business strategy may be adversely affected by any such economic downturn, volatile business environment or continued unpredictable and unstable market conditions. If the current equity and credit markets deteriorate, or do not improve, it may make any necessary debt or equity financing more difficult, more costly and more dilutive. Failure to secure any necessary financing in a timely manner and on favorable terms could have a material adverse effect on our growth strategy, financial performance and stock price and could require us to delay or abandon clinical development plans. In addition, there is a risk that one or more of our current service providers, manufacturers and other partners may not survive these difficult economic times, which could directly affect our ability to attain our operating goals on schedule and on budget.

We do not intend to pay dividends on our common stock so any returns will be limited to the value of our stock.

We have never declared or paid any cash dividends on our common stock. We currently anticipate that we will retain future earnings for the development, operation and expansion of our business and do not anticipate declaring or paying any cash dividends for the foreseeable future, including due to limitations that are currently imposed by our loan and security agreement. Any return to stockholders will therefore be limited to the appreciation of their stock.

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We are an emerging growth company, and we cannot be certain if the reduced reporting requirements applicable to emerging growth companies will make our common stock less attractive to investors.

We are an emerging growth company, as defined in the JOBS Act. For as long as we continue to be an emerging growth company, we may take advantage of exemptions from various reporting requirements that are applicable to other public companies that are not emerging growth companies, including not being required to comply with the auditor attestation requirements of Section 404 of the Sarbanes-Oxley Act of 2002, as amended, or the Sarbanes-Oxley Act, reduced disclosure obligations regarding executive compensation in our periodic reports and proxy statements and exemptions from the requirements of holding nonbinding advisory votes on executive compensation and stockholder approval of any golden parachute payments not previously approved. We could be an emerging growth company for up to five years following the year in which we completed our initial public offering, although circumstances could cause us to lose that status earlier. We will remain an emerging growth company until the earlier of (1) the last day of the fiscal year (a) following the fifth anniversary of the completion of our initial public offering (i.e. December 31, 2022), (b) in which we have total annual gross revenue of at least $1 billion or (c) in which we are deemed to be a large accelerated filer, which requires the market value of our common stock that is held by non-affiliates to exceed $700 million as of the prior June 30th, and (2) the date on which we have issued more than $1 billion in non-convertible debt during the prior three-year period.

Even after we no longer qualify as an emerging growth company, we may still qualify as a “smaller reporting company” which would allow us to take advantage of many of the same exemptions from disclosure requirements including not being required to comply with the auditor attestation requirements of Section 404 of the Sarbanes-Oxley Act and reduced disclosure obligations regarding executive compensation in our periodic reports and proxy statements. We cannot predict if investors will find our common stock less attractive because we may rely on these exemptions. If some investors find our common stock less attractive as a result, there may be a less active trading market for our common stock and our stock price may be more volatile.

Under the JOBS Act, emerging growth companies can also delay adopting new or revised accounting standards until such time as those standards apply to private companies. We have irrevocably elected not to avail ourselves of this exemption from new or revised accounting standards and, therefore, will be subject to the same new or revised accounting standards as other public companies that are not emerging growth companies. As a result, changes in rules of U.S. generally accepted accounting principles or their interpretation, the adoption of new guidance or the application of existing guidance to changes in our business could significantly affect our financial position and results of operations.

We will incur significant costs as a result of operating as a public company, and our management will be required to devote substantial time to compliance initiatives.

As a public company, we incur significant legal, accounting and other expenses that we did not incur as a private company. We are subject to the reporting requirements of the Securities Exchange Act of 1934, as amended, or the Exchange Act, which require, among other things, that we file with the SEC annual, quarterly and current reports with respect to our business and financial condition. In addition, the Sarbanes-Oxley Act, as well as rules subsequently adopted by the SEC and The NASDAQ Global Select Market to implement provisions of the Sarbanes-Oxley Act, impose significant requirements on public companies, including requiring establishment and maintenance of effective disclosure and financial controls and changes in corporate governance practices. Further, in July 2010, the Dodd-Frank Wall Street Reform and Consumer Protection Act, or the Dodd-Frank Act, was enacted. There are significant corporate governance and executive compensation related provisions in the Dodd-Frank Act that require the SEC to adopt additional rules and regulations in these areas such as “say on pay” and proxy access. Recent legislation permits emerging growth companies to implement many of these requirements over a longer period and up to five years from the pricing of our initial public offering. We intend to take advantage of this legislation but cannot guarantee that we will not be required to implement these requirements sooner than budgeted or planned and thereby incur unexpected expenses. Stockholder activism, the current political environment and the current level of government intervention and regulatory reform may lead to substantial new regulations and disclosure obligations, which may lead to additional compliance costs and impact the manner in which we operate our business in ways we cannot currently anticipate.

We expect the rules and regulations applicable to public companies to continue to result in substantial legal and financial compliance costs and to make some activities more time-consuming and costly. If these requirements divert the attention of our management and personnel from other business concerns, they could have a material adverse effect on our business, financial condition and results of operations. These costs could decrease our net income or increase our net loss, and may require us to reduce costs in other areas of our business or increase the prices of our products or services. For example, these rules and regulations could make it more difficult and more expensive for us to obtain director and officer liability insurance and we may be required to incur substantial costs to maintain the same or similar coverage. We cannot predict or estimate the amount or timing of additional costs we may incur to respond to these requirements. The impact of these requirements could also make it more difficult for us to attract and retain qualified persons to serve on our board of directors, our board committees or as executive officers.

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Sales of a substantial number of shares of our common stock in the public market could cause our stock price to fall.

If our existing stockholders sell, or indicate an intention to sell, substantial amounts of our common stock in the public market, the market price of our common stock could decline. We had 19,911,616 shares of common stock outstanding as of February 28, 2018. We are unable to predict the effect that sales may have on the prevailing market price of our common stock.

Sales of our common stock by current stockholders may make it more difficult for us to sell equity or equity-related securities in the future at a time and price that we deem reasonable or appropriate, and make it more difficult for you to sell shares of our common stock. In addition, as of December 31, 2017, 3,113,341 shares of common stock that are either subject to outstanding options, reserved for future issuance under our equity incentive plans or subject to outstanding warrants will become eligible for sale in the public market to the extent permitted by the provisions of various vesting schedules and Rule 144 and Rule 701 under the Securities Act. If these additional shares of common stock are sold, or if it is perceived that they will be sold, in the public market, the market price of our common stock could decline.

Future sales and issuances of our common stock or rights to purchase common stock, including pursuant to our equity incentive plans, could result in additional dilution of the percentage ownership of our stockholders and could cause our stock price to fall.

Additional capital will be needed in the future to continue our planned operations. To the extent we raise additional capital by issuing equity securities, our stockholders may experience substantial dilution. We may sell common stock, convertible securities or other equity securities in one or more transactions at prices and in a manner we determine from time to time. If we sell common stock, convertible securities or other equity securities in more than one transaction, investors may be materially diluted by subsequent sales. These sales may also result in material dilution to our existing stockholders, and new investors could gain rights superior to our existing stockholders.

