AMARIN CORP PLC\UK - Annual Report: 2012 (Form 10-K)

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UNITED STATES

SECURITIES AND EXCHANGE COMMISSION

Washington, D.C. 20549

Form 10-K

For the fiscal year ended December 31, 2012

OR

For the transition period from             to            

Commission File No. 0-21392

Amarin Corporation plc

(Exact name of registrant as specified in its charter)

2 Pembroke House

Upper Pembroke Street 28-32, Dublin 2, Ireland

(Address of principal executive offices)

+353 (0) 1 6699 020

(Registrant’s telephone number, including area code)

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

Securities registered pursuant to Section 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  þ    NO  ¨

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

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  þ    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  þ    NO  ¨

Indicate by check mark if disclosure of delinquent filers pursuant to Item 405 of Regulation S-K (§229.405 of this chapter) 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, or a smaller reporting company. See the definitions of “large accelerated filer,” “accelerated filer” and “smaller reporting company” in Rule 12b-2 of the Exchange Act. (Check one):

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

The aggregate market value of the voting and non-voting common equity held by non-affiliates of the registrant as of June 30, 2012 was approximately $1.92 billion, based upon the closing price on the NASDAQ Capital Market reported for such date.

149,991,187 shares held as American Depository Shares (ADS), each representing one Ordinary Share, 50 pence par value per share, and 380,694 Ordinary Shares, were outstanding as of February 20, 2013.

DOCUMENTS INCORPORATED BY REFERENCE

Certain information required to be disclosed in Part III of this report is incorporated by reference from the registrant’s definitive proxy statement to be filed not later than 120 days after the end of the fiscal year covered by this report.

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PART I

SPECIAL NOTE REGARDING

FORWARD-LOOKING STATEMENTS AND INDUSTRY DATA

This Annual Report on Form 10-K contains forward-looking statements. All statements other than statements of historical fact contained in this Annual Report on Form 10-K are forward-looking statements, including statements regarding the progress and timing of our clinical programs, regulatory filings and commercialization activities, and the potential clinical benefits, safety and market potential of our product candidates, as well as more general statements regarding our expectations for future financial and operational performance, regulatory environment, and market trends. In some cases, you can identify forward-looking statements by terminology such as “may,” “would,” “should,” “could,” “expects,” “aims,” “plans,” “anticipates,” “believes,” “estimates,” “predicts,” “projects,” “potential,” or “continue” the negative of these terms; or other comparable terminology. These statements include but are not limited to statements regarding the commercial success of Vascepa in its first approved indication, the MARINE indication, the potential for, and timing of, approval of the Vascepa Supplemental New Drug Application, or sNDA, by the United States Food and Drug Administration, or FDA, in its potential second indication, the ANCHOR indication; the safety and efficacy of our product candidates; the scope of our intellectual property protection and the likelihood of securing additional patent protection and regulatory exclusivity; estimates of the potential markets for our product candidates; the likelihood of qualifying additional third party manufacturing suppliers and estimates of the capacity of manufacturing and other facilities to support our products; our operating and growth strategies; our industry; our projected cash needs, liquidity and capital resources; and our expected future revenues, operations and expenditures.

Forward-looking statements are only current predictions and are subject to known and unknown risks, uncertainties, and other factors that may cause our or our industry’s actual results, levels of activity, performance, or achievements to be materially different from those anticipated by such statements. These factors include, among other things, those listed under “Risk Factors” in Item 1A of Part I of this Annual Report on Form 10-K and elsewhere in this Annual Report on Form 10-K. These and other factors could cause results to differ materially from those expressed in these forward-looking statements.

Although we believe that the expectations reflected in the forward-looking statements contained in this Annual Report on Form 10-K are reasonable, we cannot guarantee future results, performance, or achievements. Except as required by law, we are under no duty to update or revise any of such forward-looking statements, whether as a result of new information, future events or otherwise, after the date of this Annual Report on Form 10-K.

Unless otherwise indicated, information contained in this Annual Report on Form 10-K concerning our product candidates, the number of patients that may benefit from these product candidates and the potential commercial opportunity for our product candidates, is based on information from independent industry analysts and third-party sources (including industry publications, surveys, and forecasts), our internal research, and management estimates. Management estimates are derived from publicly available information released by independent industry analysts and third-party sources, as well as data from our internal research, and based on assumptions made by us based on such data and our knowledge of such industry, which we believe to be reasonable. None of the sources cited in this Annual Report on Form 10-K has consented to the inclusion of any data from its reports, nor have we sought their consent. Our internal research has not been verified by any independent source, and we have not independently verified any third-party information. While we believe that such information included in this Annual Report on Form 10-K is generally reliable, such information is inherently imprecise. In addition, projections, assumptions, and estimates of our future performance are necessarily subject to a high degree of uncertainty and risk due to a variety of factors, including those described in “Risk Factors” in Item 1A of Part I of this Annual Report on Form 10-K and elsewhere in this Annual Report on Form 10-K. These and other factors could cause results to differ materially from those expressed in the estimates made by the independent parties and by us.

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References in this report to “Amarin,” the “Company,” “we,” “our” and “us” refer to Amarin Corporation plc and its subsidiaries, on a consolidated basis, unless otherwise indicated.

This Annual Report on Form 10-K includes the registered and unregistered trademarks and service marks of other parties.

Amarin Corporation plc (formerly Ethical Holdings plc) is a public limited company incorporated under the laws of England and Wales. Amarin Corporation plc was originally incorporated in England as a private limited company on March 1, 1989 under the Companies Act 1985, and re-registered in England as a public limited company on March 19, 1993.

Our registered office is located at One New Change, London EC4M 9AF, England. Our principal offices are located at 2 Pembroke House, Upper Pembroke Street 28-32, Dublin 2 Ireland. Our primary office in the United States is located at 1430 Route 206, Bedminster, NJ 07921, USA. Our telephone number at that location is (908) 719-1315.

For purposes of this Annual Report on Form 10-K, our ordinary shares may also be referred to as “common shares” or “common stock.”

Overview

We are a biopharmaceutical company focused on the commercialization and development of therapeutics to improve cardiovascular health. On July 26, 2012, we received approval from the U.S. Food and Drug Administration, or FDA, to market and sell our lead product Vascepa^® (icosapent ethyl) capsules (formerly known as AMR101) as an adjunct to diet to reduce triglyceride, or TG, levels in adult patients with severe (TG ³500mg/dL) hypertriglyceridemia, which we sometimes refer to as the MARINE indication. Vascepa became commercially available in the United States by prescription in January 2013, when we commenced sales and shipments to our network of U.S.-based wholesalers. On January 28, 2013, we commenced our full commercial launch of Vascepa in the United States for the MARINE indication.

We are also developing Vascepa for the treatment of patients with high (TG ³ 200 mg/dL and <500 mg/dL) triglyceride levels who are also on statin therapy for elevated low-density lipoprotein cholesterol, or LDL-C, levels which we refer to as mixed dyslipidemia. We refer to this second proposed indication for Vascepa as the ANCHOR indication. In late February 2013, we submitted a Supplemental New Drug Application, or sNDA, for the ANCHOR indication with the FDA. If our sNDA is accepted by the FDA, assuming a ten-month FDA review period, we expect the FDA to assign a Prescription Drug User Fee Act, or PDUFA, action date which is not later than the end of 2013.

In December 2011, we announced commencement of patient dosing in our cardiovascular outcomes study of Vascepa, titled REDUCE-IT (Reduction of Cardiovascular Events with EPA—Intervention Trial), that is designed to evaluate the efficacy of Vascepa in reducing major cardiovascular events in a high risk patient population on statin therapy. Based on communications with the FDA, we believe that we are required to be “substantially underway” with a cardiovascular outcomes study at the time of the submission of our sNDA seeking approval of the ANCHOR indication. We believe that we achieved this requirement prior to submitting the sNDA. However, there can be no assurance that the FDA will agree with our assessment or that they will accept our sNDA for the ANCHOR indication. We do not believe the final results of the REDUCE-IT study will be required for FDA approval of Vascepa for the ANCHOR indication.

Hypertriglyceridemia refers to a condition in which patients have high levels of triglycerides in the bloodstream. Triglycerides are fats in the blood. It is estimated that over 40 million adults in the United States

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have elevated triglyceride levels greater than 200mg/dL and approximately 4.0 million people in the United States have severely high (TG ³500mg/dL) triglyceride levels, commonly known as very high triglyceride levels. According to The American Heart Association Scientific Statement on Triglycerides and Cardiovascular Disease (2011), triglycerides also provide important information as a marker associated with the risk for heart disease and stroke, especially when an individual also has low high-density lipoprotein, or HDL-C (often referred to as “good” cholesterol), and elevated levels of LDL-C (often referred to as “bad” cholesterol). Guidelines for the management of very high triglyceride levels suggest that reducing triglyceride levels is the primary goal in patients to reduce the risk of acute pancreatitis. The effect of Vascepa on cardiovascular mortality and morbidity in patients with hypertriglyceridemia has not been determined. The effect of Vascepa on the risk for pancreatitis in patients with hypertriglyceridemia has not been determined.

The potential efficacy and safety of Vascepa was studied in two Phase 3 clinical trials, the MARINE trial and the ANCHOR trial. At a daily dose of 4 grams of Vascepa, the dose at which Vascepa is FDA approved, these trials showed favorable clinical results in their respective patient populations in reducing triglyceride levels without increasing LDL-C levels in the MARINE trial and with a statistically significant decrease in LDL-C levels in the ANCHOR trial. These trials also showed favorable results, particularly with the 4-gram dose of Vascepa, in other important lipid and inflammation biomarkers, including apolipoprotein B (apo B), non-high-density lipoprotein cholesterol (non-HDL-C), total-cholesterol (TC), very low-density lipoprotein cholesterol (VLDL-C), lipoprotein-associated phospholipase A2 (Lp-PLA2), and high sensitivity C-reactive protein (hs-CRP). In these trials, the most commonly reported adverse reaction (incidence >2% and greater than placebo) in Vascepa-treated patients was arthralgia (joint pain) (2.3% for Vascepa vs. 1.0% for placebo).

Commercialization of Vascepa

Vascepa became commercially available in the United States by prescription in January 2013, when we commenced sales and shipments to our network of U.S.-based wholesalers. On January 28, 2013, we commenced our full commercial launch of Vascepa in the United States for use in the MARINE indication. In preparation for our commercial launch, we recently hired and trained a direct sales force of approximately 275 sales representatives. We also employ various marketing and medical affairs personnel to support our commercialization of Vascepa. Our clinical and commercial supply is provided to us under agreements with various third-party suppliers. As of the date of this Annual Report, we have announced that 18 patent applications in the United States have been either issued or allowed and more than 30 additional patent applications are pending in the United States. We are also pursuing patent applications related to Vascepa in multiple jurisdictions outside the United States. These patent applications are part of our strategy to protect the commercial potential of Vascepa, which generally includes obtaining and maintaining intellectual property rights, maintaining trade secrets, seeking regulatory exclusivity and taking advantage of manufacturing barriers to entry.

We believe that our sales and marketing teams are well positioned to support the commercialization of Vascepa for the MARINE indication. We also believe that a larger sales effort will be required to best support the commercialization of Vascepa for the ANCHOR indication, assuming FDA approval of the ANCHOR indication. To support the continued commercialization of Vascepa, we intend to consider strategic opportunities with larger pharmaceutical companies. From time to time we have held discussions with larger pharmaceutical companies on potential collaborations and other strategic opportunities, and we intend to continue having discussions regarding such opportunities in the future. These strategic opportunities may include licensing or similar transactions, joint ventures, partnerships, strategic alliances, business associations, or a sale of the company. However, we cannot estimate the timing of any such potential strategic transaction, and no assurance can be given that we will enter into any such strategic transaction. Until such time when we enter into such a strategic transaction, if ever, we plan to continue to execute on our plans to market and sell Vascepa on our own.

The U.S. market is currently our primary focus for Vascepa. Opportunities to seek regulatory approval and to market and sell Vascepa outside of the United States are also under evaluation.

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Financial Position

We believe that our cash balance of $260.2 million at December 31, 2012 is sufficient to fund our projected operations for at least the next twelve months, including commercialization of Vascepa in the United States for the MARINE indication, preparations for commercialization of Vascepa in the United States for the ANCHOR indication and the advancement of the REDUCE-IT cardiovascular outcomes study. In order to fund our commercialization plans, in particular to fully support the launch, marketing and sale of Vascepa in the ANCHOR indication, we will likely need enter into a strategic collaboration or raise additional capital.

Lipid Disorders and Cardiovascular Disease

Heart attacks, strokes and other cardiovascular events represent the leading cause of death and disability among men and women in western societies. According to the 2012 At-A-Glance Report from the U.S. Center for Disease Control, more than 1 out of every 3 adults in the U.S. (approximately 83 million) currently lives with one or more types of cardiovascular disease; an estimated 935,000 heart attacks and 795,000 strokes occur each year; an estimated 71 million adults have high cholesterol (i.e. high levels of low-density lipoprotein cholesterol, or LDL-C); and only 1 out of 3 adults with high LDL cholesterol has the condition under control.

Hypertriglyceridemia refers to a condition in which patients have high levels of triglycerides in the bloodstream and has been recognized as an independent risk factor for cardiovascular disease. Triglyceride levels provide important information as a marker associated with the risk for heart disease and stroke, especially when an individual also has low HDL-C and elevated levels of LDL-C. The effect of Vascepa on cardiovascular mortality and morbidity in patients with hypertriglyceridemia has not been determined.

Guidelines for the management of very high triglyceride levels (>500 mg/dL) suggest that reducing triglyceride levels is the primary goal in patients to reduce the risk of acute pancreatitis. Under these guidelines, targeting LDL-C goal for all patients remains important. Other important parameters to consider in patients with very high TGs include levels of apo B, non—HDL-C, VLDL-C, TC, and HDL-C. The effect of Vascepa on the risk for pancreatitis in patients with hypertriglyceridemia has not been determined.

It is estimated that over 40 million adults in the United States have elevated triglyceride levels >200mg/dL and approximately 4.0 million people in the United States have very high triglyceride levels (>500 mg/dL). Since 1976, mean triglyceride levels have increased, in concert with the growing epidemic of obesity, insulin resistance, and type 2 diabetes mellitus. In contrast, mean LDL-C levels have decreased.

Mixed dyslipidemia refers to a condition in which patients have a combination of two or more lipid abnormalities including elevated triglycerides, low HDL-C, and/or elevated LDL-C. Both hypertriglyceridemia and mixed dyslipidemia are components of a range of lipid disorders collectively referred to as dyslipidemia. Dyslipidemia has been linked to atherosclerosis, commonly referred to as hardening of the arteries.

Limitations of Current Therapies

It is estimated that fewer than 4% of U.S. adults with triglyceride levels ³ 200 mg/dL are currently receiving prescription medication for lowering triglycerides. Many of these patients are taking statin therapy directed primarily at lowering their LDL-C levels.

The leading treatments to lower triglyceride levels are fibrates (fenofibrate and gemfibrozil), statins and a prescription only omega-3 fatty acid, known as Lovaza^® in the United States, and as Omacor^® in Europe. The use of fenofibrates can lead to abnormal liver function tests (an increase in ALT (alanine transaminase) or AST (aspartate transaminase), which are liver enzymes, and are commonly measured clinically as a part of a diagnostic liver function test to determine liver health), especially when used with statins. The use of gemfibrozil can lead to rhabdomyolysis (severe breakdown of muscles), especially when used with a statin. Lovaza is comprised of omega-3 ethyl esters, which the FDA has described as a complex mixture of eicosapentanoic acid,

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or EPA, docosahexaenoic acid, or DHA, and other fatty acids. We believe that DHA may increase LDL-C levels and thereby partially offset one of the typically desired benefits of lipid-lowering therapies, which is lowering LDL-C. Also, in 2012, the FDA required an update to Lovaza product labeling to reflect the risk that Lovaza may increase the frequency of a heart rhythm problem known as atrial fibrillation, or heart flutter.

Potential Benefits and Market Opportunity for Vascepa

Vascepa is comprised of not less than 96% pure icosapent ethyl, or ethyl-EPA, and contains no DHA. We believe that the removal of DHA mitigates against the LDL-C raising effect observed in omega-3 formulations that include DHA, as well removing the fishy taste and smell that is sometimes associated with DHA. Based on the results of the MARINE trial, Vascepa was the first omega-3 based product to demonstrate statistically significant triglyceride reduction without a statistically significant increase in LDL-C in this very high triglyceride population.

We believe that the results of the MARINE trial and Vascepa’s EPA only/DHA-free composition suggest that Vascepa has the potential to become a “best-in-class” triglyceride-lowering agent in the United States and the European Union. In addition, currently no omega-3 based product is approved in the United States for lowering high triglycerides in patients with mixed dyslipidemia. We believe that Vascepa has the potential to become “first-in-class” in the prescription-only omega-3 market for lowering triglycerides in patients with mixed dyslipidemia.

We believe the potential market for Vascepa is large and growing. We estimate that drug treatment for hypercholesterolemia patients exceeds $53 billion per year in the United States, with sales dominated by statin therapies. U.S. sales of fibrates as a class of products were approximately $3.1 billion in 2012 with Tricor and Trilipix leading the class. U.S. gross sales of Lovaza in 2012 were over $1.3 billion.

Commercialization of Vascepa

Vascepa became commercially available in the United States by prescription in January 2013, when we commenced sales and shipments to our network of U.S.-based wholesalers. On January 28, 2013, we commenced our full commercial launch of Vascepa in the United States for use in the MARINE indication. In preparation for our commercial launch, we recently hired and trained a direct sales force of approximately 275 sales representatives. We also employ various marketing and medical affairs personnel to support our commercialization of Vascepa. We continue to conduct the REDUCE-IT trial and will consider additional trials to further expand the potential indications of use for Vascepa. We do not believe the final results of our REDUCE-IT cardiovascular outcomes study will be required for FDA approval of Vascepa for use in the ANCHOR indication.

We believe that our sales and marketing teams are well positioned to support the commercialization of Vascepa for the MARINE indication. We also believe that a larger sales force will be required to best support the commercialization of Vascepa for the ANCHOR indication, assuming FDA approval for the ANCHOR indication. To support the continued commercialization of Vascepa, we intend to consider strategic opportunities with larger pharmaceutical companies. From time to time we have held discussions with larger pharmaceutical companies on potential collaborations and other strategic opportunities, and we intend to continue having discussions regarding such opportunities in the future. These strategic opportunities may include licensing or similar transactions, joint ventures, partnerships, strategic alliances, business associations, or a sale of the company. However, we cannot estimate the timing of any such potential strategic transaction and no assurance can be given that we will enter into any such strategic transaction. Until such time when we enter into such a strategic transaction, if ever, we plan to continue to execute on our plans to market and sell Vascepa on our own.

The U.S. market is currently our primary focus for Vascepa. Opportunities to seek regulatory approval of, and market and sell, Vascepa outside of the United States are also under evaluation.

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Clinical Trials

The MARINE Trial

The MARINE trial, the largest study ever conducted with the omega-3 fatty acid ethyl EPA in treating patients with very high triglycerides (³500 mg/dL), was a Phase 3, multi-center, placebo-controlled, randomized, double-blind, 12-week study. Patients were randomized into three treatment arms for treatment with Vascepa 4 gram/day, 2 gram/day or placebo. Patient enrollment in this trial began in December 2009, and enrollment and randomization was completed in August 2010 at 229 patients. The primary endpoint in the trial was the percentage change in triglyceride level from baseline compared to placebo after 12 weeks of treatment. The MARINE study was required to meet a stringent level of statistical significance of 1% (p < 0.01) in our Special Protocol Assessment, or SPA, agreement with the FDA.

On November 29, 2010, we reported top-line data for the MARINE trial. In the trial, Vascepa met its primary endpoint at doses of 4 grams and 2 grams per day with median placebo-adjusted reductions in triglyceride levels of 33% (p < 0.0001) compared to placebo for 4 grams and 20% (p = 0.0051) compared to placebo for 2 grams. The median baseline triglyceride levels were 703 mg/dL, 680 mg/dL and 657 mg/dL for the patient groups treated with placebo, 4 grams of Vascepa and 2 grams of Vascepa, respectively.

In a pre-specified secondary analysis in the subgroup of patients with baseline triglyceride > 750 mg/dL, representing 39% of all patients, the effect of Vascepa in reducing triglyceride levels compared to placebo was 45% for 4 grams and 33% for 2 grams, both statistically significant (p = 0.0001 for 4 grams and p= 0.0016 for 2 grams, respectively). The median baseline triglyceride levels in this subgroup were 1052 mg/dL, 902 mg/dL and 948 mg/dL for placebo, 4-gram and 2-gram groups, respectively. Twenty-five percent of patients in this trial were also on background statin therapy. These patients had greater median reduction in triglyceride levels, which was also statistically significant.

Importantly, the significant reduction in triglycerides was not associated with a statistically significant increase in median LDL-C compared to placebo at either dose (-2.3% for the 4-gram group and +5.2% for the 2-gram group [both p=NS]). In addition, there was a statistically significant decrease in median non-HDL-C (total cholesterol less so-called “good cholesterol”) compared to placebo with both of the Vascepa treated groups (-18% for the 4-gram group [p < 0.001] and -8% for the 2-gram group [p < 0.05]).