Pursuant to our 2017 Equity Incentive Plan, or 2017 Plan, our management is authorized to grant stock options to our employees, directors and consultants.  The number of shares of our common stock reserved for issuance under our 2017 Plan will automatically increase on January 1 of each year through and including January 1, 2027, by 4% of the total number of shares of our capital stock outstanding on December 31 of the preceding calendar year, or a lesser number of shares determined by our board of directors.  Additionally, the number of shares of our common stock reserved for issuance under our 2017 Employee Stock Purchase Plan, or the ESPP, will automatically increase on January 1 of each year through and including January 1, 2027, by the lesser of 1% of the total number of shares of our capital stock outstanding on December 31 of the preceding calendar year, 300,000 shares or a lesser number of shares determined by our board of directors.  Unless our board of directors elects not to increase the number of shares available for future grant each year under the 2017 Plan and the ESPP, our stockholders may experience additional dilution, which could cause our stock price to fall.

We have broad discretion in the use of working capital and may not use it effectively.

Our management will have broad discretion in the application of working capital, and you will not have the opportunity as part of your investment decision to assess whether working capital is being used appropriately. Because of the number and variability of factors that will determine our use of our working capital, its ultimate use may vary substantially from its currently intended use. Our management might not apply our working capital in ways that ultimately increase the value of your investment. We intend to use our working capital to fund our Phase 3 clinical trial of Toca 511 & Toca FC in recurrent HGG, manufacturing scale-up and validation for Toca 511 & Toca FC, the other ongoing and planned clinical development activities for Toca 511 & Toca FC and for working capital and other general corporate purposes. The failure by our management to apply this working capital effectively could harm our business. Pending its use, we may invest our working capital in short-term, investment-grade, interest-bearing securities. These investments may not yield a favorable return to our stockholders. If we do not invest or apply our working capital in ways that enhance stockholder value, we may fail to achieve expected financial results, which could cause our stock price to decline.

The recently passed comprehensive tax reform bill could adversely affect our business and financial condition.

On December 22, 2017, President Trump signed into law new legislation that significantly revises the Internal Revenue Code of 1986, as amended, or IRC.  The newly enacted federal income tax law, among other things, contains significant changes to corporate taxation, including reduction of the corporate tax rate from a top marginal rate of 35% to a flat rate of 21%, limitation of the tax deduction for interest expense to 30% of adjusted earnings (except for certain small businesses), limitation of the deduction for net operating losses to 80% of current year taxable income and elimination of net operating loss carrybacks, one time taxation of offshore earnings at reduced rates regardless of whether they are repatriated, elimination of U.S. tax on foreign earnings (subject to certain important exceptions), immediate deductions for certain new investments instead of deductions for depreciation expense over time, and modifying or repealing many business deductions and credits (including reducing the business tax credit for certain clinical testing expenses incurred in the testing of certain drugs for rare diseases or conditions).  Notwithstanding the reduction in the corporate income tax rate, the overall impact of the new federal tax law is uncertain and our business and financial condition could be adversely affected.  In addition, it is unknown if and to what extent various states will conform to the newly enacted federal tax law.  The impact

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of this tax reform on holders of our common stock is likewise uncertain and could be adverse.  We urge our stockholders to consult with their legal and tax advisors with respect to this legislation and the potential tax consequences of investing in or holding our common stock.

Our ability to use our net operating loss carryforwards and certain other tax attributes may be limited.

As of December 31, 2017, we had federal and state net operating loss carryforwards of $137.8 million and $41.5 million, respectively. Our federal and state net operating loss carryforwards will begin to expire, if not utilized, beginning in 2028.  If these net operating loss carryforwards expire unused, they will be unavailable to offset future income and reduce future income tax liabilities. In addition, under the newly enacted federal income tax law, federal net operating losses incurred in 2018 and in future years may be carried forward indefinitely, but the deductibility of such federal net operating losses is limited.  It is uncertain if and to what extent various states will conform to the newly enacted federal tax law. Under Sections 382 and 383 of the IRC, if a corporation undergoes an “ownership change,” generally defined as a cumulative change in its equity ownership by “5-percent shareholders” of greater than 50 percentage points (by value) over a three-year period, the corporation’s ability to use its pre-change net operating loss carryforwards, or NOLs, and certain other pre-change tax attributes (such as research tax credits) to offset its post-change taxable income and taxes, as applicable, may be limited. We have completed an initial public offering and multiple rounds of financing since our inception which may have resulted in an ownership change or could result in an ownership change in the future. As of December 31, 2017, we have not completed a Section 382 and 383 analysis regarding any limitations on our NOLs and research and development credit carryforwards and such limitations could be significant. We may also experience ownership changes in the future as a result of subsequent shifts in our stock ownership. As a result, our ability to use our NOLs and research and development credit carryforwards to offset our U.S. federal taxable income and taxes, as applicable, may be subject to limitations, which could potentially result in increased future tax liability to us. In addition, at the state level, similar rules may apply and there may be periods during which the use of NOLs is suspended or otherwise limited, which could accelerate or permanently increase state taxes owed.

If securities or industry analysts do not publish research or publish inaccurate or unfavorable research about our business, our stock price and trading volume could decline.

The trading market for our common stock will depend in part on the research and reports that securities or industry analysts publish about us or our business. If one or more of the analysts who covers us downgrades our stock or publishes inaccurate or unfavorable research about our business, our stock price may decline. If one or more of these analysts ceases coverage of our company or fails to publish reports on us regularly, demand for our stock could decrease, which might cause our stock price and trading volume to decline.

Provisions in our amended and restated certificate of incorporation and amended and restated bylaws, as well as provisions of Delaware law, could make it more difficult for a third party to acquire us or increase the cost of acquiring us, even if doing so would benefit our stockholders or remove our current management.

Our amended and restated certificate of incorporation, amended and restated bylaws and Delaware law contain provisions that may have the effect of delaying or preventing a change in control of us or changes in our management. Our amended and restated certificate of incorporation and amended and restated bylaws, include provisions that:

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These provisions, alone or together, could delay or prevent hostile takeovers and changes in control or changes in our management.

In addition, because we are incorporated in Delaware, we are governed by the provisions of Section 203 of the Delaware General Corporation Law, which limits the ability of stockholders owning in excess of 15% of our outstanding voting stock to merge or combine with us.

Any provision of our amended and restated certificate of incorporation or amended and restated bylaws or Delaware law that has the effect of delaying or deterring a change in control could limit the opportunity for our stockholders to receive a premium for their shares of our common stock, and could also affect the price that some investors are willing to pay for our common stock.

Our amended and restated certificate of incorporation and amended and restated bylaws provide that the Court of Chancery of the State of Delaware is the sole and exclusive forum for substantially all disputes between us and our stockholders, which could limit our stockholders’ ability to obtain a favorable judicial forum for disputes with us or our directors, officers or employees.