The MARINE trial results also included statistically significant reductions compared to placebo in several important lipid and inflammatory biomarkers, including apo B (apolipoprotein B) (8.5%), Lp-PLA2 (lipoprotein-phospholipase A2) (13.6%), VLDL-C (very low-density lipoprotein cholesterol) (28.6%), Total Cholesterol (16.3%), and hsCRP (high-sensitivity C-reactive protein) (36.0%) at the 4-gram dose. For these achieved endpoints, p-values were <0.01 for most and <0.05 for all. Apo B (apolipoprotein B) is believed to be a sensitive biomarker of cardiovascular risk and may be a better predictor of cardiovascular risk than LDL-C. Lp-PLA2 is an enzyme found in blood and atherosclerotic plaque; high levels have been implicated in the development and progression of atherosclerosis.

In the MARINE trial, patients treated with 4 grams per day of Vascepa experienced a significant reduction in median placebo-adjusted lipoprotein particle concentrations of total LDL and small LDL. When looking at lipoprotein particle concentrations and sizes as measured with nuclear magnetic resonance spectroscopy, Vascepa 4 grams per day, compared with placebo, significantly reduced median total LDL particle count by 16.3% (p=0.0006), which is an important factor in atherogenesis. LDL particle count and apo B are important risk markers for the prediction of cardiovascular events. Small LDL particle count, which is a common risk factor for cardiovascular events in patients with diabetes, was reduced by 25.6% (p<0.0001) compared with placebo. Vascepa 2 grams per day, compared with placebo, significantly reduced median small LDL particle count by 12.8% (p <0.05) and reduced median total LDL particle count by 1.1% (NS). LDL particle size did not change significantly for the 2 or 4 grams doses.

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Vascepa was well tolerated in the MARINE trial, with a safety profile comparable to placebo and there were no treatment-related serious adverse events observed. No significant changes in fasting blood glucose, hemoglobin A1C, vital signs, electrocardiograms, or liver or kidney function were observed with either Vascepa dose.

Patients enrolled in the MARINE trial were given the option to be treated with Vascepa for a period of up to 40 weeks after their last dose in the double-blind portion of the trial. Once participants completed the randomized, double blind, placebo-controlled 12-week MARINE registration trial, patients in all three randomized groups (4 grams, 2 grams and placebo) were offered the opportunity to participate in the open label extension, or OLE, phase. Patients in the OLE phase received 4 grams per day of Vascepa for a period of up to an additional 40 weeks. As is typical of such extension phases, the OLE phase was not a controlled trial, as differentiated from the randomized, double blind, placebo-controlled 12-week MARINE registration trial. In the OLE phase, participants were not randomized at entry, Vascepa administration was open-label (and thus not blinded), and no placebo group was maintained. Also, once patients entered in the OLE phase, investigators were free to add or modify other lipid-altering nutritional, lifestyle and drug treatment regimens. Given the lack of randomization, the open-label design, the addition of various other lipid-altering drugs and changes to doses of existing lipid-altering drugs, as well as the lack of placebo control, neither we nor our independent advisors were able to draw efficacy conclusions from the data. However, we have concluded that the MARINE OLE phase revealed no new safety signals after an additional 40 weeks of exposure to Vascepa, whether used alone or in combination with other lipid-altering regimens.

The ANCHOR Trial

The ANCHOR trial was a multi-center, placebo-controlled, randomized, double-blind, 12-week pivotal study in patients with high triglycerides ( ³ 200 and <500 mg/dL) who were also receiving optimized statin therapy. Patients were randomized into three arms for treatment with Vascepa 4 gram/day, 2 gram/day or placebo. Patient enrollment in this trial began in January 2010, and enrollment and randomization was completed in February 2011 at 702 patients. The primary endpoint in the trial was the percentage change in triglyceride level from baseline compared to placebo after 12 weeks of treatment.

In April 2011, we reported top-line results from the ANCHOR trial. The ANCHOR trial met its primary endpoint at doses of 4 grams and 2 grams per day with median placebo-adjusted reductions in triglyceride levels of 21.5% (p<0.0001 value) for 4 grams and 10.1% (p=0.0005) for 2 grams. The median baseline triglyceride levels were 259 mg/dL, 265 mg/dL and 254 mg/dL for the patient groups treated with placebo, 4 grams and 2 grams of Vascepa per day, respectively. The analysis of subgroups by baseline triglyceride tertiles showed that higher baseline triglycerides resulted in greater triglyceride reductions.

One of the trial’s secondary endpoints was to demonstrate a lack of elevation in LDL-C, the primary target of cholesterol lowering therapy. The trial’s non-inferiority criterion for LDL-C was met at both Vascepa doses. The upper confidence boundaries for both doses were below the pre-specified +6% LDL-C threshold limit. At the 4-gram dose the upper confidence boundary was below zero (-1.7%) and at the 2-gram dose the upper confidence boundary was close to zero (0.5%). For the 4 grams per day group, LDL-C decreased significantly by 6.2% from baseline versus placebo, demonstrating superiority over placebo (p=0.0067). For the 2-gram group, LDL-C decreased by 3.6% from baseline versus placebo (p=0.0867), which is not a statistically significant decrease.

Other secondary efficacy endpoints included the median placebo-adjusted percent change in non-high-density lipoprotein cholesterol (non-HDL-C), apolipoprotein B (apo B), and lipoprotein-associated phospholipase A2 (Lp-PLA2). The 4-gram dose was associated with statistically significant reductions in non-HDL-C (13.6%, p<0.0001), apo B (9.3%, p<0.0001), Lp-PLA2 (19%, p<0.0001) and high-sensitivity C-reactive protein (hsCRP) (22%, p<0.001), at week 12 compared to placebo. In addition to the previously reported favorable lipid effects of Vascepa on hypertriglyceridemic patients in the MARINE and ANCHOR studies, a recently published analysis of these studies showed that the Vascepa 4-gram daily dose also significantly decreased levels of the inflammatory marker oxidized low-density lipoprotein relative to placebo.

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Vascepa was well tolerated in the ANCHOR trial with a safety profile comparable to placebo and there were no treatment-related serious adverse events observed. No significant changes in fasting blood glucose, hemoglobin A1C, vital signs, electrocardiograms, or liver or kidney function were observed with either Vascepa dose.

Observed Efficacy of Ethyl-EPA

In Japan, ethyl-EPA is marketed under the product name of Epadel by Mochida Pharmaceutical Co. and is indicated for hyperlipidemia and peripheral vascular disease. Clinical data from Japan suggests that Epadel is effective in reducing triglycerides. In addition, in an outcomes study called the Japan EPA Lipid Intervention Study, or JELIS study, which consisted of more than 18,000 patients followed over multiple years, Epadel, when used in conjunction with statins, was shown to reduce cardiovascular events by 19% compared to the use of statins alone. In this study, cardiovascular events decreased by approximately 53% compared to statins alone in the subset of patients with triglyceride levels of ³ 150 mg/dL (average 269 mg/dL at entry) and HDL-C <40 mg/dL.

Observed Clinical Safety of Vascepa

Prior to commencing the MARINE and ANCHOR trials, we conducted a pre-clinical program for Vascepa, including toxicology and pharmacology studies. In addition, we previously investigated Vascepa in central nervous system disorders in several double-blind, placebo-controlled studies, including Phase 3 trials in Huntington’s disease. Over 1,000 patients have been dosed with Vascepa in these studies, with over 100 receiving continuous treatment for a year or more. In all studies performed to date, Vascepa has shown a favorable safety and tolerability profile. In both the MARINE and ANCHOR trials, patients dosed with Vascepa demonstrated a safety profile similar to placebo. There were no treatment-related serious adverse events in the MARINE study or in the ANCHOR study. In the MARINE and ANCHOR trials, the most commonly reported adverse reaction (incidence >2% and greater than placebo) in Vascepa treated patients was arthralgia (joint pain) (2.3% for Vascepa vs. 1.0% for placebo).

In addition to the MARINE and ANCHOR trials, we completed a 28-day pharmacokinetic study in healthy volunteers, a 26-week study to evaluate the toxicity of Vascepa in transgenic mice and multiple pharmacokinetic drug-drug interaction studies in healthy subjects in which we evaluated the effect of Vascepa on certain common prescription drugs. All findings from these studies were consistent with our expectations and confirmed the overall safety profile of Vascepa.

The REDUCE-IT Study

In August 2011, we reached agreement with the FDA on an SPA for the design of the REDUCE-IT (Reduction of Cardiovascular Events with EPA—Intervention Trial) cardiovascular outcomes study. An SPA is an evaluation by the FDA of a protocol with the goal of reaching an agreement that the Phase 3 trial protocol design, clinical endpoints, and statistical analyses are acceptable to support regulatory approval. The FDA agreed that, based on the information we submitted to the agency, the design and planned analysis of the REDUCE-IT study adequately addressed the objectives necessary to support a regulatory submission. An SPA is generally binding upon the FDA unless a substantial scientific issue essential to determining safety or efficacy is identified after the testing begins. Moreover, any change to a study protocol can invalidate an SPA. There can be no assurance that the FDA will ultimately consider our SPA to be binding. If the FDA does not consider the SPA to be binding or makes a determination that we did not follow the SPA appropriately, the agency could assert that additional studies or data are required to support a regulatory submission.

In September 2011, we engaged a clinical research organization, or CRO, and began initial trial and clinical site preparation for REDUCE-IT. In December 2011, we announced that the first patient was dosed in the study.

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The study duration is dependent on the rate of clinical events in the study which rate may be affected by the number of patients enrolled in the study and the epidemiology of the patients enrolled in the study. Based on preliminary assumptions for patient enrollment rates and the clinical profile of these patients, it is assumed that fewer than 10,000 patients will be required to complete the study with an optimized target in which the study is completed in approximately six years of 8,000 patients.

The REDUCE-IT study is designed to evaluate the efficacy of Vascepa in reducing major cardiovascular events in an at-risk patient population also receiving statin therapy. REDUCE-IT is a multi-center, prospective, randomized, double-blind, placebo-controlled, parallel-group study to evaluate the effectiveness of Vascepa, as an add-on to statin therapy, in reducing first major cardiovascular events in an at-risk patient population compared to statin therapy alone. The control arm of the study is comprised of patients on optimized statin therapy. The active arm of the study is comprised of patients on optimized statin therapy plus Vascepa. All subjects enrolled in the study will have elevated triglyceride levels and either coronary heart disease or risk factors for coronary heart disease. This study will be conducted internationally. Based on the results of REDUCE-IT, we may seek additional indications for Vascepa beyond the indication studied in the ANCHOR and MARINE trials such as a potential indication for prevention of cardiovascular events, although there can be no assurance as to whether the results of the study will support any such indication.

New Lipid Compounds and other Preclinical Programs

We are also considering development of other next generation compounds based on our internal lipid science expertise, including potential combination and derivative therapies.

In December 2012, we completed dosing and pharmacokinetic sampling in a study to test a fixed-dose combination of Vascepa capsules and a leading statin. The clinical name for this combination product candidate is AMR102. The purpose of the AMR102 study is to determine the bioavailability of the Vascepa and statin components when taken as a fixed-dose combination product, relative to the individual reference agents taken concomitantly. We anticipate reviewing the results of this study in the first half of 2013.

We believe that Vascepa and other lipid-based compositions may have an impact on a number of biological factors in the body such as anti-inflammatory mechanisms, cell membrane composition and plasticity, triglyceride levels and regulation of glucose metabolism. Currently all other clinic developments are in formulative or pre-clinical stages.

Manufacturing and Supply for Vascepa

We currently use third party manufacturers and suppliers to manufacture clinical and commercial quantities of ethyl-EPA, which constitutes the only active pharmaceutical ingredient, or API, within Vascepa, to encapsulate, bottle and package Vascepa and to maintain inventory of Vascepa. The approval of Vascepa in July 2012 included the approval of one active pharmaceutical ingredient, or API, manufacturer, Nisshin Pharma, Inc., and one API encapsulator, Patheon, Inc. (formerly Banner Pharmacaps Europe BV). Nisshin and Patheon are the API manufacturer and API encapsulator, respectively, with which we have had the longest working relationships. Their facilities were inspected by regulatory authorities as part of the process that led to the FDA’s July 2012 approval of Vascepa, and we believe that the facilities are qualified to support our commercial launch of Vascepa. In October 2012, a second API encapsulator, Catalent Pharma Solutions LLC, was qualified to encapsulate API for Vascepa.

The API material that constitutes ethyl-EPA is a naturally occurring substance which is sourced from qualified producers of fish oil. A limited number of other manufacturers have the ability, know-how and suitable facilities to produce ethyl-EPA to a similar level of purity. Among the conditions for FDA approval of a pharmaceutical product is the requirement that the manufacturer’s quality control and manufacturing procedures conform to current Good Manufacturing Practice, or cGMP, which must be followed at all times. The FDA typically inspects manufacturing facilities before regulatory approval of a product candidate, such as Vascepa,

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and on an ongoing basis. In complying with cGMP regulations, pharmaceutical manufacturers must expend resources and time to ensure compliance with product specifications as well as production, record keeping, quality control, reporting, and other requirements.

Our goal is to expand our supply chain to provide greater capacity to meet anticipated demand, enable supply diversification and flexibility and introduce cost competition. We have defined with the FDA our plan and specifications for qualifying the additional API suppliers. We intend to submit sNDAs for the use of additional API suppliers after the suppliers successfully complete the specified process and facility qualifications. However, Nisshin is currently our only supplier of Vascepa API. In 2011, after conducting an extensive global search for manufacturers capable of producing Vascepa API to our technical specifications, we entered into limited exclusivity, long-term agreements with two additional API suppliers, Chemport, Inc. and BASF (formerly Equateq Limited). In December 2012, we announced an agreement with an exclusive consortium of companies led by Slanmhor Pharmaceutical, Inc. Slanmhor was spun-out from Ocean Nutrition Canada (ONC) prior to the May 2012 acquisition of ONC by Royal DSM N.V., a global leader in life sciences and materials sciences.

In December 2012, we announced our submissions of two sNDAs to the FDA seeking approval for Chemport and BASF as additional Vascepa API suppliers. We intend to submit an additional sNDA for Slanmhor after it successfully completes the qualification process. Subject to appropriate regulatory approvals, the addition of Slanmhor would give us a total of four qualified worldwide suppliers of API for Vascepa to utilize in supporting the global commercialization of Vascepa.

Our agreements with our API suppliers include annual purchase levels to enable Amarin to maintain exclusivity with each respective supplier and to prevent potential termination of the agreements. Certain of these agreements also contain provisions under which the cost of supply to us decreases as we purchase increased product volume. The agreements with each of our API suppliers that have not yet been approved by the FDA also contemplate phased capacity expansion aimed at creating sufficient capacity to meet anticipated demand for API material for Vascepa. Accordingly, these suppliers are currently working to expand their production capabilities to manufacture the API for Vascepa. These API suppliers are self-funding these expansion and qualification plans with contributions from Amarin. There can be no assurance that additional suppliers will fully-fund the capital costs of our engagement or that these additional suppliers will successfully qualify with the FDA.

We intend to purchase increasing amounts of API to support the commercial launch of Vascepa. Our supply agreement with Nisshin contains minimum purchase commitments for metric tons of API, and we may purchase more than the minimum requirement. We received the majority of this API during 2012, in advance of our planned commercial launch of Vascepa. During 2013, we intend to further increase our purchases of API and finished capsules of Vascepa. These purchases are generally made on the basis of rolling twelve-month forecasts which in part are binding on us and the balance of which are subject to adjustment by us subject to certain limitations. We may elect to make certain of these purchases prior to sNDA approval of our added suppliers after we are satisfied that the material they produce and their facilities are qualified. However, in the event that we make such purchases, we will not be able to use such material for commercial sale until the sNDA for the applicable supplier is approved by the FDA. Similarly, if we are not compliant with other regulations with regard to this intended purchase of supply, the supply of product may be delayed.

Our strategy is to expand capacity and to mitigate risk by having multiple API suppliers. Our aggregate capacity to produce API is dependent upon the qualification of our API suppliers. Each of our API suppliers has outlined plans for potential further capacity expansion. We anticipate purchasing qualified API from multiple suppliers for our first year of commercial sales of Vascepa, including purchases from BASF, Chemport and/or Slanmhor prior to FDA approval of the respective sNDAs for these suppliers. If an sNDA for any of these three API suppliers is not approved, we will not be able to use the supply from such supplier for commercial product. Also, if no additional API supplier is approved by the FDA, our API supply will be limited to the API we purchase from Nisshin. We believe that our overall API manufacturing plan provides a pathway to the production of API in sufficient quantities to meet anticipated demand, subject to API supplier capacity expansion,

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qualification and regulatory approval. There can be no assurance that these expansion plans will be successful. If our third party manufacturing capacity is not expanded and compliant with application regulatory requirements, we may not be able to supply sufficient quantities of Vascepa to meet anticipated demand. Our purchase of supply may be insufficient to meet, or exceed, actual demand for Vascepa.

Our Marketing Plans

We are currently expanding our marketing, sales and distribution capabilities. In early 2013 we hired and trained approximately 275 sales representatives in the United States. Vascepa became commercially available in the United States by prescription in January 2013, when we commenced sales and shipments to our network of U.S.-based wholesalers. On January 28, 2013, we commenced our full commercial launch of Vascepa for use in the MARINE indication. We are initially targeting clinicians who are top prescribers of lipid regulating therapies.

Historical Product Development Programs

Prior to October 2009, the majority of Amarin’s product development activities were focused on central nervous system and other non-cardiovascular disorders. In October 2009, we completed a private placement resulting in gross proceeds of $70.0 million. These proceeds were used primarily to fund the MARINE and ANCHOR studies for Vascepa. In connection with this private placement, our board of directors and executive management underwent significant change, and our research and development activities, as well as certain executive functions, were consolidated from multiple offices to our research and development headquarters in the United States. In connection with these changes, we re-focused our efforts on developing improved treatments for cardiovascular disease and ceased development of all product candidates outside of our cardiovascular disease focus. In particular, this decision resulted in our ceasing all direct development of product candidates on central nervous system disorders, which included product candidates for the treatment of Huntington’s disease, Myasthenia gravis and Parkinson’s disease.

Competition

The biotechnology and pharmaceutical industries are highly competitive. There are many pharmaceutical companies, biotechnology companies, public and private universities and research organizations actively engaged in the research and development of products that may be similar to our products. It is probable that the number of companies seeking to develop products and therapies similar to our products will increase. Many of these and other existing or potential competitors have substantially greater financial, technical and human resources than we do and may be better equipped to develop, manufacture and market products. These companies may develop and introduce products and processes competitive with or superior to ours. In addition, other technologies or products may be developed that have an entirely different approach or means of accomplishing the intended purposes of our products, which might render our technology and products noncompetitive or obsolete.

Our potential competitors both in the United States and Europe include large, well-established pharmaceutical companies, specialty pharmaceutical sales and marketing companies and specialized cardiovascular treatment companies. These companies include GlaxoSmithKline plc, which currently markets Lovaza, a prescription-only omega-3 fatty acid indicated for patients with very high triglycerides, and Abbott Laboratories, which currently markets Tricor, Trilipix and Niaspan for the treatment of very high triglycerides and mixed dyslipidemia and Niaspan, which is primarily used to increase HDL-C, but which is also used to lower triglycerides. In March 2011, Pronova BioPharma Norge AS, which owns the patents for Lovaza, entered into an agreement with Apotex Corp. and Apotex Inc. to settle their patent litigation in the United States related to Lovaza. Pursuant to the terms of the settlement agreement, Pronova granted Apotex a license to enter the U.S. market with a generic version of Lovaza in the first quarter of 2015, or earlier, depending on circumstances. We expect Apotex to compete against us as well. Other companies are also seeking to introduce generic versions of Lovaza.

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In addition, we are aware of other pharmaceutical companies that are developing products that, if approved, would compete with Vascepa. These include a free fatty acid form of omega-3 (comprised of 55% EPA and 20% DHA) which is being developed by Omthera Pharmaceuticals which in April 2012 announced its top-line Phase 3 clinical trial results and indicated that it plans to submit an NDA during 2013 for the treatment of hypertriglyceridemia. In addition, Acasti Pharma, a subsidiary of Neptune Technologies & Bioresources Inc., announced in December 2012 that it intends to conduct a Phase 3 clinical program to assess the safety and efficacy of its omega-3 prescription drug candidate derived from krill oil for the treatment of hypertriglyceridemia. We believe Resolvyx Pharmaceuticals and Catabasis Pharmaceuticals are also developing potential treatments for hypertriglyceridemia based on omega-3 fatty acids, but we believe that neither has initiated a Phase 2 clinical trial of its product. In addition, we are aware that Essentialis, Inc is developing a controlled release diazoxide product for the treatment of hypertriglyceridemia. Essentialis, Inc. has reported that they have completed Phase 2 clinical studies with this product.

Vascepa will also face competition from dietary supplement companies marketing naturally occurring omega-3 fatty acids as nutritional supplements. We cannot be sure physicians and pharmacists will view the FDA-approved prescription-only status, EPA-only purity of Vascepa and stringent regulatory oversight as significant advantages versus naturally occurring omega-3 fatty acid dietary supplements.

In addition, other drug companies, known as generic drug companies, may challenge the validity, enforceability or both of our patents and seek to design products around our issued patent claims and, after a period of FDA-granted regulatory exclusivity gain marketing approval for generic versions of Vascepa or gain marketing approval for branded competitive products based on new clinical studies.