Our amended and restated certificate of incorporation and amended and restated bylaws provide that the Court of Chancery of the State of Delaware is the sole and exclusive forum for (i) any derivative action or proceeding brought on our behalf; (ii) any action asserting a breach of fiduciary duty owed by any of our directors, officers or other employees to us or our stockholders; (iii) any action asserting a claim against us or any of our directors, officers or other employees arising pursuant to the Delaware General Corporation Law, our amended and restated certificate of incorporation or our amended and restated bylaws; or (iv) any action asserting a claim against us or any of our directors, officers or other employees that is governed by the internal affairs doctrine. The choice of forum provision may limit a stockholder’s ability to bring a claim in a judicial forum that it finds favorable for disputes with us or our directors, officers or other employees, which may discourage such lawsuits against us and our directors, officers and other employees. Alternatively, if a court were to find the choice of forum provision contained in our amended and restated certificate of incorporation and amended and restated bylaws to be inapplicable or unenforceable in an action, we may incur additional costs associated with resolving such action in other jurisdictions, which could adversely affect our business and financial condition.

Because we have an even number of members of our board of directors, deadlocks may occur in our board of directors’ decision-making process, which may delay or prevent critical decisions from being made.

Since we have an even number of directors, deadlocks may occur when such directors disagree on a particular decision or course of action. Our amended and restated certificate of incorporation and amended and restated bylaws do not contain any mechanisms for resolving potential deadlocks. While our directors are under a duty to act in the best interest of our company, any deadlocks may impede the further development of our business in that such deadlocks may delay or prevent critical decisions regarding our business.

Item 1B. Unresolved Staff Comments.

None.

Item 2. Properties.

As of December 31, 2017, we leased a total of approximately 19,000 square feet of laboratory and office space located at 3030 Bunker Hill Street Suite 230, San Diego, California. The lease was amended in March 2018 to provide for an extension of the lease term until June 30, 2018. Additionally, we will continue to lease approximately 2,000 square feet of our existing laboratory and office space through December 31, 2018.

On January 10, 2018, we entered into a new lease, or New Lease, totaling approximately 39,000 square feet of laboratory and office space located at 4242 Campus Point Court, San Diego, California, or the New Premises. The commencement date of the New Lease will be the earlier of (a) June 1, 2018, (b) substantial completion of tenant improvements, or (c) the date we begin conducting business operations in all or any portion of the New Premises. We expect to use the New Premises as our new principal executive

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offices and for general office, research and development, lab and pilot manufacturing uses. The term of the New Lease is eight years and we have one option to extend the New Lease for a period of five additional years.

We believe our existing and new facilities are adequate to meet our business requirements for the foreseeable future and are sufficient and suitable for the conduct of our business.

Item 3. Legal Proceedings.

None.

Item 4. Mine Safety Disclosures.

Not applicable.

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PART II

Item 5. Market for Registrant’s Common Equity, Related Stockholder Matters and Issuer Purchases of Equity Securities.

Market Information

Our common stock began trading on the NASDAQ Global Select Market under the symbol “TOCA” on April 13, 2017. Prior to that date, there was no public trading market for our common stock. The following table sets forth the high and low sales price per share of common stock as reported on the NASDAQ Global Select Market for the periods indicated:

Holders of Record

As of February 28, 2018, there were approximately 501 stockholders of record of our common stock. The actual number of stockholders is greater than this number of record holders and includes stockholders who are beneficial owners but whose shares are held in street name by brokers and other nominees. This number of holders of record also does not include stockholders whose shares may be held in trust or by other entities.

Dividend Policy

We have never declared or paid cash dividends on our capital stock. We currently intend to retain all available funds and any future earnings for use in the operation of our business and do not anticipate paying any dividends on our common stock in the foreseeable future. Any future determination to declare dividends will be made at the discretion of our board of directors and will depend on, among other factors, our financial condition, operating results, capital requirements, contractual restrictions, general business conditions and other factors that our board of directors may deem relevant. In addition, the terms of our loan and security agreement prohibit us from paying cash dividends.

Securities Authorized for Issuance Under Our Equity Compensation Plans

Information regarding securities authorized for issuance under our equity compensation plans is incorporated herein by reference to Item 12, “Security Ownership of Certain Beneficial Owners and Management and Related Stockholder Matters” of Part III of this Annual Report on Form 10-K.

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Stock Performance Graph

The following graph compares the cumulative total return to stockholders on our common stock relative to the cumulative total returns of the NASDAQ Composite Index and the NASDAQ Biotechnology Index. An investment of $100 (with reinvestment of all dividends) is assumed to have been made in our common stock and in each index on April 13, 2017, the date our common stock began trading on the NASDAQ Global Select Market, and its relative performance is tracked through December 31, 2017. The returns shown are based on historical results and are not intended to suggest future performance.

This performance graph shall not be deemed “soliciting material” or to be “filed” with the SEC for purposes of Section 18 of the Exchange Act, or otherwise subject to the liabilities under that Section, and shall not be deemed to be incorporated by reference into any filing of Tocagen Inc. under the Securities Act or the Exchange Act.

Recent Sales of Unregistered Securities

During the 12 months ended December 31, 2017, we issued and sold the following unregistered securities (excluding those previously disclosed in a Quarterly Report on Form 10-Q or in a Current Report on Form 8-K):

(1) In February 2017, we issued convertible promissory notes in an aggregate principal amount of $7.5 million to investors pursuant to a series of note purchase agreements. These notes and the notes that were issued during 2016, which aggregate into $11.1 million of principal plus accrued interest, converted into an aggregate of 1,109,176 shares of common stock in connection with our initial public offering.

(2) In March 2017, we granted stock options under our 2009 equity incentive plan, as amended, or the 2009 Plan, to purchase up to an aggregate of 103,934 shares of our common stock to certain of our employees at a weighted-average exercise price of $15.12 per share. From January 1, 2017 through April 12, 2017, 30,805 shares of common stock were issued upon the exercise of options granted to certain employees and consultants and the payment of $45,980 was made to us.

The offers, sales and issuances of the securities described in paragraph (1) were deemed to be exempt from registration under the Securities Act in reliance on Section 4(2) (or Regulation D promulgated thereunder) in that the issuance of securities to the accredited investors did not involve a public offering. The recipients of securities in each of these transactions acquired the securities for investment only and not with a view to or for sale in connection with any distribution thereof and appropriate legends were affixed to the securities issued in these transactions. Each of the recipients of securities in these transactions was an accredited investor under Rule 501 of Regulation D. No underwriters were involved in these transactions.

The offers, sales and issuances of the securities described in paragraph (2) were deemed to be exempt from registration under the Securities Act in reliance on either Rule 701 in that the transactions were under compensatory benefit plans and contracts relating to compensation as provided under Rule 701 or Section 4(2) in that the issuance of securities to the accredited investors did not involve a public offering. The recipients of such securities were our employees, directors or bona fide consultants and received the securities under our 2009 Plan.

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Use of Proceeds

On April 12, 2017, our Registration Statement on Form S-1 (file No. 333-216574) was declared effective by the SEC for our initial public offering of common stock. We issued 9,775,000 shares of common stock at an offering price of $10.00 per share for gross proceeds of $97.8 million.  After deducting underwriting discounts, commissions and offering costs incurred by us of $10.8 million, the net proceeds from the offering were $86.9 million.  The offering was completed on April 19, 2017. The joint bookrunning managers for the offering were Leerink Partners LLC, Evercore Group L.L.C. and Stifel, Nicolaus & Company, Incorporated. No offering costs were paid or are payable, directly or indirectly, to our directors or officers, to persons owning 10% or more of any class of our equity securities, or to any of our affiliates.

There has been no material change in the expected use of the net proceeds from our initial public offering as described in our final prospectus filed with the SEC on April 13, 2017. Through the date hereof, we have used $9.7 million of the net proceeds from the offering. Pending such uses, we plan to continue investing the unused proceeds from this offering in fixed, non-speculative income instruments.

Purchases of Equity Securities by the Issuer and Affiliated Purchasers

None.

Item 6. Selected Financial Data.

The following selected financial data should be read in conjunction with “Management’s Discussion and Analysis of Financial Condition and Results of Operations,” and our financial statements and the related notes thereto, each included elsewhere in this Annual Report on Form 10-K.

The statements of operations data for the years ended December 31, 2017, 2016 and 2015 and the balance sheet data as of December 31, 2017 and 2016 are derived from our audited financial statements included elsewhere in this Annual Report on Form 10-K. The selected balance sheet data as of December 31, 2015 is derived from audited financial statements that are not included in this Annual Report on Form 10-K. Our historical results are not necessarily indicative of the results that may be expected in any future period.

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Item 7. Management’s Discussion and Analysis of Financial Condition and Results of Operations.

You should read the following discussion and analysis of our financial condition and results of operations together with the section entitled “Selected Financial Data” and our financial statements and related notes appearing elsewhere in this Annual Report on Form 10-K. This discussion and analysis contains forward-looking statements based upon current expectations that involve risks and uncertainties. Our actual results may differ materially from those anticipated in these forward-looking statements as a result of various factors, including those discussed in the section entitled “Risk Factors” and in other parts of this Annual Report on Form 10-K. Please also see the section entitled “Special Note Regarding Forward-Looking Statements.”

Overview

We are a clinical-stage, cancer-selective gene therapy company focused on developing first-in-class, broadly-applicable product candidates designed to activate a patient’s immune system against their own cancer from within. Our cancer-selective gene therapy platform is built on retroviral replicating vectors, or RRVs, which are designed to selectively deliver therapeutic genes into the DNA of cancer cells. Our gene therapy approach is designed to fight cancer through immunotherapeutic mechanisms of action without the autoimmune toxicities commonly experienced with other immunotherapies.

We are developing our lead product candidate, Toca 511 (vocimagene amiretrorepvec) & Toca FC (flucytosine), initially for the treatment of recurrent high grade glioma, or HGG, a brain cancer with limited treatment options, low survival rates and, therefore, a significant unmet medical need. We are conducting a randomized, controlled Phase 3 clinical trial of Toca 511 & Toca FC in patients with recurrent HGG, which is designed to serve as a registrational trial. In February 2017, the U.S. Food and Drug Administration, or FDA, granted Toca 511 & Toca FC Breakthrough Therapy Designation for the treatment of patients with recurrent HGG and in June 2017 the European Medicines Agency, or EMA, granted Toca 511 Priority Medicines, or PRIME, Designation for the treatment of patients with glioma. Breakthrough Therapy Designation indicates that preliminary clinical evidence demonstrates the drug may have substantial improvement on one or more clinically significant endpoints over available therapy. PRIME Designation indicates that there is a potential to benefit patients with unmet medical needs based on early clinical data. We also have Fast Track Designation (which may lead to expedited regulatory review of new products that treat serious diseases or conditions and demonstrate the potential to address an unmet medical need) from the FDA for Toca 511 & Toca FC for the treatment of recurrent HGG and Orphan-Drug Designation (a designation for a product that treats a rare disease or condition and which, if the product receives the first FDA approval for that disease or condition, may result in a period of regulatory exclusivity, subject to some exceptions) for the treatment of HGG.  The Committee for Orphan Medicinal Products of the EMA has designated both flucytosine and vocimagene amiretrorepvec as orphan medicinal products indicated for the treatment of glioma. The EMA provides several benefits to drug developers for developing drugs for orphan diseases.

We do not have any products approved for sale and have not generated any revenue from product sales. We have funded our operations primarily through the private placement of our convertible preferred stock, from which we received net proceeds of $131.4 million and our initial public offering in April 2017, from which we received net proceeds of $86.9 million. We have also received $17.7 million in net proceeds from the issuance of our notes payable, $10.9 million from the issuance of our convertible promissory notes payable, $2.1 million from private and federal grants, and a $0.5 million up-front payment from our license and collaboration agreement with Siemens Healthcare Diagnostics Inc., or Siemens.

Since our inception in August 2007, we have devoted substantially all of our efforts to developing our gene therapy platform and our lead product candidate, Toca 511 & Toca FC. We have never been profitable and have incurred significant operating losses in each year since our inception. We had an accumulated deficit of $166.9 million as of December 31, 2017. Substantially all of our net losses resulted from costs incurred in connection with our research, preclinical, clinical, product, regulatory and business development activities, as well as raising capital and building our infrastructure.

We expect to continue to incur significant expenses and increasing net operating losses for at least the next several years. We expect our expenses will increase substantially in connection with our ongoing activities as we continue to develop and seek regulatory approval of our product candidates and operate as a public company. To fund further operations, we will need to raise additional capital.

Accordingly, we will seek to fund our operations through equity and/or debt financings. We may also consider new collaborations or selectively partnering our technology or programs. However, we may be unable to raise additional funds or enter into such other arrangements when needed on favorable terms or at all. In addition, subject to limited exceptions, our Loan Agreement (as defined below) also prohibits us from incurring indebtedness without the prior written consent of the lenders. Our failure to raise capital or enter into such other arrangements as and when needed would have a negative impact on our financial condition and our ability to develop our product candidates.

On April 19, 2017, we completed our initial public offering whereby we sold an aggregate of 9,775,000 shares of common stock, at $10.00 per share, resulting in net proceeds of $86.9 million after underwriting discounts, commissions and offering costs.

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In August 2017, we were awarded a $2.0 million grant payable over four years, by the FDA Office of Orphan Products Development to support our Phase 3 clinical trial of Toca 511 & Toca FC, or OOPD Grant. At December 31, 2017, we had received $0.5 million relating to the OOPD Grant.

Financial Operations Overview

Revenue

We currently have no products approved for sale, and have not generated any revenues from the sale of products. We have not submitted any product candidate for regulatory approval. Our revenue has been derived from our license and collaboration arrangement we entered into with Siemens in 2011, under which we received a nonrefundable, non-creditable, lump-sum, upfront license payment of $0.5 million for our sublicense to Siemens of certain diagnostic assay technology.

In the future, we may generate revenue from a combination of product sales and royalties in connection with our Siemens agreement and any future marketing and distribution arrangements and other collaborations, strategic alliances and license arrangements, or a combination of these approaches. However, we do not expect to receive additional revenues unless and until we receive regulatory approval for product candidates or potentially enter into collaboration agreements. We do not expect any of our current product candidates to be commercially available in major markets for at least the next few years. We expect that any revenue we generate will fluctuate from quarter to quarter and year to year as a result of the timing and amount of license fees, milestone and other payments, and the amount and timing of payments that we receive upon the sale of our products, to the extent any are successfully commercialized. If we fail to complete the development of our product candidates in a timely manner or obtain regulatory approval of them, our ability to generate future revenue, and our results of operations and financial position, would be materially adversely affected.