Regulatory Matters

Government Regulation and Regulatory Matters

Any product development activities related to Vascepa or products that we may develop or acquire in the future will be subject to extensive regulation by various government authorities, including the FDA and comparable regulatory authorities in other countries, which regulate the design, research, clinical and non-clinical development, testing, manufacturing, storage, distribution, import, export, labeling, advertising and marketing of pharmaceutical products and devices. Generally, before a new drug can be sold, considerable data demonstrating its quality, safety and efficacy must be obtained, organized into a format specific to each regulatory authority, submitted for review and approved by the regulatory authority. The data is generated in two distinct development stages: pre-clinical and clinical. Our drugs must be approved by the FDA through the NDA process before they may be legally marketed in the United States. For new chemical entities, the pre-clinical development stage generally involves synthesizing the active component, developing the formulation and determining the manufacturing process, as well as carrying out non-human toxicology, pharmacology and drug metabolism studies which support subsequent clinical testing.

The clinical stage of development can generally be divided into Phase 1, Phase 2 and Phase 3 clinical trials. In Phase 1, generally, a small number of healthy volunteers are initially exposed to a single dose and then multiple doses of the product candidate. The primary purpose of these studies is to assess the metabolism, pharmacologic action, side effect tolerability and safety of the drug. Phase 2 trials typically involve studies in disease-affected patients to determine the dose required to produce the desired benefits. At the same time, safety and further pharmacokinetic and pharmacodynamic information is collected. Phase 3 trials generally involve large numbers of patients at multiple sites, in multiple countries and are designed to provide the pivotal data necessary to demonstrate the effectiveness of the product for its intended use, its safety in use, and may include comparisons with placebo and/or other comparator treatments. The duration of treatment is often extended to mimic the actual use of a product during marketing.

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United States Drug Development

In the United States, 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. Failure to comply with the applicable United States requirements at any time during the product development process, approval process or after approval, may subject an applicant to administrative or judicial sanctions. These sanctions could include the FDA’s refusal to approve pending applications, withdrawal of an approval, a clinical hold, warning letters, product recalls, product seizures, total or partial suspension of production or distribution injunctions, fines, refusals of government contracts, restitution, disgorgement, or civil or criminal penalties. Any agency or judicial enforcement action could have a material adverse effect on us.

Prior to the start of human clinical studies for a new drug in the United States, preclinical laboratory and animal tests are often performed under the FDA’s Good Laboratory Practices regulations, or GLP, and an investigational new drug application, or IND, is filed with the FDA. Similar filings are required in other countries; however, data requirements and other information needed for a complete submission may differ in other countries. The amount of data that must be supplied in the IND depends on the phase of the study. Phase 1 studies typically require less data than larger Phase 3 studies. A clinical plan must be submitted to the FDA prior to commencement of a clinical trial. If the FDA has concerns about the clinical plan or the safety of the proposed studies, they may suspend or terminate the study at any time. Studies must be conducted in accordance with good clinical practice and regular reporting of study progress and any adverse experiences is required. Studies are also subject to review by independent institutional review boards, or IRBs, responsible for overseeing studies at particular sites and protecting human research study subjects. An independent IRB may also suspend or terminate a study once initiated.

NDA and FDA Review Process

Following trial completion, trial data is analyzed to determine safety and efficacy. Data is then filed with the FDA in an NDA along with proposed labeling for the product and information about the manufacturing and testing processes and facilities that will be used to ensure product quality. The NDA must contain proof of safety, purity, potency and efficacy, which entails extensive pre-clinical and clinical testing. FDA approval of an NDA must be obtained before marketing a drug in the United States. In addition, in order to seek approval for a potentially expanded indication based on the ANCHOR study, we are required to have been substantially enrolled subjects in our REDUCE-IT cardiovascular outcomes study at the time of our NDA submission for the ANCHOR indication. Based upon feedback from the FDA and in accordance with the SPA for the ANCHOR study, we do not believe that the results of the REDUCE-IT outcomes study are required for approval of the indication studied in the ANCHOR trial.

The FDA will likely re-analyze the clinical trial data, which could result in extensive discussions between the FDA and us during the review process. The review and evaluation of applications by the FDA is extensive and time consuming and may take longer than originally planned to complete. The FDA may conduct a pre-approval inspection of the manufacturing facilities for the new product to determine whether they comply with current good manufacturing practice requirements and may also audit data from clinical and pre-clinical trials.

There is no assurance that the FDA will ultimately approve a drug product for marketing in the United States. Even if future indications for Vascepa are approved, the FDA’s review will be lengthy and we may encounter significant difficulties or costs during the review process. After approving any drug product, the FDA may require post-marketing testing and surveillance to monitor the effects of approved products or it may place conditions on approvals including potential requirements or risk management plans that could restrict the commercial promotion, distribution, prescription or dispensing of products. Product approvals may be withdrawn for non-compliance with regulatory standards or if problems occur following initial marketing.

European Union Drug Development

In the European Union, or E.U., our future products may also be subject to extensive regulatory requirements. As in the United States, the marketing of medicinal products has been subject to the granting of

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marketing authorizations by regulatory agencies. Particular emphasis is also being placed on more sophisticated and faster procedures for reporting of adverse events to the competent authorities.

Similar to the United States, the various phases of pre-clinical and clinical research in the E.U. are subject to significant regulatory controls. Although the regulatory controls on clinical research are currently undergoing a harmonization process following the adoption of the Clinical Trials Directive 2001/20/EC, there are currently significant variations in the member state regimes. However, all member states currently require independent institutional review board approval of interventional clinical trials. With the exception of U.K. Phase 1 studies in healthy volunteers, all clinical trials require either prior governmental notification or approval. Most regulators also require the submission of adverse event reports during a study and a copy of the final study report.

European Union Drug Review and Approval

In the E.U., approval of new medicinal products can be obtained through one of three processes: the mutual recognition procedure, the centralized procedure and the decentralized procedure.

Mutual Recognition Procedure

An applicant submits an application in one E.U. member state, known as the reference member state. Once the reference member state has granted the marketing authorization, the applicant may choose to submit applications in other concerned member states, requesting them to mutually recognize the marketing authorizations already granted. Under this mutual recognition process, authorities in other concerned member states have 55 days to raise objections, which must then be resolved by discussions among the concerned member states, the reference member state and the applicant within 90 days of the commencement of the mutual recognition procedure. If any disagreement remains, all considerations by authorities in the concerned member states are suspended and the disagreement is resolved through an arbitration process. The mutual recognition procedure results in separate national marketing authorizations in the reference member state and each concerned member state.

Centralized Procedure

This procedure is currently mandatory for products developed by means of a biotechnological process and optional for new active substances and other “innovative medicinal products with novel characteristics.” Under this procedure, an application is submitted to the European Agency for the Evaluation of Medical Products. Two European Union member states are appointed to conduct an initial evaluation of each application. These countries each prepare an assessment report that is then used as the basis of a scientific opinion of the Committee on Proprietary Medical Products. If this opinion is favorable, it is sent to the European Commission, which drafts a decision. After consulting with the member states, the European Commission adopts a decision and grants a marketing authorization, which is valid throughout the European Union and confers the same rights and obligations in each of the member states as a marketing authorization granted by that member state.

Decentralized Procedure

The most recently introduced of the three processes for obtaining approval of new medicinal processes in the E.U., the decentralized procedure is similar to the mutual recognition procedure described above, but with differences in the timing that key documents are provided to concerned member states by the reference member state, the overall timing of the procedure and the possibility of “clock stops” during the procedure, among others.

Post-Marketing Requirements

Following approval of a new product, a pharmaceutical company generally must engage in numerous specific monitoring and recordkeeping activities and continue to submit periodic and other reports to the

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applicable regulatory agencies, including any cases of adverse events and appropriate quality control records. Modifications or enhancements to the products or labeling or changes of site of manufacture are often subject to the approval of the FDA and other regulators, which may or may not be received or may result in a lengthy review process.

Prescription drug advertising is subject to federal, state and foreign regulations. In the United States, the FDA regulates prescription drug promotion, including direct-to-consumer advertising. Prescription drug promotional materials must be submitted to the FDA in conjunction with their first use. Any distribution of prescription drug products and pharmaceutical samples must comply with the U.S. Prescription Drug Marketing Act, or the PDMA, a part of the U.S. Federal Food, Drug, and Cosmetic Act.

In the United States, once a product is approved, its manufacture is subject to comprehensive and continuing regulation by the FDA. The FDA regulations require that products be manufactured in specific approved facilities and in accordance with current good manufacturing practices, or cGMPs, and NDA holders must list their products and register their manufacturing establishments with the FDA. These regulations also impose certain organizational, procedural and documentation requirements with respect to manufacturing and quality assurance activities. NDA holders using contract manufacturers, laboratories or packagers are responsible for the selection and monitoring of qualified firms, and, in certain circumstances, qualified suppliers to these firms. These firms and, where applicable, their suppliers are subject to inspections by the FDA at any time, and the discovery of violative conditions, including failure to conform to cGMPs, could result in enforcement actions that interrupt the operation of any such facilities or the ability to distribute products manufactured, processed or tested by them.

Federal and State Fraud and Abuse Laws

In addition to FDA restrictions on marketing of pharmaceutical products, several other types of state and federal laws restrict certain marketing practices in the biopharmaceutical industry. These laws include anti-kickback statutes and false claims statutes.

The federal anti-kickback statute prohibits, among other things, knowingly and willfully offering, paying, soliciting, or receiving remuneration to induce or in return for a referral or the purchasing, leasing, ordering, or arranging for or recommending the purchase, lease, or order of any healthcare facility, item or service reimbursable under Medicare, Medicaid, or other federal 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 activities from prosecution, the exemptions and safe harbors are drawn narrowly, and practices that involve remuneration intended to induce prescribing, purchases, or recommendations may be subject to scrutiny if they do not qualify for an exemption or safe harbor. Our practices may not in all cases meet all of the criteria for safe harbor protection from anti-kickback liability.

Federal false claims laws prohibit any person from knowingly presenting, or causing to be presented, a false claim for payment to the federal government, or knowingly making or using, or causing to be made or used, a false statement to get a false claim paid. Recently, several pharmaceutical and other healthcare 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. The majority of states also have statutes or regulations similar to the federal anti-kickback law 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. Sanctions under these federal and state laws may include civil monetary penalties, exclusion of a manufacturer’s products from reimbursement under government programs, criminal fines, and imprisonment.

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Because of the breadth of these laws and the narrowness of the 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. As a company marketing an FDA-approved product in the United States, our operations may be directly, or indirectly through our customers, subject to various federal and state fraud and abuse laws, including, without limitation, the federal anti-kickback statute. These laws may impact, among other things, our proposed sales, marketing and education programs. In addition, we may be subject to patient privacy regulation by both the federal government and the states in which we conduct our business. The laws that may affect our ability to operate include:

If our operations are found to be in violation of any of the laws described above or any other governmental regulations that apply to us, we may be subject to penalties, including civil and criminal penalties, damages, fines and the curtailment or restructuring of our operations, any of which could adversely affect our ability to operate our business and our results of operations.

In the United States and foreign jurisdictions, there have been a number of legislative and regulatory changes to the healthcare system that could affect our future results of operations. In particular, there have been and continue to be a number of initiatives at the United States federal and state levels that seek to reduce healthcare costs. The Medicare Prescription Drug, Improvement, and Modernization Act of 2003, or the MMA, imposed new requirements for the distribution and pricing of prescription drugs for Medicare beneficiaries. Under Part D, Medicare beneficiaries may enroll in prescription drug plans offered by private entities which will provide coverage of outpatient prescription drugs. Part D plans include both stand-alone prescription drug benefit plans and prescription drug coverage as a supplement to Medicare Advantage plans. Unlike Medicare Part A and B, Part D coverage is not standardized. Part D prescription drug plan sponsors are not required to pay for all covered Part D drugs, and each drug plan can develop its own drug formulary that identifies which drugs it will cover and at what tier or level. However, Part D prescription drug formularies must include drugs within each therapeutic category and class of covered Part D drugs, though not necessarily all the drugs in each category or class. Any formulary used by a Part D prescription drug plan must be developed and reviewed by a pharmacy and therapeutic committee. Government payment for some of the costs of prescription drugs may increase demand for our products for which we receive marketing approval. However, any negotiated prices for our products covered by a Part D prescription drug plan will likely be lower than the prices we might otherwise obtain. Moreover, while the MMA applies only to drug benefits for Medicare beneficiaries, private payers often follow Medicare coverage policy and payment limitations in setting their own payment rates. Any reduction in payment that results from the MMA may result in a similar reduction in payments from non-governmental payers.

The American Recovery and Reinvestment Act of 2009 provides funding for the federal government to compare the effectiveness of different treatments for the same illness. A plan for the research will be developed by the Department of Health and Human Services, the Agency for Healthcare Research and Quality and the National Institutes for Health, and periodic reports on the status of the research and related expenditures will be made to Congress. Although the results of the comparative effectiveness studies are not intended to mandate

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coverage policies for public or private payers, it is not clear what effect, if any, the research will have on the sales of any product, if any such product or the condition that it is intended to treat is the subject of a study. It is also possible that comparative effectiveness research demonstrating benefits in a competitor’s product could adversely affect the sales of our product candidates. If third-party payers do not consider our products to be cost-effective compared to other available therapies, they may not cover our products as a benefit under their plans or, if they do, the level of payment may not be sufficient to allow us to sell our products on a profitable basis.

Most recently, in March 2010 the Patient Protection and Affordable Care Act, as amended by the Health Care and Education Reconciliation Act, or collectively the PPACA, was enacted, which includes measures to significantly change the way healthcare is financed by both governmental and private insurers. Among the provisions of the PPACA of greatest importance to the pharmaceutical and biotechnology industry are the following:

Many of the details regarding the implementation of the PPACA are yet to be determined, and at this time, it remains unclear the full effect that the PPACA would have on our business.

Other Regulatory Matters

Manufacturing, sales, promotion, and other activities following product approval are also subject to regulation by numerous regulatory authorities in addition to the FDA, including, in the United States, the Centers for Medicare & Medicaid Services, other divisions of the Department of Health and Human Services, the Drug Enforcement Administration, the Consumer Product Safety Commission, the Federal Trade Commission, the Occupational Safety & Health Administration, the Environmental Protection Agency, and state and local governments. Sales, marketing and scientific/educational programs must also comply with the U.S. Medicare-Medicaid Anti-Fraud and Abuse Act and similar state laws. Pricing and rebate programs must comply with the Medicaid rebate requirements of the U.S. Omnibus Budget Reconciliation Act of 1990. If products are made available to authorized users of the Federal Supply Schedule of the General Services Administration, additional laws and requirements apply. The handling of any controlled substances must comply with the U.S. Controlled Substances Act and Controlled Substances Import and Export Act. Products must meet applicable child-resistant packaging requirements under the U.S. Poison Prevention Packaging Act. Manufacturing, sales, promotion and other activities are also potentially subject to federal and state consumer protection and unfair competition laws.

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The distribution of pharmaceutical products is subject to additional requirements and regulations, including extensive record-keeping, licensing, storage and security requirements intended to prevent the unauthorized sale of pharmaceutical products.

The failure to comply with regulatory requirements subjects firms to possible legal or regulatory action. Depending on the circumstances, failure to meet applicable regulatory requirements can result in criminal prosecution, fines or other penalties, injunctions, recall or seizure of products, total or partial suspension of production, denial or withdrawal of product approvals, or refusal to allow a firm to enter into supply contracts, including government contracts. In addition, even if a firm complies with FDA and other requirements, new information regarding the safety or effectiveness of a product could lead the FDA to modify or withdraw a product approval. Prohibitions or restrictions on sales or withdrawal of future products marketed by us could materially affect our business in an adverse way.

Changes in regulations or statutes or the interpretation of existing regulations could impact our business in the future by requiring, for example: (i) changes to our manufacturing arrangements; (ii) additions or modifications to product labeling; (iii) the recall or discontinuation of our products; or (iv) additional record-keeping requirements. If any such changes were to be imposed, they could adversely affect the operation of our business.

Marketing Exclusivity

Market-exclusivity provisions under the Food, Drug and Cosmetic Act, or FDCA, also can delay the submission or the approval of certain applications. The FDCA provides a five-year period of non-patent marketing exclusivity within the United States to the first applicant to gain approval of an NDA for a new chemical entity, or NCE. A drug is an NCE if the FDA has not previously approved any other new drug containing the same active moiety, which is the molecule or ion responsible for the action of the drug substance. During the exclusivity period, the FDA may not accept for review an abbreviated new drug application, or ANDA, or a 505(b)(2) NDA submitted by another company for another version of such drug where the applicant does not own or have a legal right of reference to all the data required for approval. However, an application may be submitted after four years if it contains a certification of patent invalidity or non-infringement. The FDCA also provides three years of marketing exclusivity for an NDA, 505(b)(2) NDA or supplement to an existing NDA if new clinical investigations, other than bioavailability studies, that were conducted or sponsored by the applicant are deemed by the FDA to be essential to the approval of the application (for example, for new indications, dosages, or strengths of an existing drug). This three-year exclusivity covers only the conditions associated with the new clinical investigations and does not prohibit the FDA from approving ANDAs for drugs containing the original active agent. Five-year and three-year exclusivity will not delay the submission or tentative approval of a full NDA; however, an applicant submitting a full NDA would be required to conduct or obtain a right of reference to all of the preclinical studies and adequate and well-controlled clinical trials necessary to demonstrate safety and effectiveness.

With respect to Vascepa, we are seeking five-year NCE marketing exclusivity under the FDCA. We believe that the active pharmaceutical ingredient in Vascepa, at least 96% ethyl-EPA, may be considered a new chemical entity, and could therefore be eligible for five-year market exclusivity under the FDCA. The only other omega-3 based product approved by the FDA is Lovaza. We believe the active moiety in Lovaza and the active moiety in Vascepa are different. Lovaza was approved as a lipid-regulating agent by the FDA in 2004 and has been described in its FDA-approved product label as a combination of ethyl esters of omega-3 fatty acids, principally ethyl-EPA and ethyl-DHA. Our belief that Vascepa should be granted NCE exclusivity is based in part on precedent at the FDA for granting NCE status to a previously uncharacterized active moiety, in this case, potentially ethyl-EPA that was part of a previously approved product. It is currently unclear whether the FDA will view the ethyl-EPA in Vascepa as a characterized and previously approved active moiety in Lovaza and deny our request that Vascepa be granted NCE status and the associated period of regulatory exclusivity. The FDA typically makes a determination on NCE exclusivity in connection with, or soon after, an NDA

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approval of a drug for a new indication. The FDA has not yet made its determination regarding NCE exclusivity of Vascepa for the MARINE indication. Separately, we expect to be granted three-year exclusivity of Vascepa for the ANCHOR indication. We cannot assure you that we will be granted our requested periods of exclusivity for the MARINE indication or the ANCHOR indication. If we are not granted NCE exclusivity for the MARINE indication, we expect that we will be granted three-year exclusivity. We also plan to seek regulatory exclusivity for Vascepa in Europe. There can be no assurance that we will be successful in securing marketing approval or regulatory exclusivity in the United States or in Europe.

Pediatric exclusivity is another type of exclusivity in the United States. Pediatric exclusivity, if granted, provides an additional six months to an existing exclusivity or a statutory delay in approval resulting from a patent certification. This six-month exclusivity, which runs from the end of other exclusivity protections or patent delay, may be granted based on the voluntary completion of a pediatric study in accordance with an FDA-issued “Written Request” for such a study. If market exclusivity, as described above, is successful, we will consider pursuing pediatric exclusivity, although there can be no assurance that we will be successful.

Patents, Proprietary Technology, Trade Secrets

Our success depends in part on our ability to obtain and maintain intellectual property protection for our drug candidates, technology and know-how, and to operate without infringing the proprietary rights of others. We seek to protect our chemical compounds and technologies by, among other methods, filing U.S. and foreign patent applications related to our proprietary technology, inventions and improvements that are important to the development of our business. We also rely on trade secrets, know-how, continuing technological innovation and in-licensing opportunities to develop and maintain our proprietary position. We, or our licensors, file patent applications directed to our key drug candidates in an effort to establish intellectual property positions for our product candidates as well as uses of our product candidates in the treatment of diseases. Our patenting strategy encompasses pursuing patents for compositions, formulations, indications/ uses and combinations with other drugs. Amarin is prosecuting multiple patent applications in an effort to protect the intellectual property developed during the Vascepa cardiovascular program.

We believe that patent protection of our technologies, processes and products is important to our future operations. The success of our products may depend, in part, upon our ability to obtain strong patent protection. There can, however, be no assurance that:

Our strategy is to file patent applications where we think it is appropriate to protect and preserve the proprietary technology and inventions considered significant to our business. As of the date of this Annual Report, we have announced that 18 patent applications in the United States have been either issued or allowed and more than 30 additional patent applications are pending in the United States. Of such 18 allowed and issued applications, we currently have two issued U.S. patents directed to a pharmaceutical composition of Vascepa in a capsule that have terms that expire in 2020 and 2030, respectively, one issued U.S. patent covering highly pure EPA which expires in 2021, eight additional U.S. patents covering the use of Vascepa and potentially competitive products in either the MARINE or anticipated ANCHOR indication that have terms that expire in 2030, and have announced Notices of Allowance from the United States Patent and Trademark Office, or USPTO, for seven additional patent applications that have terms that expire in 2030 and are related to the use of Vascepa and potentially competitive products in either the MARINE or anticipated ANCHOR indication. A Notice of Allowance is issued after the USPTO makes a determination that a patent can be granted from an

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application. A Notice of Allowance does not afford patent protection until the underlying patent is issued by the USPTO. No assurance can be given that our issued patents and our pending patents, if and when issued, will prevent competitors from competing with Vascepa.