Research and Development Expenses

Research and development expenses consist primarily of salaries and related expenses for personnel, including stock-based compensation costs, preclinical costs, clinical trial costs, costs related to acquiring and manufacturing clinical trial materials, contract services, facilities costs, overhead costs and depreciation. These activities also include research and development related to our gene therapy platform development. All research and development costs are expensed as incurred.

We cannot determine with certainty the duration and completion costs of the current or future clinical trials of our product candidates, or if, when or to what extent we will generate revenues from the commercialization and sale of any of our product candidates that obtain regulatory approval. We may never succeed in achieving regulatory approval for any of our product candidates. The duration, costs and timing of clinical trials and development of our product candidates will depend on a variety of factors, including:

A change in the outcome of any of these variables with respect to the development of a product candidate could mean a significant change in the costs and timing associated with the development of that product candidate. For example, if the U.S. Food and Drug Administration, or FDA, or another regulatory authority were to require us to conduct clinical trials beyond those that we currently anticipate will be required for the completion of clinical development of a product candidate or if we experience significant delays in enrollment in any of our clinical trials, we could be required to expend significant additional financial resources and time on the completion of clinical development. In addition, the probability of success for each product candidate will depend on numerous factors, including competition, manufacturing capability and commercial viability. We will determine which programs to pursue and how much to fund each program in response to the scientific and clinical success of each product candidate, as well as an assessment of each product candidate’s commercial potential.

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The following table indicates our research and development expense by project for the years ended December 31, 2017, 2016 and 2015 (in thousands):

We expect our research and development expenses to increase for the foreseeable future as we scale up our clinical trial and manufacturing activities and seek regulatory approval of our product candidates.

General and Administrative Expenses

General and administrative expenses consist primarily of salaries and related expenses for personnel, including stock-based compensation costs and travel expenses for our employees in executive, operational, finance and business development functions. Other general and administrative expenses include facility-related costs, consulting fees for human resources and operations, capital raising and information technology, insurance, professional fees for accounting and legal services, expenses associated with obtaining and maintaining patents, and costs associated with being a public company.

We anticipate that our general and administrative expenses will increase in the future as we increase our headcount to support our expanding research and development and potential commercialization of our product candidates. We also anticipate continued increases in expenses related to audit, legal, regulatory and tax-related services associated with maintaining compliance with exchange listing and SEC requirements, director and officer insurance premiums and investor relations costs associated with being a public company. Additionally, if we believe a regulatory approval of our lead product candidate appears likely, we anticipate an increase in payroll and related expenses as a result of our preparation for commercial operations, especially as it relates to establishing a sales force and other expenses related to the sale and marketing of our product candidates.

Interest Income

Interest income consists primarily of interest income earned on cash, cash equivalents and marketable securities.

Interest Expense

Interest expense consists of stated interest and the amortization of related debt issuance costs incurred on the outstanding principal amount of our borrowings under our notes payable and convertible promissory notes payable.

Change in Fair Value of Preferred Stock Warrants

Warrants for shares of preferred stock with conversion features are accounted for as liabilities in the accompanying balance sheets at their fair value on the date of issuance. The warrant liabilities are revalued at each balance sheet date until such instruments are exercised or expire, with changes in the fair value between reporting periods recorded as change in fair value of preferred stock warrants in the statement of operations. All preferred stock warrant liabilities were reclassified to equity in connection with our initial public offering.

Critical Accounting Policies and Significant Judgments and Estimates

Our management’s discussion and analysis of our financial condition and results of operations is based on our financial statements which we have prepared in accordance with generally accepted accounting principles in the United States, or GAAP. The preparation of these financial statements requires us to make estimates and assumptions that affect the reported amounts of assets and liabilities and disclosure of contingent assets and liabilities at the date of the financial statements, and the reported amounts of revenue and expenses during the reporting period. Actual results could differ from those estimates.

While our significant accounting policies are described in more detail in the Note 2 to our financial statements appearing at the end of this Annual Report on Form 10-K, we believe the following accounting policies to be most critical for fully understanding and evaluating our financial condition and results of operations.

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Accrued Research and Development Expenses

As part of the process of preparing our financial statements, we are required to estimate our accrued research and development expenses. This process involves reviewing open contracts and purchase orders, communicating with our personnel to identify services that have been performed on our behalf and estimating the level of service performed and the associated cost incurred for the service when we have not yet been invoiced or otherwise notified of the actual cost. The majority of our service providers invoice us monthly in arrears for services performed or when contractual milestones are met. We make estimates of our accrued expenses as of each balance sheet date in our financial statements based on facts and circumstances known to us at that time. Examples of estimated accrued research and development expenses include fees paid to: investigative sites and contract research organizations in connection with clinical trials; service providers in connection with preclinical development activities; and service providers related to product manufacturing.

We base our expenses related to clinical trials on our estimates of the services received and efforts expended pursuant to our contract arrangements. The financial terms of these agreements are subject to negotiation, vary from contract to contract and may result in uneven payment flows. There may be instances in which payments made to our service providers will exceed the level of services provided and result in a prepayment of the clinical expense. Payments under some of these contracts depend on factors such as the successful enrollment of patients, site initiation and the completion of clinical milestones. In accruing service fees, we estimate the time period over which services will be performed and the level of effort to be expended in each period. If the actual timing of the performance of services or the level of effort varies from our estimate, we adjust the accrual or prepaid expense balance accordingly.

Although we do not expect our estimates to be materially different from amounts actually incurred, if our estimates of the status and timing of services performed differ from the actual status and timing of services performed, we may report amounts that are too high or too low in any particular period. To date, there have been no material differences from our estimates to the amount actually incurred. However, due to the nature of estimates, we cannot assure you that we will not make changes to our estimates in the future as we become aware of additional information about the status or conduct of our clinical trials and other research activities.

Stock-Based Compensation

Stock-based compensation expense represents the cost of the grant date fair value of stock awards, including stock options, and stock purchase rights granted to employees. For awards with time-based vesting provisions, we estimate the fair value of stock options on the date of grant using the Black-Scholes option pricing model and recognize the expense over the requisite service period of the awards which is generally the vesting period, on a straight-line basis. The Black-Scholes option pricing model requires the input of highly subjective assumptions, including the risk-free interest rate, the expected volatility, the expected term of the option, the expected dividend yield of our common stock and the estimated fair value of our common stock. For awards with performance-based vesting provisions, we estimate the fair value of stock option grants on the date of grant, or the date when all of the terms of the grant have been agreed to, if later, and recognize the expense based on the probability of the occurrence of the individual milestones at each reporting period. The expense is recognized over the implicit service period that commences once management believes the performance criteria are probable of being met. Prior to January 1, 2016, we estimated forfeitures at the time of grant with stock-based compensation expense based on awards that were ultimately expected to vest. Beginning January 1, 2016, upon adoption of new accounting guidance, we account for forfeitures when they occur, and reverse any compensation cost previously recognized for awards for which the requisite service has not been completed, in the period that the award is forfeited.

We calculate the estimated fair value of each non-employee stock option award at the date of grant using Black-Scholes option pricing model with the assumptions generally consistent with those used for employee stock options, with the exception of expected term, which is over the contractual life. These options are subject to periodic revaluation over their vesting terms.

Income Taxes

We account for income taxes under the asset and liability method, which requires the recognition of deferred tax assets and liabilities for the expected future tax consequences that have been included in the financial statements. Under this method, deferred tax assets and liabilities are determined on the basis of the differences between the financial statements and tax basis of assets and liabilities using enacted tax rates in effect for the year in which the differences are expected to reverse. We record a full valuation allowance against net deferred tax assets unless, based upon the available evidence, it is more likely than not that the deferred tax assets will be realized.

We record uncertain tax positions on the basis of a two-step process whereby (i) management determines whether it is more likely than not that the tax positions will be sustained on the basis of the technical merits of the position and (ii) for those tax positions that meet the more likely-than-not recognition threshold, management recognizes the largest amount of tax benefit that is more than 50 percent likely to be realized upon ultimate settlement with the related tax authority. We will recognize interest and penalties in income tax expense if and when incurred.

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Emerging Growth Company Status

The JOBS Act permits an “emerging growth company” such as us to take advantage of an extended transition period to comply with new or revised accounting standards applicable to public companies. Thus, an emerging growth company can delay the adoption of certain accounting standards until those standards would otherwise apply to private companies. We have irrevocably elected not to avail ourselves of this extended transition period and, as a result, we will adopt new or revised accounting standards on the relevant dates on which adoption of such standards is required for other public companies.

Recent Accounting Pronouncements

We have reviewed all recently issued standards and have determined that other than as disclosed in Note 2 to our financial statements included in this Annual Report on Form 10-K, such standards will not have a material impact on our financial statements or do not otherwise apply to our operations.

Results of Operations

Comparison of the Years Ended December 31, 2017 and 2016

The following table summarizes our results of operations for the years ended December 31, 2017 and 2016 (in thousands):

License revenue.    License revenue was $41,000 for the year ended December 31, 2017 as compared to $49,000 for the year ended December 31, 2016, a decrease of $8,000.

Research and development expenses.    Research and development expenses were $29.1 million for the year ended December 31, 2017, as compared to $27.2 million for the year ended December 31, 2016. The increase of $1.9 million, or 7%, was primarily due to increased personnel costs to support our ongoing Phase 3 clinical trial. We anticipate our research and development expenses will increase in future years.

General and administrative expenses.    General and administrative expenses were $8.6 million for the year ended December 31, 2017, as compared to $4.5 million for the year ended December 31, 2016. The increase of $4.0 million, or 89%, was primarily due to higher costs to support increased operations activity as we conduct our Phase 3 clinical trial and costs associated with being a public company. Stock-based compensation expense, which represents 47% of the increase, is due primarily to stock options granted to members of our board of directors, our chief executive officer and other employees.

Interest income.    Interest income was $0.6 million for the year ended December 31, 2017, as compared to $0.2 million for the year ended December 31, 2016. The increase of $0.4 was primarily due to our higher average cash balances earning interest at higher rates during 2017 compared to 2016.

Interest Expense.    Interest expense was $1.9 million for the year ended December 31, 2017 and represents $1.1 million in stated interest, $0.6 million in amortization of related debt issuance costs incurred on the outstanding principal amount of our borrowings under our notes payable and $0.2 million in interest on our convertible promissory notes payable. Interest expense was $2.1 million for the year ended December 31, 2016 and represents $1.5 million in stated interest and $0.6 million in amortization of related debt issuance costs incurred on the outstanding principal amount of our borrowings under our notes payable, and $24,000 in interest on our convertible promissory notes payable issued in November and December 2016.

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Comparison of the Years Ended December 31, 2016 and 2015

The following table summarizes our results of operations for the years ended December 31, 2016 and 2015 (in thousands):

License revenue.    License revenue was $49,000 for the year ended December 31, 2016 as compared to $51,000 for the year ended December 31, 2015, a decrease of $2,000.

Research and development expenses.    Research and development expenses were $27.2 million for the year ended December 31, 2016, as compared to $19.2 million for the year ended December 31, 2015. The increase of $8.0 million, or 42%, was primarily due to continued increases in clinical and manufacturing costs incurred to support our Phase 2/3 clinical trial, as well as pre-initiation costs for our Phase 1b clinical trial in solid tumors during 2016.

General and administrative expenses.    General and administrative expenses were $4.5 million for the year ended December 31, 2016, as compared to $3.8 million for the year ended December 31, 2015. The increase of $0.7 million, or 18%, was primarily due to increased costs for supporting the higher level of company operations as we conducted our Phase 2/3 clinical trial.

Interest income.    Interest income was $0.2 million for the year ended December 31, 2016, as compared to $0.1 million for the year ended December 31, 2015. The increase of $89,000 was primarily due to our average cash balances earning interest at higher rates during 2016 compared to 2015.

Interest Expense.    Interest expense was $2.1 million for the year ended December 31, 2016 and represents $1.5 million in stated interest and $0.6 million in amortization of related debt issuance costs incurred on the outstanding principal amount of our borrowings under our notes payable, and $24,000 in interest on our convertible promissory notes payable issued in November and December 2016. Interest expense was $0.3 million for the year ended December 31, 2015 and represents $0.2 million in stated interest and $0.1 million in amortization of related debt issuance costs incurred on the outstanding principal amount of our borrowings under our notes payable issued in October 2015.

Liquidity and Capital Resources

We have incurred significant losses and cumulative negative cash flows from operations since our inception. As of December 31, 2017, we had an accumulated deficit of $166.9 million and we anticipate that we will continue to incur losses for at least the next several years. We expect that our research and development and general and administrative expenses will continue to increase and, as a result, we will need additional capital to fund our operations, which we may raise through equity and/or debt financings. We may also consider new collaborations or selectively partnering our technology or programs.

Since inception through December 31, 2017, we have funded our operations primarily through the private placement of our convertible preferred stock from which we received net proceeds of $131.4 million and our initial public offering from which we received net proceeds of $86.9 million. In addition, we have also received $17.7 million in net proceeds from the issuance of our notes payable, $10.9 million from the issuance of our convertible promissory notes payable, $2.1 million from private grant funding and federal grants, and a $0.5 million up-front payment under the Siemens license and collaboration agreement.

The loans under our loan and security agreement, or the Loan Agreement, with two lenders, dated October 30, 2015, are secured by substantially all of our assets other than our intellectual property (except rights to payment from the sale, licensing of disposition of such intellectual property). We borrowed $18.0 million upon execution of the Loan Agreement. Balances under the Loan Agreement accrue interest at the prime rate plus 4.5%, subject to a floor of 7.75%.  The interest rate as of December 31, 2017 was 8.75%. The loans under the Loan Agreement mature in May 2019 and are due in monthly payments of principal and interest. The Loan Agreement contains customary conditions of borrowing, events of default and covenants, including covenants that restrict our ability to dispose of assets, merge with or acquire other entities, incur indebtedness and make distributions to holders of our capital stock. Should an event of default occur, including the occurrence of a material adverse change, we could be liable for immediate repayment of all obligations under the Loan Agreement.