We have filed and are prosecuting numerous additional patent applications in the United States and internationally that seek to protect the proprietary position of Vascepa. For certain of these patent families, we have filed multiple patent applications. Collectively the patent applications include numerous independent claims and dependent claims. Several of our patent applications contain claims based upon what we believe are unexpected findings from the MARINE and ANCHOR trials. If granted, we believe that many of these resulting patents would expire in 2030 or beyond. However, no assurance can be given that any of our patent applications will be granted or, if they are granted, that they will prevent competitors from competing with Vascepa. Securing patent protection for a product is a complex process involving many legal and factual questions. The patent applications we have filed in the United States and internationally are at varying stages of examination, the timing of which is outside our control. The process to getting a patent granted can be lengthy and claims initially submitted are often modified in order to satisfy the requirements of the patent office. This process includes written and public communication with the patent office. The process can also include direct discussions with the patent examiner. There can be no assurance that the patent office will accept our arguments with respect to any patent application or with respect to any claim therein. The timing of the patent review process is independent of and has no effect on the timing of the FDA’s review of our submissions for regulatory approvals. We cannot predict the timing or results of patent applications. In addition, we may elect to submit, or the patent office may require, additional evidence to support certain of the claims we are pursuing. Providing such additional evidence could result in us incurring additional costs. We cannot be certain what commercial value any granted patent in our patent portfolio will provide to us.

We will also rely upon trade secrets and know-how to retain our competitive position.

We may be dependent in some cases upon third party licensors to pursue filing, prosecution and maintenance of patent rights or applications owned or controlled by those parties. It is possible that third parties will obtain patents or other proprietary rights that might be necessary or useful to us. In cases where third parties are first to invent a particular product or technology, or first to file in the United States, it is possible that those parties will obtain patents that will be sufficiently broad so as to prevent us from utilizing such technology. In addition, we may use unpatented proprietary technology, in which case there would be no assurance that others would not develop similar technology. See Item 1A “Risk Factors—Risks Related to our Intellectual Property and Regulatory Exclusivity—We are dependent on patents, proprietary rights and confidentiality,” and “Risk Factors—Risks Related to our Business—Potential technological changes in our field of business create considerable uncertainty”.

Employees

At December 31, 2012, we had 111 full-time employees employed in marketing, general and administrative and research and development functions. We believe our relations with our employees are good.

Organizational Structure

At December 31, 2012, we had the following subsidiaries:

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Our registered office is located at One New Change, London EC4M 9AF, England. Our principal offices are located at 2 Pembroke House, Upper Pembroke Street 28-32, Dublin 2 Ireland. Our primary offices in the United States are located at 1430 Route 206, Bedminster, NJ 07921, USA. Our telephone number at that location is (908) 719-1315. Our website address is www.amarincorp.com . No information contained on, or accessible through, our website is incorporated by reference into this Annual Report on Form 10-K.

As of the date of this Annual Report on Form 10-K, our principal operating activities were being conducted by Amarin Corporation plc, together with Amarin Pharmaceuticals Ireland Limited and Amarin Pharma Inc., with little to no operating activity being conducted by Amarin Neuroscience Limited, Corsicanto Ltd, or Ester Neurosciences Limited.

On January 9, 2012, Amarin, through its wholly-owned subsidiary Corsicanto Limited, a private limited company incorporated under the laws of Ireland, completed a private placement of $150.0 million in aggregate principal amount of its 3.50% exchangeable senior notes due 2032. The notes are the senior unsecured obligations of Corsicanto and are guaranteed by Amarin Corporation plc. Corsicanto was formed in November 2011 and was subsequently acquired by Amarin in January 2012 for the sole purpose of facilitating this financing transaction.

Financial Information

The financial information required under this Item 1 is incorporated herein by reference to Item 8 of this Annual Report on Form 10-K.

Where You Can Find More Information

You are advised to read this Annual Report on Form 10-K in conjunction with other reports and documents that we file from time to time with the Securities and Exchange Commission, or SEC. You may obtain copies of these reports after the date of this annual report directly from us or from the SEC at the SEC’s Public Reference Room at 100 F Street, N.E. Washington, D.C. 20549. In addition, the SEC maintains information for electronic filers (including Amarin) at its website at www.sec.gov. The public may obtain information regarding the operation of the Public Reference Room by calling the SEC at 1-800-SEC-0330. We make our periodic and current reports, as well as any amendments to such reports, available on our internet website, free of charge, as soon as reasonably practicable after such material is electronically filed with, or furnished to, the SEC.

This Annual Report on Form 10-K contains forward-looking information based on our current expectations. Because our actual results may differ materially from any forward-looking statements that we make or that are made on our behalf, this section includes a discussion of important factors that could affect our actual future results, including, but not limited to, our capital resources, our ability to successfully commercially launch Vascepa, the progress and timing of our clinical programs, the safety and efficacy of our product candidates, risks associated with regulatory filings, the potential clinical benefits and market potential of our product candidates, commercial market estimates, future development efforts, patent protection, effects of healthcare reform, reliance on third parties, and other risks set forth below.

Risks Related to the Commercialization and Development of Vascepa

We are dependent upon the success of Vascepa, which only recently obtained FDA approval and launched commercially in the MARINE indication.

As a result of our reliance on a single product and our primary focus on the U.S. market in the near-term, much of our near-term results and value as a company depends on our ability to execute our commercial strategy for Vascepa in the United States. If commercialization efforts for Vascepa in the MARINE indication or, if

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approved, the ANCHOR indication, are not successful, our business will be materially and adversely affected. Even if we are able to develop additional products from our research and development efforts, the development time cycle for products typically takes several years. This restricts our ability to respond to adverse business conditions for Vascepa. If we are not successful in developing any future product or products, or if there is not adequate demand for Vascepa or the market for such product develops less rapidly than we anticipate, we may not have the ability to effectively shift our resources to the development of alternative products or do so in a timely manner without suffering material adverse effects on our business. As a result, the lack of alternative products we develop could constrain our ability to generate revenues and achieve profitability.

We recently launched Vascepa in the MARINE indication in the United States with our own, newly established sales and marketing teams and distribution channels and we may not be successful.

In late January 2013, we began selling and marketing Vascepa in the United States through our own, newly established sales and marketing teams and through a newly established third-party commercial distribution infrastructure. We hired key personnel in these areas over the last several years and hired and trained a professional sales force in early January 2013. The commercial launch of a new pharmaceutical product is a complex undertaking for a company to manage, and we have no prior experience as a company operating in this area. Factors related to building and managing our own sales and marketing organization that can inhibit our efforts to successfully commercialize Vascepa on our own include:

We also have to compete with other pharmaceutical and life sciences companies to recruit, hire, train and retain sales and marketing personnel, and turnover in our sales force and marketing personnel could negatively affect sales of Vascepa. If we are not successful in our efforts to market and sell Vascepa on our own, market acceptance of Vascepa may be harmed, our anticipated revenues will be materially and negatively impacted, and we may need additional funding or seek a strategic licensing or co-promotion transaction in certain territories as a means of raising additional funds.

Vascepa may fail to achieve the degree of market acceptance by physicians, patients, healthcare payors and others in the medical community necessary for commercial success.

We only recently began marketing and selling Vascepa for use in the MARINE indication in January 2013. Vascepa may fail to gain sufficient market acceptance by physicians, patients, healthcare payors and others in the medical community. If Vascepa does not achieve an adequate level of acceptance, we may not generate significant product revenues and we may not become profitable. The degree of market acceptance of Vascepa for the MARINE indication and any future approved indications will depend on a number of factors, including:

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We may not be able to compete effectively against our competitors’ pharmaceutical products.

The pharmaceutical industry is highly competitive. In attempting to achieve the widespread commercialization of Vascepa, we will face competition to the extent other pharmaceutical companies have on the market, or are able to develop, products for the treatment of similar indications. Potential competitors in this market include companies with greater experience in commercializing pharmaceutical products, and greater resources and name recognition than we have. Furthermore, to the extent we are able to acquire or develop additional marketable products in the future, such products will compete with a variety of other products within the United States or elsewhere, possibly including established drugs and major brand names and also generic versions of these products. Competitive factors, including generic competition, could force us to lower prices or could result in reduced sales. In addition, new products developed by others could emerge as competitors to our future products. Products based on new technologies or new drugs could render our products obsolete or uneconomical.

The success of Vascepa and any of our future products will also depend in large part on the willingness of physicians to prescribe these products to their patients. Vascepa will, and our future products may, compete against products that have achieved broad recognition and acceptance among medical professionals. In order to achieve an acceptable level of prescriptions for Vascepa or any future product, we must be able to meet the needs of both the medical community and end users with respect to cost, efficacy and other factors.

Our potential competitors both in the United States and Europe include large, well-established pharmaceutical companies, specialty pharmaceutical sales and marketing companies, and specialized cardiovascular treatment companies. These companies include GlaxoSmithKline plc, which currently markets Lovaza, a prescription-only omega-3 fatty acid indicated for patients with severe hypertriglyceridemia, and Abbott Laboratories, which currently markets Tricor and Trilipix for the treatment of severe hypertriglyceridemia and mixed dyslipidemia and Niaspan, which is primarily used to raise HDL-C, but is also used to lower triglycerides. In March 2011, Pronova BioPharma Norge AS, now owned by BASF, which owns the patents for Lovaza, entered into an agreement with Apotex Corp. and Apotex Inc. to settle their patent litigation in the United States related to Lovaza. Pursuant to the terms of the settlement agreement, Pronova granted Apotex a license to enter the United States market with a generic version of Lovaza in the first quarter of 2015, or earlier depending on circumstances. We expect Apotex to compete against us as well. Other companies are also seeking to introduce generic versions of Lovaza. These competitors have greater resources than we do, including financial, product development, marketing, personnel and other resources.

In addition, we are aware of other pharmaceutical companies that are developing products that, if approved, would compete with Vascepa. These include a free fatty acid form of omega-3 (comprised of 55% EPA and 20% DHA) which is being developed by Omthera Pharmaceuticals, which in April 2012 announced its top-line Phase 3 clinical trial results and indicated that it plans to submit an NDA during 2013 for the treatment of hypertriglyceridemia. In addition, Acasti Pharma, a subsidiary of Neptune Technologies & Bioresources Inc., announced in late 2012 that it intends to conduct a Phase 3 clinical program to assess the safety and efficacy of its omega-3 prescription drug candidate derived from krill oil for the treatment of hypertriglyceridemia. We believe Resolvyx Pharmaceuticals and Catabasis Pharmaceuticals are also developing potential treatments for hypertriglyceridemia based on omega-3 fatty acids but, to our knowledge, neither has initiated a Phase 2 clinical

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trial of its product. In addition, we are aware that Essentialis, Inc is developing a controlled release diazoxide product for the treatment of hypertriglyceridemia. Essentialis, Inc. has reported that they have completed Phase 2 clinical studies with this product.

Vascepa will also face competition from dietary supplement companies marketing naturally occurring omega-3 fatty acids as nutritional supplements. We cannot be sure physicians will view the FDA-approved prescription-only status, and EPA-only purity of Vascepa as having a superior therapeutic profile to naturally occurring omega-3 fatty acids and dietary supplements.

In addition, other drug companies (commonly known as generic drug companies) may challenge our patents and seek to design products around our issued patent claims and, after a period of FDA-granted regulatory exclusivity gain marketing approval for generic versions of Vascepa or gain marketing approval for branded competitive products based on new clinical studies.

Vascepa is a prescription-only omega-3 fatty acid. Omega-3 fatty acids are also marketed by other companies as non-prescription dietary supplements. As a result, Vascepa would be subject to non-prescription competition and consumer substitution.

Our only current product, Vascepa, is a prescription-only omega-3 fatty acid. Mixtures of omega-3 fatty acids are naturally occurring substances contained in various foods, including fatty fish. Omega-3 fatty acids are also marketed by others as non-prescription dietary supplements. We cannot be sure physicians will view the pharmaceutical grade purity of Vascepa as having a superior therapeutic profile to naturally occurring omega-3 fatty acids and dietary supplements. To the extent the price of Vascepa is significantly higher than the prices of commercially available omega-3 fatty acids marketed by other companies as dietary supplements (through that lack of coverage by insurers or otherwise), physicians may recommend these commercial alternatives instead of writing prescriptions for Vascepa or patients may elect on their own to take commercially available omega-3 fatty acids. Either of these outcomes may adversely impact our results of operations by limiting how we price our product and limiting the revenue we receive from the sale of Vascepa due to reduced market acceptance.

If we are not successful marketing and selling Vascepa on our own, we may need to find collaborative partners to help market and sell the product.

If we are not successful marketing and selling Vascepa on our own, we may need to find collaborative partners to help market and sell the product or otherwise outsource these functions to third parties. Until such time as we choose to, and actually do, complete a strategic transaction with a third party to market and sell Vascepa, if ever, we will continue to market and sell Vascepa on our own. We are actively exploring collaboration opportunities for the continued marketing and sale of Vascepa as we approach the potential approval of Vascepa in the ANCHOR indication, assuming its regulatory approval.

We may not be successful in finding a collaborative partner to help market and sell Vascepa, or may be delayed in doing so, if we determine such a collaborative partner is necessary, in which case we may not receive revenue to the extent that we currently anticipate. We face significant competition in seeking appropriate collaborators, and these collaborations are complex and time-consuming to negotiate and document. We may not be able to negotiate collaborations on acceptable terms, or at all. We likely will have little control over such third parties, and any of them may fail to devote the necessary resources and attention to sell and market our products effectively. If that were to occur, we may have to curtail the continued development of Vascepa for approval for additional indications beyond ANCHOR or increase our planned expenditures and undertake additional development or commercialization activities at our own expense. If we elect to increase our expenditures to fund development or commercialization activities on our own, we will need to obtain additional capital, which may not be available to us on acceptable terms, or at all, or which may not be possible due to our other financing arrangements, including our Purchase and Sale Agreement with Biopharma Secured Debt Fund II Holdings Cayman, L.P., or Biopharma. If we cannot raise sufficient funds, we may not be able to market and sell Vascepa effectively, and generate as much product revenue, as we could under collaboration.

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Our ability to generate increased revenue depends, in part, on FDA approval for the use of Vascepa in the ANCHOR indication in the United States and potentially on other regulatory approvals outside the United States, and we may be delayed in obtaining, or never obtain, such approvals.

The costs involved in obtaining regulatory approvals for pharmaceutical products can be substantial. While we are currently marketing Vascepa for use in the MARINE indication in the United States, our ability to commercialize Vascepa in the ANCHOR indication in the United States or market Vascepa for either indication outside of the United States is dependent upon receiving additional regulatory approvals. Further, while we recently filed a Supplemental New Drug Application, or sNDA, with the FDA for the use of Vascepa in the ANCHOR indication, the acceptance of this submission is dependent on our first reaching, in the opinion of the FDA, substantial enrollment in our REDUCE-IT cardiovascular outcomes study. While we believe that we met this requirement before we submitted our sNDA, the FDA may not agree with us, and thus acceptance of the sNDA could be delayed. Additionally, the FDA could deny approval of our sNDA and require additional testing or data. If the FDA takes any of these actions, they could have a material adverse effect on our operations and financial condition, including our ability to reach profitability.

Even if we obtain additional regulatory approvals for Vascepa, the timing or scope of any approvals may prohibit or reduce our ability to commercialize the product successfully. For example, if the approval process for the ANCHOR indication takes too long, we may miss market opportunities and give other companies the ability to develop competing products or establish market dominance. Additionally, the terms of any approvals, including the approval received from the FDA in July 2012 for the MARINE indication, may prove to not have the scope or breadth needed for us to successfully commercialize Vascepa or become profitable.

Our SPAs with the FDA are not guarantees of FDA approval of Vascepa for the proposed ANCHOR and REDUCE-IT indications.

A Special Protocol Assessment, or SPA, is an evaluation by the FDA of a protocol with the goal of reaching an agreement that the Phase 3 trial protocol design, clinical endpoints, and statistical analyses are acceptable to support regulatory approval of the drug product candidate with respect to effectiveness for the indication studied. The ANCHOR trial was, and the REDUCE-IT trial is, being conducted under an SPA with the FDA. The FDA agreed that, based on the information we submitted to the agency, the design and planned analysis of the ANCHOR trial is adequate to support use of the conducted study as the primary basis for approval with respect to effectiveness. An SPA is generally binding upon the FDA except in limited circumstances, such as if the FDA identifies a substantial scientific issue essential to determining safety or efficacy after the study begins, or if the study sponsor fails to follow the protocol that was agreed upon with the FDA. Even though we have received regulatory approval of Vascepa for the MARINE indication, there is no assurance that the FDA will not identify a scientific issue and deem either or both of the ANCHOR or REDUCE-IT SPAs no longer binding. Moreover, any change to a study protocol after agreement with the FDA is reached can invalidate an SPA. While we amended the protocol for the ANCHOR trial after the initial SPA evaluation was completed, we obtained the FDA’s evaluation of, and agreement to, the amendment. If, for example, the FDA does not consider the applicable SPA to be binding during its review of our regulatory approval applications, or if the FDA determines that we did not follow the SPAs appropriately, the agency could assert that additional studies or data are required to support approval of the application.

The commercial value to us of the MARINE and ANCHOR indications may be smaller than we anticipate.

There can be no assurance as to the adequacy for commercial success of the scope and breadth of the MARINE indication or, if approved, the ANCHOR indication. Even if we obtain marketing approval for additional indications, the FDA may impose restrictions on the product’s conditions for use, distribution or marketing and in some cases may impose ongoing requirements for post-market surveillance, post-approval studies or clinical trials. Also, with regard to the MARINE indication and any other indications for which we may gain approval, the number of actual patients with the condition included in such approved indication may be smaller than we anticipate. If any such approved indication is narrower than we anticipate, the market potential for our product would suffer.

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Our products will be subject to extensive post-approval government regulation.

Once a product candidate receives FDA marketing approval, numerous post-approval requirements apply. Among other things, the holder of an approved NDA is subject to periodic and other monitoring and reporting obligations enforced by the FDA and other regulatory bodies, including obligations to monitor and report adverse events and instances of the failure of a product to meet the specifications in the approved application. Application holders must also submit advertising and other promotional material to regulatory authorities and report on ongoing clinical trials.

With respect to sales and marketing activities, advertising and promotional materials must comply with FDA rules in addition to other applicable federal and local laws in the United States and in other countries. In the United States, the distribution of product samples to physicians must comply with the requirements of the U.S. Prescription Drug Marketing Act. Manufacturing facilities remain subject to FDA inspection and must continue to adhere to the FDA’s current good manufacturing practice requirements, or cGMPs. Application holders must obtain FDA approval for product and manufacturing changes, depending on the nature of the change. We may also be subject, directly or indirectly through our customers and partners, to various fraud and abuse laws, including, without limitation, the U.S. Anti-Kickback Statute, U.S. False Claims Act, and similar state laws, which impact, among other things, our proposed sales, marketing, and scientific/educational grant programs. If we participate in the U.S. Medicaid Drug Rebate Program, the Federal Supply Schedule of the U.S. Department of Veterans Affairs, or other government drug programs, we will be subject to complex laws and regulations regarding reporting and payment obligations. All of these activities are also potentially subject to U.S. federal and state consumer protection and unfair competition laws. Similar requirements exist in many of these areas in other countries.

Depending on the circumstances, failure to meet these post-approval requirements can result in criminal prosecution, fines or other penalties, injunctions, recall or seizure of products, total or partial suspension of production, denial or withdrawal of pre-marketing product approvals, or refusal to allow us to enter into supply contracts, including government contracts. In addition, even if we or our potential partners comply with FDA and other requirements, new information regarding the safety or effectiveness of a product could lead the FDA to modify or withdraw a product approval. Adverse regulatory action, whether pre- or post-approval, can potentially lead to product liability claims and increase our product liability exposure. We or our potential partners must also compete against other products in qualifying for coverage and reimbursement under applicable third party payment and insurance programs.

The FDA and other regulatory agencies strictly regulate the promotional claims that may be made about prescription products. If we are found to have improperly promoted off-label uses, we may become subject to significant fines and other liability.

The FDA and other regulatory agencies strictly regulate the promotional claims that may be made about prescription products. In particular, a product may not be promoted for uses that are not approved by the FDA or such other regulatory agencies as reflected in the product’s approved labeling. Even though we received marketing approval for Vascepa for the MARINE indication only, physicians may nevertheless prescribe Vascepa to their patients in a manner that is inconsistent with the approved label. If we are found to have promoted such off-label uses, we may become subject to significant government fines and other related liability. For example, the Federal government has levied large civil and criminal fines against companies for alleged improper promotion and has enjoined several companies from engaging in off-label promotion. The FDA has also requested that companies enter into consent decrees or permanent injunctions under which specified promotional conduct is changed or curtailed.

In addition, incentives exist under applicable laws that encourage competitors, employees and physicians to report violations of rules governing promotional activities for pharmaceutical products. These incentives could lead to so-called whistleblower lawsuits as part of which such persons seek to collect a portion of moneys allegedly overbilled to government agencies due to, for example, promotion of pharmaceutical products beyond

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labeled claims. These incentives could also lead to suits that we have mischaracterized a competitor’s product in the marketplace and may, as a result, be sued for alleged damages to our competitors. Such lawsuits, whether with or without merit, are typically time-consuming and costly to defend. Such suits may also result in related shareholder lawsuits, which are also costly to defend.

The FDA may disagree with our assertion that our cardiovascular outcomes study, REDUCE-IT, was substantially underway at the time of our sNDA submission, thus delaying FDA review and approval of the ANCHOR indication and costing more than we expect.