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As of December 31, 2017, we had $88.7 million in cash, cash equivalents and marketable securities.  Our available cash and marketable securities are invested in accordance with our investment policy, primarily with a view to preserve principal and maintain liquidity. Currently, our funds are held in FDIC insured cash accounts, certificates of deposits, money market funds and investment-grade fixed income securities.

Cash Flows

The following table sets forth the primary sources and uses of cash for each of the periods set forth below (in thousands):

Operating Activities.     Net cash used in operating activities was $31.1 million for the year ended December 31, 2017, and consisted primarily of a net loss of $38.9 million adjusted for a net increase in cash from operating assets and liabilities of $2.5 million, noncash stock-based compensation expense of $4.5 million, depreciation expense of $0.3 million and noncash interest expense of $0.6 million. The $2.5 million net increase in cash from operating assets and liabilities is due primarily to a $3.2 million increase in our accounts payable and accrued liabilities resulting mainly from increased accrued payroll and related liabilities and continued increases in clinical costs incurred to support our clinical trials, primarily offset by a $0.7 million increase in prepaid expenses related to our manufacturing costs.

Net cash used in operating activities was $29.5 million for the year ended December 31, 2016, and consisted primarily of a net loss of $33.5 million adjusted for a net increase in cash from operating assets and liabilities of $1.8 million, noncash stock-based compensation expense of $1.3 million, depreciation expense of $0.3 million and noncash interest expense of $0.6 million. The $1.8 million net increase in cash from operating assets and liabilities is due primarily to a $2.1 million increase in our accounts payable and accrued liabilities resulting mainly from continued increases in clinical and manufacturing costs incurred to support our clinical trials and increased accrued payroll and related liabilities, primarily offset by a $0.2 million increase in prepaid expenses related to our clinical trial costs.

Net cash used in operating activities was $21.0 million for the year ended December 31, 2015, and consisted primarily of a net loss of $23.1 million adjusted for a net increase in cash from operating assets and liabilities of $0.7 million, noncash stock-based compensation expense of $1.1 million, depreciation expense of $0.2 million, noncash interest expense of $0.1 million and a noncash reduction in the fair value of our preferred stock warrants of $0.1 million. The $0.7 million net increase in cash from operating assets and liabilities is due primarily to a $1.9 million increase in our accounts payable and accrued liabilities resulting mainly from continued increases in clinical and manufacturing costs incurred to support our clinical trials and increased accrued payroll and related liabilities, primarily offset by a $1.1 million increase in prepaid expenses related to our clinical trial costs.

Investing Activities.     Net cash used in investing activities for the year ended December 31, 2017 was $27.7 million and consisted of purchases of marketable securities of $70.8 million and the purchase of property and equipment of $0.7 million offset primarily by proceeds from the maturity of marketable securities of $43.7 million.

Net cash provided by investing activities for the year ended December 31, 2016 was $24.6 million and consisted of proceeds from the maturity of marketable securities of $48.1 million, primarily offset by purchases of marketable securities of $23.0 million and the purchase of property and equipment of $0.5 million.

Net cash used in investing activities for the year ended December 31, 2015 was $24.9 million and consisted primarily of purchases of marketable securities of $59.9 million and purchases of property and equipment of $0.2 million, primarily offset by proceeds from the maturity of marketable securities of $35.2 million.

Financing activities.    Net cash provided by financing activities for the year ended December 31, 2017 was $89.3 million and consisted primarily of net proceeds from our initial public offering of common stock of $88.6 million and $7.3 million from the issuance of convertible promissory notes payable and convertible promissory note subscriptions which were offset by $7.2 million in principal payments on our notes payable.

Net cash provided by financing activities for the year ended December 31, 2016 was $2.3 million and consisted primarily of net proceeds of $3.5 million from the issuance of convertible promissory notes payable and convertible promissory note subscriptions which was offset by $0.6 million in principal payments on our notes payable and $0.6 million in cash paid for deferred equity issuance costs.

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Net cash provided by financing activities for the year ended December 31, 2015 was $49.9 million and consisted primarily of (i) the sale of 6,376,037 shares of our Series H convertible preferred stock for net proceeds of $33.4 million, of which $0.4 million was received in late December 2014 for subscription agreements that did not close until 2015, (ii) $17.7 million in net proceeds from the issuance of our notes payable in October 2015, and (iii) $0.2 million from the issuance of common stock in connection with the exercise of stock options. These proceeds were primarily offset by $1.0 million in cash paid for deferred equity issuance costs.

Funding Requirements

Our primary uses of capital are, and we expect will continue to be, compensation and related expenses for personnel, third-party clinical research and development services, laboratory expenses, regulatory expenses, marketing, and general and administrative expenses. Based on our research and development plans and our timing expectations related to the progress of our programs, we expect that our existing cash, cash equivalents and marketable securities as of December 31, 2017 will enable us to fund our operations for at least the next 12 months. We have based this estimate on assumptions that may prove to be wrong, and we could use our available capital resources sooner that we currently expect. Furthermore, our operating plan may change and we may need additional funds sooner than planned.

The successful development of any product candidate is highly uncertain. As such, at this time, we cannot reasonably estimate or know the nature, timing and costs of the efforts that will be necessary to complete the development of Toca 511 & Toca FC or our other current and future product candidates. We are also unable to predict when, if ever, material net cash inflows will commence from the sale of product candidates. This is due to the numerous risks and uncertainties associated with developing immunotherapies, including the uncertainty of:

A change in the outcome of any of these variables with respect to the development of any of our product candidates would significantly change the costs and timing associated with the development of that product candidate.

Until we can generate a sufficient amount of revenue from our products, if ever, we expect to finance future cash needs through equity and/or debt financings. We may also consider new collaborations or selectively partnering our technology or programs.  We do not have any committed external source of funds. Additional capital may not be available on reasonable terms, if at all. Subject to limited exceptions, our Loan Agreement also prohibits us from incurring indebtedness without the prior written consent of the lenders. If we are unable to raise additional capital in sufficient amounts or on terms acceptable to us, we may have to significantly delay, scale back or discontinue the development or commercialization of one or more of our product candidates. If we raise additional funds through the issuance of additional equity or debt securities, it could result in dilution to our existing stockholders and increased fixed payment obligations, and these securities may have rights senior to those of our common stock. If we incur indebtedness, we could become subject to covenants that would restrict our operations and potentially impair our competitiveness, such as limitations on our ability to incur additional debt, limitations on our ability to acquire, sell or license intellectual property rights and other operating restrictions that could adversely impact our ability to conduct our business. Any of these events could significantly harm our business, financial condition and prospects.

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Off-Balance Sheet Arrangements

We did not have during the periods presented, and we do not currently have, any off-balance sheet arrangements, as defined in the rules and regulations of the SEC.

Contractual Obligations and Commitments

The following table summarizes our contractual obligations and commitments as of December 31, 2017 that will affect our future liquidity (in thousands):

On January 10, 2018, we entered into a new lease, or the New Lease, totaling approximately 39,000 square feet of laboratory and office space located at 4242 Campus Point Court, San Diego, California, or the New Premises. The commencement date of the New Lease will be the earlier of (a) June 1, 2018, (b) substantial completion of tenant improvements, or (c) the date we begin conducting business operations in all or any portion of the New Premises. We expect to use the New Premises as our new principal executive offices and for general office, research and development, lab and pilot manufacturing uses. The term of the New Lease is eight years and we have one option to extend the New Lease for a period of five additional years.