Based on our communications with the FDA, to obtain FDA marketing approval of the ANCHOR indication, we believe that we must have a cardiovascular outcomes study, the REDUCE-IT study, substantially underway at the time of the sNDA submission for the ANCHOR indication. In August 2011, we reached an agreement with the FDA on an SPA for the design of the REDUCE-IT cardiovascular outcomes study of Vascepa, and we began dosing patients in December 2011. We submitted our sNDA for approval of the ANCHOR indication in late February 2013 based on our belief that the REDUCE-IT study was substantially underway. The FDA will make the final determination as to whether or not our REDUCE-IT study is sufficiently underway for the FDA to accept the submission of our ANCHOR sNDA.

In the event the FDA does not agree that our REDUCE-IT study is substantially underway, it may reject our submission, repeatedly, until such time as it determines that its study enrollment requirement is met. If we then experience delays in initiating or achieving what the FDA would determine to be substantial enrollment for the REDUCE-IT study or the FDA requires that we enroll still more patients beyond our own expectation of what substantial enrollment entails, our re-submission of an sNDA seeking approval of the ANCHOR indication may be rejected again, or delayed.

Any delay in the acceptance of our submission of the ANCHOR sNDA could have a material adverse effect on our business by delaying the possible approval of Vascepa for use in the ANCHOR indication. In addition, to the extent that we experience delays or need to take actions to prevent delays in the REDUCE-IT cardiovascular outcomes study, the cost of this study will increase. The cost of this study is based on estimates and is not capped.

The REDUCE-IT cardiovascular outcomes trial may fail to show that Vascepa can reduce major cardiovascular events in an at-risk patient population on statin therapy, and the long-term clinical results of Vascepa may not be consistent with the clinical results we observed in our Phase 3 clinical trial, in which case our sales of Vascepa may then suffer.

In accordance with the SPA for our MARINE and ANCHOR trials, efficacy was evaluated in these trials compared to placebo at twelve weeks. No placebo-controlled studies have been conducted regarding the long-term effect of Vascepa on lipids, and no outcomes study has been conducted evaluating Vascepa. The REDUCE-IT study is designed to evaluate the efficacy of Vascepa in reducing major cardiovascular events in an at-risk patient population on statin therapy.

Outcomes studies of certain other lipid modifying therapies have failed to achieve the endpoints of such studies. For example, in September 2012, researchers published in the Journal of the American Medical Association, or JAMA, the results of a retrospective meta-analysis of twenty previously conducted studies regarding the use of omega-3 supplements across various patient populations. This meta-analysis suggested that the use of such supplements was not associated with a lower risk of all-cause death, cardiac death, sudden death, heart attack, or stroke. We believe the results of the JAMA meta-analysis may not be directly applicable to the use of Vascepa over time. For instance, nineteen of the twenty studies included in the JAMA meta-analysis involved the use of omega-3 supplements containing a mixture of EPA and DHA, and most were evaluated at relatively lower doses. Vascepa is comprised of highly-pure ethyl-EPA, and has been approved by the FDA for use in patients with severe hypertriglyceridemia at a dose of 4 grams per day. The only other outcomes study involving the use of a highly-pure formulation of ethyl-EPA, called the Japan EPA Lipid Intervention Study (JELIS), suggested that use of a highly-pure formulation of ethyl-EPA in Japan, when used in conjunction with statins, reduced cardiovascular events by 19% compared to the use of statins alone.

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Although we believe the results of the JAMA meta-analysis and other studies are not directly applicable to the potential long-term clinical experience with Vascepa, there can be no assurance that the endpoints of the REDUCE-IT cardiovascular outcomes study will be achieved or that the lipid modifying effects of Vascepa in REDUCE-IT or any other study of Vascepa will not be subject to variation beyond twelve weeks. If the REDUCE-IT trial fails to achieve its clinical endpoints or if the results of these long-term studies are not consistent with the 12-week clinical results, it could prevent us from expanding the label of any approved product or even call into question the efficacy of any approved product.

We may not be successful in developing or marketing future products if we cannot meet the extensive regulatory requirements of the FDA and other regulatory agencies for quality, safety and efficacy.

The success of our research and development efforts is dependent in part upon our ability, and the ability of our partners or potential partners, to meet regulatory requirements in the jurisdictions where we or our partners or potential partners ultimately intend to sell such products once approved. The development, manufacture and marketing of pharmaceutical products are subject to extensive regulation by governmental authorities in the United States, the European Union, Japan and elsewhere. In the United States, the FDA generally requires pre-clinical testing and clinical trials of each drug to establish its safety and efficacy and extensive pharmaceutical development to ensure its quality before its introduction into the market. Regulatory authorities in other jurisdictions impose similar requirements. The process of obtaining regulatory approvals is lengthy and expensive and the issuance of such approvals is uncertain. The commencement and rate of completion of clinical trials and the timing of obtaining marketing approval from regulatory authorities may be delayed by many factors, including:

Even if we obtain positive results from early stage pre-clinical or clinical trials, we may not achieve the same success in future trials. Clinical trials that we or potential partners conduct may not provide sufficient safety and efficacy data to obtain the requisite regulatory approvals for product candidates. The failure of clinical trials to demonstrate safety and efficacy for our desired indications could harm the development of that product candidate as well as other product candidates, and our business and results of operations would suffer. For example, the efficacy results of our Vascepa Phase 3 clinical trials for the treatment of Huntington’s disease were negative. As a result, we stopped development of that product candidate, revised our clinical strategy and shifted our focus to develop Vascepa for use in the treatment of cardiovascular disease.

Any approvals that are obtained may be limited in scope, may require additional post-approval studies or may require the addition of labeling statements focusing on product safety that could affect the commercial potential for our product candidates. Any of these or similar circumstances could adversely affect our ability to earn revenues from the sale of such products. Even in circumstances where products are approved by a regulatory

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body for sale, the regulatory or legal requirements may change over time, or new safety or efficacy information may be identified concerning a product, which may lead to the withdrawal of a product from the market or similar use restrictions. The discovery of previously unknown problems with a product or in connection with the manufacturer of products may result in restrictions on that product or manufacturer, including withdrawal of the product from the market, which would have a negative impact on our potential revenue stream.

Legislative or regulatory reform of the health care system in the United States and foreign jurisdictions may affect our ability to profitably sell Vascepa.

Our ability to commercialize our future products successfully, alone or with collaborators, will depend in part on the extent to which coverage and reimbursement for the products will be available from government and health administration authorities, private health insurers and other third-party payors. The continuing efforts of the U.S. and foreign governments, insurance companies, managed care organizations and other payors of health care services to contain or reduce health care costs may adversely affect our ability to set prices for our products which we believe are fair, and our ability to generate revenues and achieve and maintain profitability.

Specifically, in both the United States and some foreign jurisdictions, there have been a number of legislative and regulatory proposals to change the health care system in ways that could affect our ability to sell our products profitably. For example, the Patient Protection and Affordable Care Act, as amended by the Health Care and Education Reconciliation Act, or collectively the PPACA, enacted in March 2010, substantially changes the way healthcare is financed by both governmental and private insurers. Among other cost-containment measures, PPACA establishes:

We expect further federal and state proposals and health care reforms to continue to be proposed by legislators, which could limit the prices that can be charged for the products we develop and may limit our commercial opportunity.

The continuing efforts of government and other third-party payors to contain or reduce the costs of health care through various means may limit our commercial opportunity. It will be time consuming and expensive for us to go through the process of seeking coverage and reimbursement from Medicare and private payors. Our products may not be considered cost effective, and government and third-party private health insurance coverage and reimbursement may not be available to patients for any of our future products or sufficient to allow us to sell our products on a competitive and profitable basis. Our results of operations could be adversely affected by PPACA and by other health care reforms that may be enacted or adopted in the future. In addition, increasing emphasis on managed care in the United States will continue to put pressure on the pricing of pharmaceutical products. Cost control initiatives could decrease the price that we or any potential collaborators could receive for any of our future products and could adversely affect our profitability.

In some foreign countries, including major markets in the European Union and Japan, the pricing of prescription pharmaceuticals is subject to governmental control. In these countries, pricing negotiations with governmental authorities can take 6 to 12 months or longer after the receipt of regulatory marketing approval for a product. To obtain reimbursement or pricing approval in some countries, we may be required to conduct a pharmacoeconomic study that compares the cost-effectiveness of Vascepa to other available therapies. Such pharmacoeconomic studies can be costly and the results uncertain. Our business could be harmed if reimbursement of our products is unavailable or limited in scope or amount or if pricing is set at unsatisfactory levels.

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As we evolve from a company primarily involved in research and development to a company also focused on establishing an infrastructure for commercializing Vascepa, we may encounter difficulties in managing our growth and expanding our operations successfully.

We only recently hired and trained a professional sales force of approximately 275 sales representatives and commenced our commercial launch of Vascepa in the MARINE indication in the United States in early January 2013. The process of establishing a commercial infrastructure is difficult, expensive and time-consuming. As our operations expand, we expect that we will need to manage additional relationships with various collaborative partners, suppliers and other third parties. Future growth will impose significant added responsibilities on members of management, including the need to identify, recruit, maintain and integrate additional employees. Our future financial performance and our ability to commercialize Vascepa and to compete effectively will depend, in part, on our ability to manage our future growth effectively. To that end, we must be able to manage our development efforts effectively, and hire, train, integrate and retain additional management, administrative and sales and marketing personnel. We may not be able to accomplish these tasks, and our failure to accomplish any of them could prevent us from successfully growing our company.

Risks Related to our Reliance on Third Parties

Our supply of product for commercial supply and clinical trials is dependent upon relationships with third party manufacturers and key suppliers.

We have no in-house manufacturing capacity and rely on contract manufacturers for our clinical and commercial product supply. We cannot assure you that we will successfully manufacture any product we may develop, either independently or under manufacturing arrangements, if any, with our third party manufacturers. Moreover, if any manufacturer should cease doing business with us or experience delays, shortages of supply or excessive demands on their capacity, we may not be able to obtain adequate quantities of product in a timely manner, or at all.

Any manufacturing problem, natural disaster affecting manufacturing facilities, or the loss of a contract manufacturer could be disruptive to our operations and result in lost sales. Additionally, we will be reliant on third parties to supply the raw materials needed to manufacture our potential products. Any reliance on suppliers may involve several risks, including a potential inability to obtain critical materials and reduced control over production costs, delivery schedules, reliability and quality. Any unanticipated disruption to future contract manufacture caused by problems at suppliers could delay shipment of products, increase our cost of goods sold and result in lost sales. If our suppliers were unable to supply us with adequate supply of ethyl-EPA it would have a material adverse effect on our ability to continue to commercialize Vascepa.

We currently purchase all of our supply of the bulk compound (ethyl-EPA), which constitutes the only active pharmaceutical ingredient, or API, of Vascepa, from a single supplier, Nisshin Pharma, or Nisshin, located in Japan. Nisshin currently obtains its supply of the key raw material to manufacture API from another third party single source of supply. While we have contractual freedom to source the API for Vascepa elsewhere and have entered into supply agreements with additional suppliers who rely on other third party suppliers of the key raw material to manufacture the API for Vascepa, Nisshin is the only supplier approved with our NDA to the FDA.

We intend to purchase increasing amounts of API to support our commercialization of Vascepa. Our strategy is to expand manufacturing capacity and to partially mitigate the risk of reliance on too few suppliers by having multiple API suppliers beyond Nisshin. In December 2012, we announced our submissions of sNDAs to the FDA seeking approval for both Chemport, Inc. and BASF (formerly Equateq Limited) as additional Vascepa API suppliers. Both Chemport and BASF continue to expand their API manufacturing capacity and bring to three the potential number of qualified worldwide supplies of API for Vascepa. Also in December 2012 we announced the addition of an exclusive consortium of companies led by Slanmhor Pharmaceutical, Inc., or Slanmhor, to our planned API global supply chain for Vascepa. Slanmhor was spun-out from Ocean Nutrition Canada, or ONC,

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prior to the May 2012 acquisition of ONC by Royal DSM N.V., a global leader in life sciences and materials sciences. Amarin now has a total of four suppliers for Vascepa API to utilize in supporting the global commercialization of Vascepa, subject to appropriate regulatory approvals. We intend to submit an additional sNDA for Slanhmor after it successfully completes the qualification process.

Expanding manufacturing capacity and qualifying such capacity is difficult and subject to numerous regulations and other operational challenges. The resources of our suppliers are limited and costs associated with projected expansion and qualification can be significant. The resources of our suppliers vary. For example, Chemport, which is one of the API suppliers that we see to qualify, is a privately-held company and their commitment to Vascepa supply has required them to seek additional resources. There can be no assurance that the expansion plans of any of our suppliers will be successful. Our aggregate capacity to produce API is dependent upon the qualification of our API suppliers. Each of our API suppliers has outlined plans for potential further capacity expansion. If no additional API supplier is approved by the FDA, our API supply will be limited to the API we purchase from Nisshin. If our third party manufacturing capacity is not expanded and compliant with application regulatory requirements, we may not be able to supply sufficient quantities of Vascepa to meet anticipated demand. We cannot assure you that we can contract with any future manufacturer on acceptable terms or that any such alternative supplier will not require capital investment from us in order for them to meet our requirements. Alternatively, our purchase of supply may exceed actual demand for Vascepa.

We cannot assure you that we can contract with any future manufacturer on acceptable terms or that any such alternative supplier will not require capital investment from us in order for them to meet our requirements.

We currently rely on two suppliers, Banner and Catalent, for the encapsulation of API for all capsules of Vascepa. While we have contractual freedom to source the API encapsulation for Vascepa elsewhere, Banner and Catalent are the only encapsulators approved by the FDA for encapsulation of API for Vascepa. There can be no guarantee that additional other suppliers with which we have contracted to encapsulate API will be qualified to manufacture the product to our specifications or that these and any future suppliers will have the manufacturing capacity to meeting anticipated demand for Vascepa. We cannot assure you that we can contract with any future manufacturer on acceptable terms or that any such alternative supplier will not require capital investment from us in order for them to meet our requirements.

We do not have sufficient experience with the commercial sale of Vascepa, and such inexperience may cause us to purchase too much or not enough supply to satisfy actual demand, which could have a material adverse effect on our financial results and financial condition.

Our agreements with our suppliers typically include minimum purchase obligations and limited exclusivity provisions. These purchases are generally made on the basis of rolling twelve-month forecasts which in part are binding on us and the balance of which are subject to adjustment by us subject to certain limitations. We have no experience with the commercial sale of Vascepa, and as such expectations regarding expected demand may be wrong. We may not purchase sufficient quantities of Vascepa to meet actual demand or our purchase of supply may exceed actual demand. In either case, such event could have a material adverse effect on our financial results and financial condition.

The manufacture and packaging of pharmaceutical products such as Vascepa are subject to FDA requirements and those of similar foreign regulatory bodies. If we or our third party manufacturers fail to satisfy these requirements, our product development and commercialization efforts may be materially harmed.

The manufacture and packaging of pharmaceutical products, such as Vascepa, are regulated by the FDA and similar foreign regulatory bodies and must be conducted in accordance with the FDA’s current good manufacturing practices and comparable requirements of foreign regulatory bodies. There are a limited number of manufacturers that operate under these current good manufacturing practices regulations who are both capable

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of manufacturing Vascepa and willing to do so. Failure by us or our third party manufacturers to comply with applicable regulations, requirements, or guidelines could result in sanctions being imposed on us, including fines, injunctions, civil penalties, failure of regulatory authorities to grant marketing approval of our products, delays, suspension or withdrawal of approvals, license revocation, seizures or recalls of product, operating restrictions and criminal prosecutions, any of which could significantly and adversely affect our business. For example, our NDA approved by the FDA had only one supplier of API for Vascepa, Nisshin, and Nisshin plans to expand it capacity to supply API to us by further expanding their current facility. If we are not able to manufacture Vascepa to required specifications through Nisshin, we may be delayed in successfully supplying the product to meet anticipated demand and our anticipated future revenues and financial results may be materially adversely affected.

Changes in the manufacturing process or procedure, including a change in the location where the product is manufactured or a change of a third party manufacturer, may require prior FDA review and approval of the manufacturing process and procedures in accordance with the FDA’s current good manufacturing practices, or cGMPs. Any new facility may be subject to a pre-approval inspection by the FDA and would again require us to demonstrate product comparability to the FDA. There are comparable foreign requirements. This review may be costly and time consuming and could delay or prevent the launch of a product. For example, in December 2012, we filed two supplemental NDAs to add new manufacturing facilities for each of BASF and Chemport, and have plans to file another for Slanmhor, to manufacture API for Vascepa. If these third parties cannot establish, to the satisfaction of the FDA, that they are in substantial compliance with cGMPs, and that the products manufactured at the new site meet FDA requirements, we may not be able to manufacture API from that site, our supply of API for Vascepa may be delayed, and our anticipated future revenues and financial results may be materially adversely affected.

Furthermore, the FDA and foreign regulatory agencies require that we be able to consistently produce the active pharmaceutical ingredient and the finished product in commercial quantities and of specified quality on a repeated basis, including proven product stability, and document our ability to do so. This requirement is referred to as process validation. We have not yet completed all of the steps and documentation necessary to validate the process for API manufacturing for Vascepa at any API contract supplier other than Nisshin. Each of our potential API suppliers uses a different method to manufacture API than that used by Nisshin, which has the potential to increase the risk to us that our manufacturers will not meet applicable regulatory requirements. This includes stability testing, measurement of impurities and testing of other product specifications by validated test methods. If the FDA does not consider the result of the process validation or required testing to be satisfactory, the commercial supply of Vascepa may be delayed, or we may not be able to supply sufficient quantities of Vascepa to meet anticipated demand.

The FDA and similar foreign regulatory bodies may also implement new standards, or change their interpretation and enforcement of existing standards and requirements, for manufacture, packaging or testing of products at any time. If we are unable to comply, we may be subject to regulatory, civil actions or penalties which could significantly and adversely affect our business.

During 2013, we are increasing our purchases of API and finished capsules of Vascepa to further expand purchase levels of supply. We may elect to make API purchases from certain of our suppliers after we are satisfied that the material they produce and their facilities are qualified. However, in the event that we make such purchases from other suppliers, we will not be able to use such material for commercial sale until the sNDA for the applicable supplier is approved by the FDA. Similarly, if we are not compliant with other regulations with regard to this intended purchase of supply, our reaching profitability may be delayed.

We rely on third parties to conduct our clinical trials, and those third parties may not perform satisfactorily, including failing to meet established deadlines for the completion of such clinical trials.

Our reliance on third parties for clinical development activities reduces our control over these activities. However, if we sponsor clinical trials, we are responsible for ensuring that each of our clinical trials is conducted

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in accordance with the general investigational plan and protocols for the trial. Moreover, the FDA requires us to comply with standards, commonly referred to as good clinical practices, for conducting, recording, and reporting the results of clinical trials to assure that data and reported results are credible and accurate and that the rights, integrity and confidentiality of trial participants are protected. Our reliance on third parties does not relieve us of these responsibilities and requirements. Furthermore, these third parties may also have relationships with other entities, some of which may be our competitors. If these third parties do not successfully carry out their contractual duties or meet expected deadlines, we may be delayed in obtaining regulatory approvals for our product candidates and may be delayed in our efforts to successfully commercialize our product candidates for targeted diseases.

Risks Related to our Intellectual Property and Regulatory Exclusivity

We are dependent on patents, proprietary rights and confidentiality to protect the commercial potential of Vascepa.

Because of the significant time and expense involved in developing new products and obtaining regulatory approvals, it is very important to obtain patent and preserve trade secret protection for new technologies, products and processes. Our ability to successfully implement our business plan will depend in large part on our ability to:

As of the date of this Annual Report, we have announced that 18 patent applications in the United States have been either issued or allowed and more than 30 additional patent applications are pending in the United States. Of such 18 allowed and issued applications, we currently have two issued U.S. patents directed to a pharmaceutical composition of Vascepa in a capsule that have terms that expire in 2020 and 2030, respectively, one issued U.S. patent covering highly pure EPA which expires in 2021, eight additional U.S. patents covering the use of Vascepa and potentially competitive products in either the MARINE or anticipated ANCHOR indication that have terms that expire in 2030, and have announced Notices of Allowance from the United States Patent and Trademark Office, or USPTO, for seven additional patent applications that have terms that expire in 2030 and are related to the use of Vascepa and potentially competitive products in either the MARINE or anticipated ANCHOR indication. A Notice of Allowance is issued after the USPTO makes a determination that a patent can be granted from an application. A Notice of Allowance does not afford patent protection until the underlying patent is issued by the USPTO. No assurance can be given that our issued patents and our pending patents, if and when issued, will prevent competitors from competing with Vascepa.

We are also pursuing patent applications related to Vascepa in multiple jurisdictions outside the United States, including an application for our MARINE method of use patent in Europe for which we received an Intention to Grant letter from the European Patent Office. We may be dependent in some cases upon third party licensors to pursue filing, prosecution and maintenance of patent rights or applications owned or controlled by those parties. It is possible that third parties will obtain patents or other proprietary rights that might be necessary or useful to us. In cases where third parties are first to invent a particular product or technology, or first to file after various provisions of the America Invents Act of 2011 go into effect on March 16, 2013, it is possible that those parties will obtain patents that will be sufficiently broad so as to prevent us from utilizing such technology or commercializing our current and future products.

Although we intend to make reasonable efforts to protect our current and future intellectual property rights and to ensure that any proprietary technology we acquire or develop does not infringe the rights of other parties,

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we may not be able to ascertain the existence of all potentially conflicting claims. Therefore, there is a risk that third parties may make claims of infringement against our current or future products or technologies. In addition, third parties may be able to obtain patents that prevent the sale of our current or future products or require us to obtain a license and pay significant fees or royalties in order to continue selling such products.

We may in the future discover the existence of products that infringe upon patents that we own or that have been licensed to us. If we were to initiate legal proceedings against a third party to stop such an infringement, such proceedings could be costly and time consuming, regardless of the outcome. No assurances can be given that we would prevail, and it is possible that, during such a proceeding, our patent rights could be held to be invalid, unenforceable or both. Although we intend to protect our trade secrets and proprietary know-how through confidentiality agreements with our manufacturers, employees and consultants, we may not be able to prevent parties subject to such confidentiality agreements from breaching these agreements or third parties from independently developing or learning of our trade secrets.

We anticipate that competitors may from time to time oppose our efforts to obtain patent protection for new technologies or to submit patented technologies for regulatory approvals. Competitors may seek to oppose our patent applications to delay the approval process or to challenge our granted patents, even if the opposition or challenge has little or no merit. Patent opposition proceedings and challenges are generally highly technical, time consuming and expensive to pursue. Were we to be subject to one or more patent oppositions or challenges, that effort could consume substantial time and resources, with no assurances of success, even when holding an issued patent.

Our issued patents and our pending patents, if and when issued, may not prevent competitors from competing with Vascepa.

We plan to vigorously defend our rights under issued patents. Other drug companies may challenge the validity, enforceability or both of the our patents and seek to design its products around our issued patent claims and gain marketing approval for generic versions of Vascepa or branded competitive products based on new clinical studies. The pharmaceutical industry is highly competitive and many of our competitors have greater experience and resources than we have. Any such competition could undermine sales, marketing and collaboration efforts for Vascepa, and thus reduce, perhaps materially, the revenue potential for Vascepa.

Even if we are successful in enforcing our issued patents, we may incur substantial costs and divert management’s time and attention in pursuing these proceedings, which could have a material adverse effect on us. Patent litigation is costly and time consuming. We may not have sufficient resources to bring these actions to a successful conclusion.

There can be no assurance that any of our pending patent applications relating to Vascepa or its use will issue as patents.

We have filed and are prosecuting numerous families of patent applications in the United States and internationally with claims designed to protect the proprietary position of Vascepa. For certain of these patent families, we have filed multiple patent applications. Collectively the patent applications include numerous independent claims and dependent claims. Several of our patent applications contain claims that are based upon what we believe are unexpected and favorable findings from the MARINE and ANCHOR trials. If granted, many of the resulting granted patents would expire in 2030 or beyond. However, no assurance can be given that any of our pending patent applications will be granted or, if they grant, that they will prevent competitors from competing with Vascepa.

Securing patent protection for a product is a complex process involving many legal and factual questions. The patent applications we have filed in the United States and internationally are at varying stages of examination, the timing of which is outside our control. The process to getting a patent granted can be lengthy and claims initially submitted are often modified in order to satisfy the requirements of the patent office. This

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process includes written and public communication with the patent office. The process can also include direct discussions with the patent examiner. There can be no assurance that the patent office will accept our arguments with respect to any patent application or with respect to any claim therein. The timing of the patent review process is independent of and has no effect on the timing of the FDA’s review of our NDA or supplemental NDA submissions. We cannot predict the timing or results of any patent application. In addition, we may elect to submit, or the patent office may require, additional evidence to support certain of the claims we are pursuing. Providing such additional evidence could prolong the patent office’s review of our applications and result in us incurring additional costs. We cannot be certain what commercial value any granted patent in our patent estate will provide to us.

If Vascepa is not granted new chemical entity exclusivity protection from the FDA our business may be materially harmed.

Under Sections 505(c)(3)(E)(ii) and 505(j)(5)(F)(ii) of the Food Drug and Cosmetic Act, or FDCA, as amended by the Drug Price Competition and Patent Term Restoration Act of 1984, as amended, or the Hatch-Waxman Amendments, a drug that is granted regulatory approval may be eligible for five years of marketing exclusivity in the United States following regulatory approval if that drug is classified as a new chemical entity, or NCE. A drug can be classified as a NCE if the FDA has not previously approved any other drug containing the same active moiety.

The FDA typically publishes a determination on the marketing exclusivity of recently approved products in a cumulative supplement to its Approved Drug Products with Therapeutic Equivalence Evaluations, also known as the Orange Book, mid-month in the month following the drug’s approval. Vascepa was approved by the FDA in July 2012, but we have not yet been informed of a determination by the FDA on our pending exclusivity request for Vascepa. Since prior to FDA approval of the Vascepa new drug application, we have had an active dialogue with the FDA related to our marketing exclusivity request for Vascepa, which requested NCE status for Vascepa. In recent months, we have repeatedly followed up with the FDA seeking a determination. While we continue to believe our arguments in support of an NCE determination for Vascepa are strong, the FDA may not agree with our arguments. Based on our discussions with the FDA, we have not been told and do not know what determination the FDA will reach regarding the pending exclusivity request for Vascepa or when the FDA will make such determination. Based on our communications with the FDA, we cannot make a reliable prediction as to when the FDA will communicate a determination on the matter. There can be no assurance that Vascepa will be granted NCE exclusivity, or that the FDA will make a determination on the pending exclusivity request in a timely manner.

NCE marketing exclusivity, if granted, would preclude approval during the five-year exclusivity period of certain 505(b)(2) applications or certain abbreviated new drug applications submitted by another company for another version of the drug. However, an application may be submitted after four years if it contains a certification of patent invalidity or non-infringement. In this case, Amarin may be afforded the benefit of a 30-month stay against the launch of such a competitive product that would extend from the end of the five-year exclusivity period, and may also be afforded other extensions under applicable regulations, including a six-month pediatric exclusivity extension or a judicial extension if applicable requirements are met. If we are not able to gain or exploit the period of marketing exclusivity, we may face significant competitive threats to our commercialization of these compounds from other manufacturers, including the manufacturers of generic alternatives. Further, even if Vascepa is considered to be a NCE and we are able to gain five-year marketing exclusivity, another company could challenge that decision to seek to overturn FDA’s determination. Another company could also gain such marketing exclusivity under the provisions of the FDCA, as amended by the Hatch-Waxman Amendments, if such company can, under certain circumstances, complete a human clinical trial process and obtain regulatory approval of its product.

If Vascepa is not granted NCE marketing exclusivity, we expect it will be granted three years of new product exclusivity under the Hatch-Waxman Amendments. Such exclusivity protection would preclude the FDA from approving a marketing application for a duplicate of Vascepa, a product candidate that the FDA views as

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having the same conditions of approval as Vascepa (for example, the same indication and/or other conditions of use), or a 505(b)(2) NDA submitted to the FDA with Vascepa as the reference product, for a period of three years from the date of FDA approval, although the FDA may accept and commence review of such applications during the exclusivity period. Such three-year exclusivity grant would not prevent a company from challenging the validity of our patents at any time. In this case, Amarin may be afforded the benefit of a 30-month stay against the launch of such a competitive product that would extend from the period that Amarin responds to a pending patent challenge, and may also be afforded other extensions under applicable regulations, including a six-month pediatric exclusivity extension or a judicial extension if applicable requirements are met. This three-year form of exclusivity may also not prevent the FDA from approving an NDA that relies only on its own data to support the change or innovation.

Despite the use of confidentiality agreements and/or proprietary rights agreements, which themselves may be of limited effectiveness, it may be difficult for us to protect our trade secrets.

We will also rely upon trade secrets and know-how to help protect our competitive position. We rely on trade secrets to protect technology in cases when we believe patent protection is not appropriate or obtainable. However, trade secrets are difficult to protect. While we require certain of our academic collaborators, contractors and consultants to enter into confidentiality agreements, we may not be able to adequately protect our trade secrets or other proprietary information.

Risks Related to our Business

Potential technological changes in our field of business create considerable uncertainty.

We are engaged in the biopharmaceutical field, which is characterized by extensive research efforts and rapid technological progress. New developments in research are expected to continue at a rapid pace in both industry and academia. We cannot assure you that research and discoveries by others will not render some or all of our programs or product candidates uncompetitive or obsolete. Our business strategy is based in part upon new and unproven technologies to the development of therapeutics to improve cardiovascular health. We cannot assure you that unforeseen problems will not develop with these technologies or applications or that any commercially feasible products will ultimately be developed by us.

We are subject to potential product liability.

Following the commercial launch of Vascepa, we will be subject to the potential risk of product liability claims relating to the manufacturing and marketing of Vascepa. Any person who is injured as a result of using Vascepa may have a product liability claim against us without having to prove that we were at fault.

In addition, we could be subject to product liability claims by persons who took part in clinical trials involving our current or former development stage products. A successful claim brought against us could have a material adverse effect on our business. We cannot guarantee that a product liability claim will not be asserted against us in the future.

We may become subject to liability in connection with the wind-down of our EN101 program.

In 2007, we purchased Ester Neurosciences Limited, an Israeli pharmaceutical company, and its lead product candidate, EN101, an AChE-R mRNA inhibitor for the treatment of myasthenia gravis, or MG, a debilitating neuromuscular disease. In connection with the acquisition, we assumed a license to certain intellectual property assets related to EN101 from the Yissum Research Development Company of The Hebrew University of Jerusalem.

In June 2009, in keeping with our decision to re-focus our efforts on developing improved treatments for cardiovascular disease and cease development of all product candidates outside of our cardiovascular disease

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focus, we amended the terms of our acquisition agreement with the original shareholders of Ester. Under the terms of this amendment, Amarin was released from all research and development diligence obligations contained in the original agreement and was authorized to seek a partner for EN101. The amendment agreement also provided that any future payment obligations payable by us to the former shareholders of Ester would be made only out of income received from potential partners. In connection with this amendment agreement, in August 2009 we issued 1,315,789 ordinary shares to the former Ester shareholders. Under the terms of this amendment agreement, the former Ester shareholders have the option of reacquiring the original share capital of Ester if we are unable to successfully partner EN101.

Following our decision to cease development of EN101, Yissum terminated its license agreement with us. In June 2011, Yissum announced that it had entered into a license agreement with BiolineRX Ltd for the development of EN101 in a different indication, inflammatory bowel disease.

We have received several communications on behalf of the former shareholders of Ester asserting that we are in breach of its amended agreement due to the fact that Yissum terminated its license and we failed to return shares of Ester, and assets relating to EN101, to the shareholders, as was required under certain circumstances under the amended agreement. We do not believe these circumstances constitute a breach of the amended agreement, but there can be no assurance as to the outcome of this dispute.

A change in our tax residence could have a negative effect on our future profitability.

Under current U.K. legislation, a company incorporated in England and Wales, or which is centrally managed and controlled in the U.K., is regarded as resident in the U.K. for taxation purposes. Under current Irish legislation, a company is regarded as resident for tax purposes in Ireland if it is centrally managed and controlled in Ireland, or, in certain circumstances, if it is incorporated in Ireland. Where a company is treated as tax resident under the domestic laws of both the U.K. and Ireland then the provisions of article 4(3) of the Double Tax Convention between the U.K. and Ireland provides that such enterprise shall be treated as resident only in the jurisdiction in which its place of effective management is situated. We have sought to conduct our affairs in such a way so as to be resident only in Ireland for tax purposes by virtue of having our place of effective management situated in Ireland. Trading income of an Irish company is generally taxable at the Irish corporation tax rate of 12.5%. Non-trading income of an Irish company (e.g., interest income, rental income or other passive income), is taxable at a rate of 25%.

However, we cannot assure you that we are or will continue to be resident only in Ireland for tax purposes. It is possible that in the future, whether as a result of a change in law or the practice of any relevant tax authority or as a result of any change in the conduct of our affairs, we could become, or be regarded as having become resident in a jurisdiction other than Ireland. Should we cease to be an Irish tax resident, we may be subject to a charge to Irish capital gains tax on our assets. Similarly, if the tax residency of any of our subsidiaries were to change from their current jurisdiction for any of the reasons listed above, we may be subject to a charge to local capital gains tax charge on the assets.

The loss of key personnel could have an adverse effect on our business.

We are highly dependent upon the efforts of our senior management. The loss of the services of one or more members of senior management could have a material adverse effect on us. As a small company with a streamlined management structure, the departure of any key person could have a significant impact and would be potentially disruptive to our business until such time as a suitable replacement is hired. Furthermore, because of the specialized nature of our business, as our business plan progresses we will be highly dependent upon our ability to attract and retain qualified scientific, technical and key management personnel. As we evolve from a development stage company to a commercial stage company we may experience turnover among members of our senior management team. We may have difficulty identifying and integrating new executives to replace any such losses. There is intense competition for qualified personnel in the areas of our activities. In this environment, we

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may not be able to attract and retain the personnel necessary for the development of our business, particularly if we do not achieve profitability. The failure to recruit key scientific, technical and management personnel would be detrimental to our ability to implement our business plan.

Risks Related to our Financial Position and Capital Requirements

We have a history of losses and anticipate that we will incur continued losses for an indefinite period of time.

We have not been profitable in any of the last five fiscal years. For the fiscal years ended December 31, 2012, 2011, and 2010, we reported losses of approximately $179.2 million, $69.1 million and $249.6 million, respectively, and we had an accumulated deficit at December 31, 2012 of $747.6 million. Substantially all of our operating losses resulted from costs incurred in connection with our research and development programs, from general and administrative costs associated with our operations, and from non-cash losses on changes in the fair value of warrant derivative liabilities. Additionally, as a result of our significant expenses relating to research and development and to commercialization, we expect to continue to incur significant operating losses for an indefinite period, even after we begin to generate revenues from our commercialization of Vascepa. Because of the numerous risks and uncertainties associated with developing and commercializing pharmaceutical products, we are unable to predict the magnitude of these future losses. Our historic losses, combined with expected future losses, have had and will continue to have an adverse effect on our cash resources, shareholders’ deficit and working capital. We expect our research and development expenses to be substantial for both 2013 and 2014 in connection with our REDUCE-IT cardiovascular outcomes study for Vascepa and other activities. In addition, we may incur significant sales, marketing, in-licensing and outsourced manufacturing expenses as we attempt to commercialize Vascepa. Our shift in focus from research and development to commercialization, and the changes in operating costs relating to that shift, will also require us to make changes to our accounting results and procedures, which may have an adverse effect on our reported revenue or profit, if any.

Although we began generating revenue from Vascepa in January 2013, we may never be profitable.

Our ability to become profitable depends upon our ability to generate revenue. In January 2013, we began to generate revenue from the marketing of Vascepa for use in the MARINE indication, but we may not be able to generate sufficient revenue to attain profitability. Our ability to generate profits on sales of Vascepa is subject to the market acceptance and commercial success of Vascepa and our ability to manufacture commercial quantities of Vascepa through third parties at acceptable cost levels, and may also depend upon our ability to enter into one or more strategic collaborations to effectively market and sell Vascepa.

Even though Vascepa has been approved by the FDA for marketing in the United States in the MARINE indication, it may not gain market acceptance or achieve commercial success and it may never be approved for the ANCHOR indication. In addition, we anticipate continuing to incur significant costs associated with commercializing Vascepa. We may not achieve profitability soon after generating product sales, if ever. If we are unable to generate sufficient product revenues, we will not become profitable and may be unable to continue operations without continued funding.

Our historical financial results do not form an accurate basis for assessing our current business.

As a consequence of the many years developing Vascepa for commercialization and the recent commercial launch of Vascepa in the MARINE indication in the United States, our historical financial results do not form an accurate basis upon which investors should base their assessment of our business and prospects. In addition, we expect that our costs will increase substantially as we continue to commercialize Vascepa in the MARINE indication and seek to obtain additional regulatory approval of Vascepa in the ANCHOR indication, including the continuation of the REDUCE-IT cardiovascular outcomes study. Accordingly, our historical financial results reflect a substantially different business from that currently being conducted and from that expected in the future.

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In addition, we have a limited history of obtaining regulatory approval for, and no demonstrated ability to successfully commercialize, a product candidate. Consequently, any predictions about our future performance may not be as accurate as they could be if we had a history of successfully developing and commercializing pharmaceutical products.

Our operating results are unpredictable and may fluctuate. If our operating results are below the expectations of securities analysts or investors, the trading price of our stock could decline.

Our operating results are difficult to predict and will likely fluctuate from quarter to quarter and year to year. Due to the recent approval by the FDA of Vascepa and the lack of historical sales data, Vascepa sales will be difficult to predict from period to period and as a result, you should not rely on Vascepa sales results in any period as being indicative of future performance, and sales of Vascepa may be below the expectation of securities analysts or investors in the future. We believe that our quarterly and annual results of operations may be affected by a variety of factors, including:

We will require substantial additional resources to fund our operations. If we cannot find additional capital resources, we will have difficulty in operating as a going concern and growing our business.

We currently operate with limited resources. At December 31, 2012, we had cash and cash equivalents of approximately $260.2 million. We believe that our current resources will be sufficient to fund our projected operations for at least the next twelve months, which projected operations contemplate not only working capital and general corporate needs but also the recent commercial launch of Vascepa and the advancement of the REDUCE-IT cardiovascular outcomes study.

In order to fund our commercialization plans, in particular to fully support the launch, marketing and sale of Vascepa in the ANCHOR indication, we will likely need to enter into a strategic collaboration or raise additional capital. We will also need additional capital to fully complete our REDUCE-IT cardiovascular outcomes trial.

Our future capital requirements will depend on many factors, including:

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If adequate funds are not available to us in amounts or on terms acceptable to us or on a timely basis, or at all, and we do not enter into a collaboration agreement to help support the commercialization of Vascepa, our commercialization efforts for Vascepa may suffer materially, and we may need to delay the advancement of the REDUCE-IT cardiovascular outcomes trial.

Continued negative economic conditions would likely have a negative impact on our ability to obtain financing on acceptable terms.

While we may seek additional funding through public or private financings, we may not be able to obtain financing on acceptable terms, or at all. There can be no assurance that we will be able to access equity or credit markets in order to finance our current operations or expand development programs for Vascepa, or that there will not be a further deterioration in financial markets and confidence in economies. We may also have to scale back or further restructure our operations. If we are unable to obtain additional funding on a timely basis, we may be required to curtail or terminate some or all of our research or development programs or our commercialization strategies.

Raising additional capital may cause dilution to our existing shareholders, restrict our operations or require us to relinquish rights.

To the extent we are permitted under our Purchase and Sale Agreement with Biopharma, we may seek additional capital through a combination of private and public equity offerings, debt financings and collaboration, strategic and licensing arrangements. To the extent that we raise additional capital through the sale of equity or convertible debt securities, your ownership interest will be diluted, and the terms may include liquidation or other preferences that adversely affect your rights as a shareholder.

As of December 31, 2012, there were warrants outstanding for the purchase of up to 9,936,826 American Depository Shares, or ADSs, each representing one of our ordinary shares, with a weighted average exercise price of $1.44 per share. We may issue additional warrants to purchase ADSs or ordinary shares in connection with any future financing we may conduct. In addition, on January 9, 2012, we issued $150 million in aggregate principal amount of 3.50% exchangeable senior notes due 2032, or the notes. The notes are exchangeable under certain circumstances into cash, our ADS, or a combination of cash and ADS, at our election, with a current exchange rate of 113.4752 ADS per $1,000 principal amount of notes. Although we intend to settle these notes in cash, if we elected physical settlement, the notes would initially be exchangeable into 17,021,280 ADS.

Debt financing, if available, may involve agreements that include covenants limiting or restricting our ability to take specific actions such as incurring additional debt, making capital expenditures or declaring dividends. If we raise additional funds through collaboration, strategic alliance and licensing arrangements with third parties, we may have to relinquish valuable rights to our technologies, Vascepa or product candidates beyond the rights we have already relinquised, or grant licenses on terms that are not favorable to us.

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Potential business combinations or other strategic transactions may disrupt our business or divert management’s attention.

On a regular basis, we explore potential business combination transactions, including an acquisition of us by a third party, exclusive licenses of Vascepa or other strategic transactions or collaborations with third parties. The consummation and performance of any such future transactions or collaborations will involve risks, such as:

As a result of these risks, we may not be able to achieve the expected benefits of any such transaction or collaboration or deliver the value thereof to our shareholders. If we are unsuccessful in consummating any such transaction or collaboration, we may be required to reevaluate our business only after we have incurred substantial expenses and devoted significant management time and resources.

Risks Related to Ownership of our ADSs and Common Shares

The price of our ADSs and common shares may be volatile.

The stock market has from time to time experienced significant price and volume fluctuations that may be unrelated to the operating performance of particular companies. In addition, the market prices of the securities of many pharmaceutical and medical technology companies have been especially volatile in the past, and this trend is expected to continue in the future.

As of February 20, 2013 we had 150,371,881 common shares outstanding. As of February 20, 2013 there were 149,991,187 shares held as ADSs and 380,694 held as common shares (which are not held in the form of ADSs). In our October 2009 private placement we issued 66.4 million ADSs and warrants to purchase an additional 33.2 million ADSs. There is a risk that there may not be sufficient liquidity in the market to accommodate significant increases in selling activity or the sale of a large block of our securities. Our ADSs have historically had limited trading volume, which may also result in volatility. If any of our large investors, such as the participants in our October 2009 private placement, seek to sell substantial amounts of our ADSs, particularly if these sales are in a rapid or disorderly manner, or other investors perceive that these sales could occur, the market price of our ADSs could decrease significantly.