Annual base rental lease obligations related to the New Lease are as follows (in thousands):

The New Lease provides for an abatement of a portion of the lease payments for the first nine months of the lease term as well as a tenant improvement allowance of approximately $1.2 million. We expect to pay for leasehold improvements in excess of the tenant improvement allowance. In the event of a default of certain of our obligations under the New Lease, the landlord would have the right to terminate the New Lease.

Our existing laboratory and office lease at 3030 Bunker Hill Street Suite 230 was amended in March 2018 to provide for an extension of the lease term until June 30, 2018. Additionally, we will continue to lease approximately 2,000 square feet of our existing laboratory and office space through December 31, 2018. Our annual base rental lease obligation in 2018 under our existing building lease is approximately $0.2 million.

We also have obligations under license, collaboration and various grant agreements to make future payments to third parties that become due and payable on the achievement of certain commercial milestones. We have not included these commitments on our balance sheet or in the table above because the achievement and timing of these events is not fixed and determinable. These commitments are listed as follows:

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We enter into contracts in the ordinary course of business with clinical sites for the conduct of clinical trials, service providers for product manufacture and preclinical research studies, professional consultants for expert advice and other vendors for laboratory and research supplies and services. These contracts generally provide for termination on notice, and therefore are cancelable contracts and not included in the table of contractual obligations and commitments. In addition, these contracts have indemnification clause whereby we indemnify, defend, hold harmless and agree to reimburse the indemnified party for losses suffered or incurred by third party claims arising out of the indemnified party’s performance of service. The term of these indemnification clauses is perpetual any time after execution of the agreement. The maximum potential amount of future payments we could be required to make under these indemnification clauses is unlimited. We have not incurred costs to defend lawsuits or settle claims related to these indemnification clauses.

Item 7A. Quantitative and Qualitative Disclosures About Market Risk.

The primary objective of our investment activities is to preserve our capital to fund our operations. We also seek to maximize income from our investments without assuming significant risk. To achieve our objectives, we maintain a portfolio of cash equivalents and investments in securities of high credit quality. As of December 31, 2017, we had cash, cash equivalents and marketable securities of $88.7 million consisting of cash and investments in certificates of deposit, money market funds, and investment-grade fixed income securities. A significant portion of our investments may be subject to interest rate risk and could fall in value if market interest rates increase. However, because our investments are primarily short-term in duration, we believe that our exposure to interest rate risk is not significant and a 1% movement in market interest rates would not have a significant impact on the total value of our portfolio. We actively monitor changes in interest rates.

Item 8. Financial Statements and Supplementary Data.

The financial statements and supplementary data required by this item are included after the Signatures page of this Annual Report on Form 10-K beginning on page F-1.

Item 9. Changes in and Disagreements With Accountants on Accounting and Financial Disclosure.

None.

Item 9A. Controls and Procedures.

Evaluation of Disclosure Controls and Procedures

As required by Rules 13a-15(b) and 15d-15(b) of the Exchange Act, our management with the participation of our Chief Executive Officer and our Chief Financial Officer, evaluated the effectiveness of our disclosure controls and procedures as of December 31, 2017. The term “disclosure controls and procedures” as defined in Rules 13a-15(e) and 15d-15(e) under the Exchange Act, means controls and other procedures of a company that are designed to ensure that information required to be disclosed by a company in the reports that it files or submits under the Exchange Act is recorded, processed, summarized and reported, within the time periods specified in the SEC’s rules and forms. Disclosure controls and procedures include, without limitation, controls and procedures designed to ensure that information required to be disclosed by a company in the reports that it files or submits under the Exchange Act is accumulated and communicated to the company’s management, including its principal executive and principal financial officer, as appropriate to allow timely decisions regarding required disclosure. Management recognizes that any controls and procedures, no matter how well designed and operated, can provide only reasonable assurance of achieving their objectives, and management necessarily applies its judgment in evaluating the cost-benefit relationship of possible controls and procedures. Based on the evaluation of our disclosure controls and procedures as of December 31, 2017, our Chief Executive Officer and our Chief Financial Officer concluded that, as of such date, our disclosure controls and procedures were effective at the reasonable assurance level.

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Management’s Report on Internal Control over Financial Reporting

This Annual Report on Form 10-K does not include a report of management’s assessment regarding internal control over financial reporting or an attestation report of our registered public accounting firm due to a transition period established by rules of the SEC for newly public companies.

Changes in Internal Control over Financial Reporting

There were no changes in our internal control over financial reporting that occurred during the quarter ended December 31, 2017 that have materially affected, or are reasonably likely to materially affect, our internal control over financial reporting.

Inherent Limitations of Disclosure Controls and Internal Control over Financial Reporting

Because of their inherent limitations, our disclosure controls and procedures and our internal control over financial reporting may not prevent material errors or fraud. A control system, no matter how well conceived and operated, can provide only reasonable, not absolute, assurance that the objectives of the control system are met. The effectiveness of our disclosure controls and procedures and our internal control over financial reporting is subject to risks, including that the controls may become inadequate because of changes in conditions or that the degree of compliance with our policies or procedures may deteriorate.

Item 9B. Other Information.

None.

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PART III

Item 10. Directors, Executive Officers and Corporate Governance.

The information required by this item and not set forth below will be contained in our definitive proxy statement to be filed with the Securities and Exchange Commission in connection with our 2018 Annual Meeting of Stockholders, or the Proxy Statement, which is expected to be filed not later than 120 days after the end of our fiscal year ended December 31, 2017, and is incorporated herein by reference.

We have adopted a written Code of Business Conduct and Ethics, or Ethics Code, that applies to all officers, directors and employees, including our principal executive officer, principal financial officer, principal accounting officer or controller, or persons performing similar functions. The Ethics Code is available on our website at www.tocagen.com. If we make any substantive amendments to the Ethics Code or grant any waiver from a provision of the Ethics Code to any executive officer or director, we will promptly disclose the nature of the amendment or waiver on our website or in a current report on Form 8-K.

Item 11. Executive Compensation.

The information required by this item will be set forth in the Proxy Statement and is incorporated herein by reference.

Item 12. Security Ownership of Certain Beneficial Owners and Management and Related Stockholder Matters.

The information required by this item will be set forth in the Proxy Statement and is incorporated herein by reference.

Item 13. Certain Relationships and Related Transactions, and Director Independence.

The information required by this item will be set forth in the Proxy Statement and is incorporated herein by reference.

Item 14. Principal Accounting Fees and Services.

The information required by this item will be set forth in the Proxy Statement and is incorporated herein by reference.

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PART IV

Item 15. Exhibits, Financial Statement Schedules.

The Financial Statements of Tocagen Inc. and Report of Independent Registered Public Accounting Firm are included after the Signatures page of this Annual Report on Form 10-K beginning on page F-1.

These schedules have been omitted because the required information is included in the financial statements or notes thereto or because they are not applicable or not required.

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Exhibit Index

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