The market price of our ADSs and common shares may also be affected by factors such as:

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Actual or potential sales of our common shares by our employees, including members of our senior management team, pursuant to pre-arranged stock trading plans could cause our stock price to fall or prevent it from increasing for numerous reasons, and actual or potential sales by such persons could be viewed negatively by other investors.

In accordance with the guidelines specified under Rule 10b5-1 of the Securities and Exchange Act of 1934 and our policies regarding stock transactions, a number of our directors and employees, including members of our senior management team, have adopted and may continue to adopt pre-arranged stock trading plans to sell a portion of our common stock. Generally, sales under such plans by members of our senior management team and directors require public filings. Actual or potential sales of our ADSs by such persons could cause the price of our ADSs to fall or prevent it from increasing for numerous reasons. For example, a substantial amount of our ADSs becoming available (or being perceived to become available) for sale in the public market could cause the market price of our ADSs to fall or prevent it from increasing. Also, actual or potential sales by such persons could be viewed negatively by other investors.

Failure to meet our obligations under our Purchase and Sale Agreement with Biopharma could adversely affect our financial results and liquidity.

Pursuant to our December 2012 Purchase and Sale Agreement with Biopharma, we are obligated to make payments to Biopharma based on the amount of our net product sales of Vascepa and any future products based on ethyl-EPA, or covered products, subject to certain quarterly caps.

Pursuant to this agreement, we may not, among other things: (i) incur indebtedness greater than a specified amount, which we refer to as the Indebtedness Covenant; (ii) pay a dividend or other cash distribution, unless we have cash and cash equivalents in excess of a specified amount after such payment; (iii) amend or restate our memorandum and articles of association unless such amendments or restatements do not affect Biopharma’s interests under the transaction; (iv) encumber any of the collateral securing our performance under the agreement; and (v) abandon certain patent rights, in each case without the consent of Biopharma.

Upon a transaction resulting in a change of control of Amarin, as defined in the agreement, Biopharma will be automatically entitled to receive any amounts not previously paid, up to our maximum repayment obligation. As defined in the agreement, “change of control” includes, among other things, (i) a greater than 50 percent change in the ownership of Amarin, (ii) a sale or disposition of any collateral securing our debt with Biopharma and (iii) , unless Biopharma has been paid a certain amount under the indebtedness, the licensing of Vascepa to a third party for sale in the United States. The acceleration of the payment obligation in the event of a change of control transaction may make us less attractive to potential acquirers, and the payment of such funds out of our available cash or acquisition proceeds would reduce acquisition proceeds for our stockholders.

To secure our obligations under the agreement, we granted Biopharma a security interest in our rights in patents, trademarks, trade names, domain names, copyrights, know-how and regulatory approvals related to the covered products, all books and records relating to the foregoing and all proceeds of the foregoing, which we refer to as the collateral. If we (i) fail to deliver a payment when due and do not remedy that failure within specific notice period, (ii) fail to maintain a first-priority perfected security interest in the collateral in the United States and do not remedy that failure after receiving notice of such failure or (iii) become subject to an event of bankruptcy, then Biopharma may attempt to collect the maximum amount payable by us under this agreement (after deducting any payments we have already made).

There can be no assurance that we will not breach the covenants or other terms of, or that an event of default will not occur under, this agreement and, if a breach or event of default occurs, there can be no assurance that we will be able to cure the breach within the time permitted. Any failure to pay our obligations when due, any breach or default of our covenants or other obligations, or any other event that causes an acceleration of payment at a time when we do not have sufficient resources to meet these obligations, could have a material adverse effect on our business, results of operations, financial condition and future viability.

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Our existing indebtedness could adversely affect our financial condition.

Our existing indebtedness, which we entered into in January 2012, consists of $150.0 million in aggregate principal amount of 3.50% exchangeable senior notes due 2032, with provisions for the notes to be called on or after January 19, 2017. Our indebtedness and the related annual debt service requirements may adversely impact our business, operations and financial condition in the future. For example, they could:

The accounting method for convertible debt securities that may be settled in cash, such as our notes, could have a material effect on our reported financial results.

Under the FASB Accounting Standards Codification, or ASC, we may be required to separately account for the liability and equity components of the convertible debt instruments (such as the notes) that may be settled entirely or partially in cash upon conversion in a manner that reflects the issuer’s economic interest cost. The effect of ASC on the accounting for our outstanding convertible notes may be that the equity component is required to be included in the additional paid-in capital section of stockholders’ equity on our consolidated balance sheets and the value of the equity component would be treated as original issue discount for purposes of accounting for the debt component of the notes. As a result, we may be required to record non-cash interest expense as a result of the amortization of the discounted carrying value of the notes to their face amount over the term of the notes. We may be required to report higher interest expense in our financial results because ASC may require interest to include both the current period’s amortization of the debt discount and the instrument’s coupon interest, which could adversely affect our reported or future financial results and the trading price of our ADSs.

Servicing our debt may require a significant amount of cash, and we may not have sufficient cash flow from our business to provide the funds sufficient to pay our substantial debt.

Our ability to make scheduled payments of the principal of, to pay interest on or to refinance our indebtedness, including the notes, depends on our future performance, which is subject to economic, financial, competitive and other factors beyond our control. Our business may not continue to generate cash flow from operations in the future sufficient to service our debt and make necessary capital expenditures. If we are unable to generate such cash flow, we may be required to adopt one or more alternatives, such as selling assets, restructuring debt or obtaining additional equity capital on terms that may be onerous or highly dilutive. Our ability to refinance our indebtedness will depend on the capital markets and our financial condition at such time. We may not be able to engage in any of these activities or engage in these activities on desirable terms, which could result in a default on our debt obligations, including the notes, and have a material adverse effect on the trading price of our ADSs.

We may be able to incur substantial additional debt in the future, subject to the restrictions contained in our future debt instruments, if any, which would intensify the risks discussed above.

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We may be a passive foreign investment company, or PFIC, which would result in adverse U.S. tax consequences to U.S. investors.

Amarin Corporation plc and certain of our subsidiaries may be classified as “passive foreign investment companies,” or PFICs, for U.S. federal income tax purposes. The tests for determining PFIC status for a taxable year depend upon the relative values of certain categories of assets and the relative amounts of certain kinds of income. The application of these factors depends upon our financial results, which are beyond our ability to predict or control, and which may be subject to legal and factual uncertainties.

While we cannot provide any assurance that we are, are not, or will or will not be, a PFIC now or in the future, we believe it prudent to assume that we were classified as a PFIC in 2012.

If we are a PFIC, U.S. holders of notes, ordinary shares or ADSs would be subject to adverse U.S. federal income tax consequences, such as ineligibility for any preferred tax rates on capital gains or on actual or deemed dividends, interest charges on certain taxes treated as deferred, and additional reporting requirements under U.S. federal income tax laws and regulations. Whether or not U.S. holders of our ADSs make a timely “QEF election” or “mark-to-market election” may affect the U.S. federal income tax consequences to U.S. holders with respect to the acquisition, ownership and disposition of Amarin ADSs and any distributions such U.S. Holders may receive. A QEF election and other elections that may mitigate the effect of our being classified as a PFIC are unavailable with respect to the notes. Investors should consult their own tax advisors regarding all aspects of the application of the PFIC rules to the notes, ordinary shares and ADSs.

The conditional exchange feature of the notes, if triggered, may adversely affect our financial condition and operating results.

In the event the conditional exchange feature of the notes is triggered, holders of notes will be entitled to exchange the notes at any time during specified periods at their option. If one or more holders elect to exchange their notes, unless we elect to satisfy its exchange obligation by delivering solely the ADSs (other than cash in lieu of any fractional ADS), we would be required to settle a portion or all of its exchange obligation through the payment of cash, which could adversely affect our liquidity. In addition, even if holders do not elect to exchange their notes, we could be required under applicable accounting rules to reclassify all or a portion of the outstanding principal of the notes as a current rather than long-term liability, which would result in a material reduction of our net working capital.

The fundamental change repurchase feature of the notes may delay or prevent an otherwise beneficial takeover attempt of us.

The indenture governing the notes will require us to repurchase the notes for cash upon the occurrence of a fundamental change of Amarin and, in certain circumstances, to increase the exchange rate for a holder that exchanges its notes in connection with a make-whole fundamental change. A takeover of us may trigger the requirement that we purchase the notes and/or increase the exchange rate, which could make it more costly for a potential acquirer to engage in a combinatory transaction with us. Such additional costs may have the effect of delaying or preventing a takeover of us that would otherwise be beneficial to investors.

We do not intend to pay cash dividends on the ordinary shares in the foreseeable future.

We have never paid dividends on ordinary shares and do not anticipate paying any cash dividends on the ordinary shares in the foreseeable future. Under English law, any payment of dividends would be subject to relevant legislation and our Articles of Association, which requires that all dividends must be approved by our Board of Directors and, in some cases, our shareholders, and may only be paid from our distributable profits available for the purpose, determined on an unconsolidated basis.

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The rights of our shareholders may differ from the rights typically offered to shareholders of a U.S. corporation.

We are incorporated under English law. The rights of holders of ordinary shares and, therefore, certain of the rights of holders of ADSs, are governed by English law, including the provisions of the Companies Act 2006, and by our Articles of Association. These rights differ in certain respects from the rights of shareholders in typical U.S. corporations. The principal differences include the following:

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We may in the future be subject to the UK Takeover Code which we do not believe is binding on our company at the present time. Nevertheless, the UK Takeover Code could apply to our company under certain circumstances in the future.

We may in the future be subject to the UK City Code on Takeovers and Mergers which we do not believe is binding on our company at the present time.

In the United Kingdom, takeover offers and certain other transactions in respect of certain public companies are regulated by the UK City Code on Takeovers and Mergers, or the Takeover Code, which is administered by the Takeover Panel. Currently, the Takeover Code applies to public companies which have their registered offices in the United Kingdom, the Channel Islands or the Isle of Man if their securities are admitted to trading on a regulated market in the United Kingdom or on a stock exchange in the Channel Islands or the Isle of Man. The Takeover Code also applies to public companies which have their registered office in the United Kingdom, the Channel Islands or the Isle of Man notwithstanding that their securities are not admitted to trading on one of the markets mentioned above, if the Takeover Panel considers that the company has its place of central management and control in the UK, the Channel Islands or the Isle of Man, or the so-called residency test. We do not believe that our company has its place of central management and control in the UK, the Channel Islands or the Isle of Man and we therefore do not believe that the Takeover Code currently applies to us.

In July 2012, the Takeover Panel published three public consultation papers setting out proposed amendments to the Takeover Code, which include a proposal to eliminate the residency test described above. If this proposal is adopted, we could become subject to the Takeover Code since our registered office is in the United Kingdom.

In summary, the Takeover Code sets out binding rules that provide a framework within which takeovers are required to be conducted and this approach differs from the typical U.S. approach which permits the incumbent board greater flexibility to act in a manner it believes is in the best interests of shareholders. The Takeover Code is designed principally to ensure that shareholders in an offeree company are treated fairly, that they are not denied an opportunity to decide on the merits of a takeover and that they are each afforded equivalent treatment by an offeror.

One of the rules of the Takeover Code requires that if an offeror (and persons acting in concert with it) were to acquire interests in our ordinary shares representing 30% or more of the voting rights of all our ordinary shares, the offeror (and, depending upon the circumstances, persons acting in concert with it) would be required (except with the consent of the Takeover Panel) to make a cash offer for the outstanding ordinary shares at a price not less than the highest price paid for any interest in the ordinary shares by the offeror (or persons acting in concert with it) during the 12 months prior to the announcement of that offer. A similar obligation to make such a mandatory offer would also arise on the acquisition of an interest in our ordinary shares by a person holding (together with persons acting in concert with it) an interest representing between 30% and 50% of the voting rights of all our ordinary shares.

If we become subject to the Takeover Code, we will be subject to greater controls in relation to the conduct of any takeover offer for our ordinary shares and this may affect the willingness of potential acquirers to proceed with a takeover offer that would otherwise be beneficial to investors. In addition, if we become subject to the Takeover Code, our board of directors would be less able to exercise its judgment over the conduct of any proposed takeover than it would if the Takeover Code did not apply.

U.S. shareholders may not be able to enforce civil liabilities against us.

We are incorporated under the laws of England and Wales, and our subsidiaries are incorporated in various jurisdictions, including foreign jurisdictions. A number of the officers and directors of each of our subsidiaries are non-residents of the United States, and all or a substantial portion of the assets of such persons are located outside the United States. As a result, it may not be possible for investors to effect service of process within the United States upon such persons or to enforce against them judgments obtained in U.S. courts predicated upon

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the civil liability provisions of the federal securities laws of the United States. We have been advised by our English solicitors that there is doubt as to the enforceability in England in original actions, or in actions for enforcement of judgments of U.S. courts, of civil liabilities to the extent predicated upon the federal securities laws of the United States.

Our directors, management and affiliated investment funds exercise significant control over our company, which will limit your ability to influence corporate matters.

As of February 20, 2013 our executive officers, directors and affiliated investment funds collectively controlled approximately 10.17% of our outstanding ordinary shares, excluding any shares subject to ADSs that such persons may have the right to acquire upon exercise of outstanding options or warrants. As a result, these shareholders, if they act together, will be able to influence our management and affairs and all matters requiring shareholder approval, including the election of directors and approval of significant corporate transactions.

In addition, we entered into an agreement with various participants in the October 2009 private placement under which investment funds affiliated with Orbimed Advisors LLC, Sofinnova Ventures and Abingworth LLP have the ability to designate persons for Amarin to nominate to its Board of Directors and the other participants have given these investments funds a proxy to vote their securities in favor of these nominees. We have a continuing obligation to nominate one (1) designee of investment funds affiliated with Sofinnova Ventures to its Board of Directors for so long as such funds beneficially own at least fifty percent (50%) of the ADSs they purchased in the October 2009 private placement. Dr. James I. Healy was designated by investment funds affiliated with Sofinnova Ventures pursuant to this arrangement. In addition, we have agreed to nominate one (1) designee of investment funds affiliated with Abingworth LLP to its Board of Directors for so long as such funds beneficially own at least five percent (5%) of our outstanding voting securities. Dr. Joseph Anderson was designated by investment funds affiliated with Abingworth LLP under this arrangement. This concentration of ownership and the above-described arrangement may have the effect of delaying or preventing a change in control of our company that other shareholders may desire and might negatively affect the market price of the ADSs.

U.S. holders of the ADSs or ordinary shares may be subject to U.S. income taxation at ordinary income tax rates on undistributed earnings and profits.

There is a risk that we will be classified as a controlled foreign corporation, or CFC, for U.S. federal income tax purposes. If we are classified as a CFC, any ADS holder or shareholder that is a U.S. person that owns directly, indirectly or by attribution, 10% or more of the voting power of our outstanding shares may be subject to U.S. income taxation at ordinary income tax rates on all or a portion of our undistributed earnings and profits attributable to “subpart F income.” Such 10% holder may also be taxable at ordinary income tax rates on any gain realized on a sale of ordinary shares or ADS, to the extent of our current and accumulated earnings and profits attributable to such shares. The CFC rules are complex and U.S. Holders of the ordinary shares or ADSs are urged to consult their own tax advisors regarding the possible application of the CFC rules to them in their particular circumstances.

None.

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The following table lists the location, use and ownership interest of our principal properties as of December 31, 2012:

Effective July 1, 2011, we leased 9,747 square feet of office space in Bedminster, NJ. The lease, as amended, terminates on June 30, 2014, and may also be terminated with six months prior notice. On December 6, 2011 we leased an additional 2,142 square feet of space in the same location. On December 15, 2012 we leased an additional 2,601 square feet of space in the same location.

Effective November 1, 2011, we leased 320 square feet of office space in Dublin, Ireland. The lease terminates on October 31, 2013 and may be renewed annually.

Commencing on November 28, 2011, we leased 4,327 square feet of office space in Groton, CT. The lease terminates on January 31, 2015 and may be extended for one three year term.

Our lease for office space in Ely, Cambridgeshire expires in November 2014. The ground floor space has been sublet through the end of the lease term. On August 27, 2002 the lease for the first floor space was assigned to a third party. Amarin however, remains ultimately responsible for the lease through the end of the lease term.

We believe our existing facilities are adequate for our current needs and that additional space will be available in the future on commercially reasonable terms as needed.

In the ordinary course of business, we are from time to time involved in lawsuits, claims, investigations, proceedings, and threats of litigation relating to intellectual property, commercial arrangements and other matters. While the outcome of these proceedings and claims cannot be predicted with certainty, as of December 31, 2012, we are not a party to any legal or arbitration proceedings that may have, or have had in the recent past, significant effects on our financial position or profitability. No governmental proceedings are pending or, to our knowledge, contemplated against us. We are not a party to any material proceedings in which any director, member of senior management or affiliate of ours is either a party adverse to us or our subsidiaries or has a material interest adverse to us or our subsidiaries.

Not applicable.

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PART II

Market Information

The following table sets forth the high and low prices for our ADSs in each of the quarters over the past two fiscal years, as quoted on the NASDAQ Global Market.

Shareholders

As of January 31, 2013, there were approximately 390 holders of record of our ordinary shares. Because many ordinary shares are held by brokers nominees, we are unable to estimate the total number of shareholders represented by these record holders. Our depositary, Citibank, N.A., constitutes a single record holder of our ordinary shares.

Dividends

We have never paid dividends on common shares and do not anticipate paying any cash dividends on the common shares in the foreseeable future. Under English law, any payment of dividends would be subject to relevant legislation and our Articles of Association, which requires that all dividends must be approved by our Board of Directors and, in some cases, our stockholders, and may only be paid from our distributable profits available for the purpose, determined on an unconsolidated basis.

Under our Purchase and Sale Agreement with Biopharma, we are restricted from paying a dividend on our common shares, unless we have cash and cash equivalents in excess of a specified amount after such payment.

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Performance Graph—3 Year

The following performance graph and related information shall not be deemed “soliciting material” or to be “filed” with the Securities and Exchange Commission, nor shall such information be incorporated by reference into any future filing under the Securities Act of 1933 or Securities Exchange Act of 1934, each as amended, except to the extent that we specifically incorporate it by reference into such filing.

In the opinion of the Board of Directors, the indices below are the most appropriate indices against which the total shareholder return of Amarin should be measured. The NASDAQ Bio Index has been selected because it is an index of U.S. quoted biotechnology and pharmaceutical companies.

Source: NASDAQ—Whole Market index and Bio index. The NASDAQ Market index has been used to compare the shareholder return for all companies listed on the NASDAQ Stock Market. The NASDAQ Bio index has been used to give a comparison of the shareholder returns from biotechnology and pharmaceutical companies listed on the NASDAQ Stock Market.

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Performance Graph—5 Year

The following performance graph and related information shall not be deemed “soliciting material” or to be “filed” with the Securities and Exchange Commission, nor shall such information be incorporated by reference into any future filing under the Securities Act of 1933 or Securities Exchange Act of 1934, each as amended, except to the extent that we specifically incorporate it by reference into such filing.

The following graph compares the cumulative 5-year return provided to stockholders of Amarin’s ADSs 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 ADSs and in each of the indexes on December 31, 2007 and its relative performance is tracked through December 31, 2012.

Information about Our Equity Compensation Plans

Information regarding our equity compensation plans is incorporated by reference in Item 12 of Part III of this annual report on Form 10-K.

UNITED KINGDOM TAXATION

Capital Gains

If you are not resident or ordinarily resident in the United Kingdom (“UK”) for UK tax purposes, you will not be liable for UK tax on capital gains realized or accrued on the sale or other disposition of common shares or ADSs unless the common shares or ADSs are held in connection with your trade carried on in the UK through a branch or agency and the common shares or ADSs are or have been used, held or acquired for the purposes of such trade or such branch or agency.

An individual holder of common shares or ADSs who ceases to be resident or ordinarily resident in the UK for UK tax purposes for a period of less than 5 years and who disposes of common shares or ADSs during that period may also be liable on returning to the UK for UK capital gains tax despite the fact that the individual may not be resident or ordinarily resident in the UK at the time of the disposal.

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Inheritance Tax

If you are an individual domiciled in the United States and are not a national of the UK for the purposes of the Inheritance and Gift Tax Treaty 1978 between the United States and the UK, any common shares or ADSs beneficially owned by you will not generally be subject to UK inheritance tax on your death or on a gift made by you during your lifetime, provided that any applicable United States federal gift or estate tax liability is paid, except where the common share or ADS is part of the business property of your UK permanent establishment.

Where the common shares or ADSs have been placed in trust by a settlor who, at the time of the settlement, was domiciled in the United States and not a national of the UK, the common shares or ADSs will not generally be subject to UK inheritance tax.

Stamp Duty and Stamp Duty Reserve Tax

Transfer of ADSs

No UK stamp duty will be payable on an instrument transferring an ADS or on a written agreement to transfer an ADS provided that the instrument of transfer or the agreement to transfer is executed and remains at all times outside the UK. Where these conditions are not met, the transfer of, or agreement to transfer, an ADS could, depending on the circumstances, attract a charge to ad valorem stamp duty at the rate of 0.5% of the value of the consideration.

No stamp duty reserve tax will be payable in respect of an agreement to transfer an ADS, whether made in or outside the UK.

Issue and Transfer of Common Shares

The issue of common shares by Amarin will not give rise to a charge to UK stamp duty or stamp duty reserve tax.

Transfers of common shares, as opposed to ADSs, will attract ad valorem stamp duty at the rate of 0.5% of the amount or value of the consideration. A charge to stamp duty reserve tax, at the rate of 0.5% of the amount or value of the consideration, will arise on an agreement to transfer common shares. The stamp duty reserve tax is payable on the seventh day of the month following the month in which the charge arises. Where an instrument of transfer is executed and duly stamped before the expiry of a period of six years beginning with the date of that agreement, any stamp duty reserve tax that has not been paid ceases to be payable.

Taxation of Dividends

Under UK law, there is no withholding tax on dividends.

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The selected financial data set forth below as of and for the years ending December 31, 2012, 2011, 2010, 2009 and 2008 have been derived from the audited consolidated financial statements of Amarin, included elsewhere in this Annual Report on Form 10-K. This data should be read in conjunction with our audited consolidated financial statements and related notes which are included elsewhere in this Annual Report on Form 10-K, and “Management’s Discussion and Analysis of Financial Condition and Results of Operations” included in Item 7 below. Historical results are not necessarily indicative of operating results to be expected in the future.

On January 18, 2008, our common shares were consolidated on a 1-for-10 basis whereby ten common shares of £0.05 each became one common share of £0.5. Unless otherwise specified, all shares and share related information have been adjusted to give effect to this 1-for-10 common share consolidation.

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This Annual Report on Form 10-K contains forward-looking statements concerning future events and performance of the Company. When used in this report, the words “may,” “would,” “should,” “could,” “expects,” “aims,” “plans,” “anticipates,” “believes,” “estimates,” “predicts,” “projects,” “potential,” or “continue” or the negative of these terms or other comparable terminology are included to identify forward-looking statements. These statements include but are not limited to statements regarding our ability to successfully launch Vascepa in the United States for use in the MARINE indication, the progress and timing of our clinical programs, the potential for, and timing of, regulatory approval of additional indications for Vascepa and the next steps we may take thereto; the safety and efficacy of our product candidates; the goals of our development activities; the scope of our intellectual property protection; estimates of the potential markets for our product candidates; estimates of the capacity of manufacturing and other facilities to support our products, our operating and growth strategies, our sales and marketing strategies, our industry, our projected cash needs, liquidity and capital resources and our expected future revenues, operations and expenditures. These forward-looking statements are based on our current expectations and assumptions and many factors could cause our actual results to differ materially from those indicated in these forward-looking statements. You should review carefully the factors identified in this report in Item 1A, “Risk Factors”. We disclaim any intent to update or announce revisions to any forward-looking statements to reflect actual events or developments, except as required by law. Except as otherwise indicated herein, all dates referred to in this report represent periods or dates fixed with reference to our fiscal year ended December 31.

Overview

We are a biopharmaceutical company focused on the commercialization and development of therapeutics to improve cardiovascular health. On July 26, 2012, we received approval from the U.S. Food and Drug Administration, or FDA, to market and sell our lead product Vascepa^® (icosapent ethyl) capsules (formerly known as AMR101) as an adjunct to diet to reduce triglyceride, or TG, levels in adult patients with severe (TG ³500mg/dL) hypertriglyceridemia, which we sometimes refer to as the MARINE indication. Triglycerides are fats in the blood. On January 28, 2013, we commenced our commercial launch of Vascepa in the United States for the MARINE indication.

We are also developing Vascepa for the treatment of patients with high (TG ³ 200 mg/dL and <500 mg/dL) triglyceride levels who are also on statin therapy for elevated low-density lipoprotein cholesterol, or LDL-C, levels which we refer to as mixed dyslipidemia. We refer to this second proposed indication for Vascepa as the ANCHOR indication. In late February 2013, we submitted an sNDA for the ANCHOR indication with the FDA. If our sNDA is accepted by the FDA, assuming a ten-month FDA review period, we expect the FDA to assign a PDUFA action date which is not later than the end of 2013.

In December 2011, we announced commencement of patient dosing in our cardiovascular outcomes study of Vascepa, titled REDUCE-IT (Reduction of Cardiovascular Events with EPA – Intervention Trial), which is designed to evaluate the efficacy of Vascepa in reducing major cardiovascular events in a high risk patient population on statin therapy. Based on communications with the FDA, we believe that we are required to be “substantially underway” with a cardiovascular outcomes study at the time of the submission of our sNDA seeking approval of the ANCHOR indication. We believe that we achieved this requirement prior to submitting the sNDA. However, there can be no assurance that the FDA will agree with our assessment or that they will accept our sNDA for the ANCHOR indication. We do not believe the final results of the REDUCE-IT study will be required for FDA approval of Vascepa for the ANCHOR indication.

Hypertriglyceridemia refers to a condition in which patients have high levels of triglycerides in the bloodstream. It is estimated that over 40 million adults in the United States have elevated triglyceride levels >200mg/dL and approximately 4.0 million people in the United States have severely high (TG ³500mg/dL) triglyceride levels, commonly known as very high triglyceride levels. According to The American Heart Association Scientific Statement on Triglycerides and Cardiovascular Disease (2011),

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triglycerides also provide important information as a marker associated with the risk for heart disease and stroke, especially when an individual also has low high-density lipoprotein, or HDL-C (often referred to as “good” cholesterol), and elevated levels of LDL-C (often referred to as “bad” cholesterol). Guidelines for the management of very high triglyceride levels suggest that reducing triglyceride levels is the primary goal in patients to reduce the risk of acute pancreatitis. The effect of Vascepa on cardiovascular mortality and morbidity, or the risk for pancreatitis,in patients with hypertriglyceridemia has not been determined.

The potential efficacy and safety of Vascepa was studied in two Phase 3 clinical trials, the MARINE trial and the ANCHOR trial. At a daily dose of 4 grams of Vascepa, the dose at which Vascepa is FDA-approved, these trials showed favorable clinical results in their respective patient populations in reducing triglyceride levels without increasing LDL-C levels in the MARINE trial and with a statistically significant decrease in LDL-C levels in the ANCHOR trial. These trials also showed favorable results, particularly with the 4-gram dose of Vascepa, in other important lipid and inflammation biomarkers, including apolipoprotein B (apo B), non-high-density lipoprotein cholesterol (non-HDL-C), total-cholesterol (TC), very low-density lipoprotein cholesterol, (VLDL-C), lipoprotein-associated phospholipase A2 (Lp-PLA2), and high sensitivity C-reactive protein (hs-CRP). In these trials, the most commonly reported adverse reaction (incidence >2% and greater than placebo) in Vascepa treated patients was arthralgia (joint pain) (2.3% for Vascepa vs. 1.0% for placebo).

Commercialization Strategy

Vascepa became commercially available in the United States by prescription in January 2013 when we commenced sales and shipments to our network of U.S.-based wholesalers. On January 28, 2013, we commenced our full commercial launch of Vascepa in the United States for use in the MARINE indication. In preparation for our commercial launch, we recently hired and trained a direct sales force of approximately 275 sales representatives. We also employ various marketing and medical affairs personnel to support our commercialization of Vascepa. Our clinical and commercial supply is provided to us under agreements with various third-party suppliers. As of the date of this Annual Report, we have announced that 18 patent applications in the United States have been either issued or allowed and more than 30 additional patent applications are pending in the United States. We are also pursuing patent applications related to Vascepa in multiple jurisdictions outside the United States. These patent applications are part of our strategy to protect the commercial potential of Vascepa, which generally includes obtaining and maintaining intellectual property rights, maintaining trade secrets, seeking regulatory exclusivity and taking advantage of manufacturing barriers to entry.

We believe that our sales and marketing team is well positioned to support the commercialization of Vascepa for the MARINE indication and that a larger sales effort will be required to best support the commercialization of Vascepa for the ANCHOR indication, assuming FDA approval of the ANCHOR indication. To support the continued commercialization of Vascepa, we intend to consider strategic opportunities with larger pharmaceutical companies. From time to time we have held discussions with larger pharmaceutical companies on potential collaborations and other strategic opportunities, and we intend to continue having discussions regarding such opportunities in the future. These strategic opportunities may include licensing or similar transactions, joint ventures, partnerships, strategic alliances, business associations, or a sale of the company. However, we cannot estimate the timing of any such potential strategic transaction, and no assurance can be given that we will enter into any such strategic transaction. Until such time when we enter into such a strategic transaction, if ever, we plan to continue to execute on our plans to market and sell Vascepa on our own.

The U.S. market is currently the primary focus for Vascepa. Opportunities to market and sell Vascepa outside of the United States are also under evaluation.

Prior to commencing our U.S. commercial launch of Vascepa in January 2013, we had no revenue from Vascepa. As of the date of this Annual Report, we do not believe that we can provide a reasonably accurate forecast of Vascepa revenues and we provide no guidance regarding anticipated levels of Vascepa revenues.

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During 2012, we purchased approximately $32 million of Vascepa API of which $21.3 million was capitalized to inventory as of December 31, 2012 and the balance of which was included as a component of research and development expense either because it was received prior to FDA approval of Vascepa for the MARINE indication or because it was used in conjunction with the REDUCE-IT study. The majority of this supply was purchased in the second half of 2012. We anticipate continuing to make substantial purchases of supply during 2013 and beyond. We anticipate that our gross margin from Vascepa sales will be lower in 2013 than in subsequent years due to multiple factors, including API supply pricing at our earliest agreed suppliers being currently higher than supply pricing at more recently agreed suppliers, tiered supply pricing at certain suppliers such that cost of supply purchases are scheduled to decline as volume of purchases increase, special initial stocking discounts provided to wholesalers and pharmacies to encourage them to stock Vascepa in advance of Vascepa’s commercial launch, and rebate cards offered to consumers to reduce the size of their co-payment requirements while we work with payors to migrate Vascepa coverage from “tier-3” to “tier-2” in these payors’ drug pricing systems.

Financial Position

We believe that our cash and cash equivalents balance of $260.2 million at December 31, 2012 is sufficient to fund our projected operations for at least the next twelve months, including commercialization of Vascepa for the MARINE indication, preparations for commercialization of Vascepa for the ANCHOR indication and the advancement of the REDUCE-IT cardiovascular outcomes study. In order to fund our commercialization plans, in particular to fully support the launch, marketing and sale of Vascepa in the ANCHOR indication, we will likely need to enter into a strategic collaboration or raise additional capital.

Critical Accounting Policies and Significant Judgments and Estimates

Our discussion and analysis of our financial condition and results of operations is based on our consolidated financial statements and notes, which have been prepared in accordance with accounting principles generally accepted in the United States. The preparation of these financial statements requires us to make estimates and judgments that affect the reported amounts of assets, liabilities, revenue and expenses. On an ongoing basis, we evaluate our estimates and judgments, including those related to derivative financial liabilities. We base our estimates on historical experience and on various other assumptions that we believe to be reasonable under the circumstances, the results of which form the basis for making judgments about the carrying values of assets and liabilities that are not readily apparent from other sources. Actual results may differ from these estimates under different assumptions or conditions. A summary of our significant accounting policies is contained in Note 2 to our consolidated financial statements included elsewhere in this Annual Report on Form 10-K. We believe the following critical accounting policies affect our more significant judgments and estimates used in the preparation of our consolidated financial statements.

Derivative Financial Liabilities—Derivative financial liabilities on initial recognition are recorded at fair value. They are subsequently held at fair value, with gains and losses arising for changes in fair value recognized in the statement of operations. The fair value of derivative financial liabilities is determined using valuation techniques, typically we use the Black-Scholes option pricing model. We use our judgment to select a variety of methods and make assumptions that are mainly based on market conditions existing at each balance sheet date. Fluctuations in the assumptions used in the valuation model would result in adjustments to the fair value of the warrant derivative laibility reflected on our balance sheet and, therefore, our statement of operations. If we issue shares to discharge the liability, the derivative financial liability is derecognized and common stock and additional paid-in capital are recognized on the issuance of those shares. For options and warrants treated as derivative financial liabilities, at settlement date the carrying value of the options and warrants are transferred to equity. The cash proceeds received from shareholders for additional shares are recorded in common stock and additional paid-in capital. We recorded a financial derivative related the change in control provision associated with our December 2012 debt financing. The fair value of this derivative could fluctuate based on changes the assumptions used in the valuation model.

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Inventory Capitalization—Prior to July 26, 2012, when we received approval from the FDA to market and sell Vascepa in the U.S. for the MARINE indication, Vascepa was considered a product candidate under development. All supply of Vascepa purchased prior to July 26, 2012 was not capitalized and instead charged as a component of research and development expense in the current period. After Vascepa was approved, we began to capitalize inventory purchased from the supplier approved in the NDA. We have three additional supply agreements with BASF, Chemport and Slanmhor, and are working to pursue FDA approval for these suppliers to manufacture Vascepa API. Until an additional API supplier is approved, all Vascepa API purchased from such supplier is included as a component of research and development expense. Upon sNDA approval of these additional suppliers, we plan to capitalize subsequent Vascepa purchases from these suppliers as inventory. Purchases of Vascepa received and expensed before such regulatory approvals will not be subsequently capitalized, and all such purchases will be quarantined and not used for commercial supply until such time as the sNDA for the supplier that produced the API is approved.

Recent Accounting Pronouncements

From time to time, new accounting pronouncements are issued by FASB and are adopted by us as of the specified effective date. Unless otherwise discussed, we believe that the impact of recently issued accounting pronouncements will not have a material impact on consolidated financial position, results of operations, and cash flows, or do not apply to our operations.

Effects of Inflation

We believe the impact of inflation on operations has been minimal during the past three years.

Results of Operations

Comparison of Fiscal Years Ended December 31, 2012 versus December 31, 2011

Revenue. We recorded no revenue in 2012 or 2011.

Research and Development Expense. Research and development expense for the year ended December 31, 2012 was $59.0 million, versus $21.6 million in the prior year period, an increase of $37.4 million, or 173%. Research and development expenses for the years ended December 31, 2012 and 2011 are summarized in the table below:

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In December 2011, we announced that the first patient was dosed in the REDUCE-IT study. During 2012, as planned, we expanded the REDUCE-IT study to include clinical sites in multiple countries, activated clinical sites and enrolled patients. We believe that the patient enrollment phase of the REDUCE-IT study will be the most expensive phase of the study. We anticipate that REDUCE-IT study costs will continue to increase in 2013 as we seek to continue to enroll patients while also continuing our study of patients who were previously enrolled. During 2013, we anticipate incurring expense through our CRO in connection with this trial of between $30 million and $40 million.

The amount charged to research and development expense in 2013 for supply related purchases cannot be reasonably predicted as it depends on the timing of supply shipped to us from BASF, Chemport and Slanmhor and the timing of FDA approval of the these suppliers and their facilities with respect to Vascepa production. We anticipate placing supply purchase orders with these suppliers prior to FDA approval of their facilities provided that we are satisfied that the supply is produced in an appropriate cGMP environment and conforms to our Vascepa product specifications. All such purchases will be quarantined and not used for commercial supply until such time as the sNDA for the applicable supplier that produced the API is approved. After these API suppliers are approved, supply purchases from them will be capitalized as a component of inventory.

We may also increase research and development costs in 2013 related to AMR102. The amount and timing of AMR102 development costs depends on the results of the AMR102 study commenced in 2012, which results have not completed evaluation.

Marketing, General and Administrative Expense. Marketing, general and administrative expense for the year ended December 31, 2012 was $57.8 million, versus $22.6 million in the prior year, an increase of $35.2 million, or 155.8%. Marketing, general and administrative expenses for the years ended December 31, 2012 and 2011 are summarized in the table below:

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We expect marketing, general and administrative costs in 2013 to increase. In late 2012 and early 2013, we hired approximately 275 sales representatives plus district managers to support our January 2013 full launch of Vascepa for the MARINE indication. The cost of this sales team will increase our costs in 2013. In addition, we intend to support the commercialization of Vascepa with expanded medical education programs, various forms of promotion, continued market research and further infrastructure and systems.

Loss on Change in Fair Value of Derivative Liabilities. Loss on change in fair value of derivative liability for the year ended December 31, 2012 was $35.4 million versus $22.7 million in the prior year period. Loss on change in fair value of derivative liability is primarily related to the change in fair value of warrants issued in conjunction with the October 2009 private placement. In October 2009 we issued 36.1 million warrants at an exercise price of $1.50 and recorded a $48.3 million warrant derivative liability, representing the fair value of the warrants issued. As these warrants have been classified as a derivative liability, they are revalued at each reporting period, with changes in fair value recognized in the statement of operations. The fair value of the warrant derivative liability at December 31, 2011 was $123.1 million and we recognized a $22.7 million loss on change in fair value of derivative liability for the period ended December 31, 2011 for these warrants. The fair value of the warrant derivative liability at December 31, 2012 was $54.9 million and we recognized a $35.4 million loss on change in fair value of derivative liability for the period ended December 31, 2012. The decrease in the warrant derivative liability value was due primarily to the exercises of warrants. Upon exercise, the fair value of warrants exercised is remeasured and reclassified from warrant liability to additional paid-in-capital. The fair value of the long term debt redemption feature at December 31, 2012 was 14.6 million. The Company recognized a $0.02 million gain on change in fair value of derivative liability at December 31, 2012. See further discussion of the warrant derivative liability in Note 2 and Note 7 of the Notes to the Consolidated Financial Statements.

Interest Income (Expense), net. Interest income includes interest earned on cash balances. Interest expense includes the amortization of the exchange option related to our exchangeable debt, the amortization of debt discounts and debt obligation coupon interest. During the twelve months ended December 31, 2012, we recognized interest expense of $17.9 million, of which $10.7 million represents amortization of the debt discount, $5.1 million represents contractual coupon interest, $2.1 million represents the amortization of the discount from underwriter discounts and offering costs.

Other (Expense) Income, net. Other income primarily includes unrealized loss due to the fluctuation in the exchange rate of a milestone payment in the amount of $0.5 million between the date that this obligation was incurred on July 26, 2012 and the date that it was paid later in 2012. Also included are gains and losses on other foreign exchange transactions. Other (expense) income for the year ended December 31, 2012 was a net expense of $0.4 million versus $0.01 million in the prior year.

(Provision for) benefit from Income Taxes. Provision for the year ending December 31, 2012 was a $9.1 million provision versus a $2.5 million provision in the prior year. The current provision relates entirely to the United States operations. We are profitable in the United States as a result of intercompany transactions between our United States subsidiary and our other companies. The increase in the 2012 provision for income taxes primarily relates to the exercise of stock options of which the excess benefits related to the option exercises are recorded to additional-paid-in capital.

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Comparison of Fiscal Years Ended December 31, 2011 versus December 31, 2010

Revenue. We recorded no revenue in 2011 or 2010.

Research and Development Expense. Research and development expense for the year ended December 31, 2011 was $21.6 million, versus $28.0 million in the prior year period, a decrease of $6.4 million, or 22.9%. Research and development expenses for the years ended December 31, 2011 and 2010 are summarized in the table below:

General and Administrative Expense. General and administrative expense for the year ended December 31, 2011 was $22.6 million, versus $17.1 million in the prior year, an increase of $5.5 million, or 32.2%. General and administrative expenses for the years ended December 31, 2011 and 2010 are summarized in the table below:

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(Loss) Gain on Change in Fair Value of Derivative Liabilities. (Loss) gain on change in fair value of derivative liability for the year ended December 31, 2011 was expense of $22.7 million versus $205.2 million in the prior year period. (Loss) gain on change in fair value of derivative liability is primarily related to the change in fair value of warrants issued in conjunction with the October 2009 private placement. In October 2009 we issued 36.1 million warrants at an exercise price of $1.50 and recorded a $48.3 million warrant derivative liability, representing the fair value of the warrants issued. As these warrants have been classified as a derivative liability, they are revalued at each reporting period, with changes in fair value recognized in the statement of operations. The fair value of the warrant derivative liability at December 31, 2010 was $230.1 million and we recognized a $205.2 million loss on change in fair value of derivative liability for the period ended December 31, 2010 for these warrants. The fair value of the warrant derivative liability at December 31, 2011 was $123.1 million and we recognized a $22.7 million loss on change in fair value of derivative liability for the period ended December 31, 2011. The decrease in the warrant derivative liability value was due primarily to the exercises of warrants. Upon exercise, the fair value of warrants exercised is remeasured and reclassified from warrant liability to additional paid-in-capital. See further discussion of the warrant derivative liability in Note 2 and Note 7 of the Notes to the Consolidated Financial Statements.

Interest Income (Expense), net. Interest income includes interest earned on cash balances. Interest expense for the year ended December 31, 2011 was $0.001 million versus $0.02 million in the prior year.

Other (Expense) Income, net. Other (expense) income primarily includes gains and losses on foreign exchange transactions. Other (expense) income for the year ended December 31, 2011 was a net expense of $0.01 million versus income of $0.13 million in the prior year.

(Provision for) benefit from Income Taxes. Provision for the year ending December 31, 2011 was a $2.5 million provision versus a $0.5 million benefit in the prior year. The current provision relates entirely to the United States operations. We are profitable in the United States as a result of intercompany transactions between our United States subsidiary and our other companies. The increase in the 2011 provision for income taxes primarily relates to the exercise of stock options of which the excess benefits related to the option exercises are recorded to additional-paid-in capital.

Liquidity and Capital Resources

Our sources of liquidity as of December 31, 2012 include cash and cash equivalents of $260.2 million. Our projected uses of cash include commercialization of Vascepa for the MARINE indication, preparations for commercialization of Vascepa for the ANCHOR indication, the continued funding of the REDUCE-IT cardiovascular outcomes study, working capital and other general corporate activities. Our cash flows from operating, investing and financing activities, as reflected in the consolidated statements of cash flows, are summarized in the following table (in millions):

On December 6, 2012 the Company entered into an agreement with Biopharma Secured Debt Fund II Holdings Cayman LP (“Biopharma”). Under this agreement, the Company granted to Biopharma a security interest in future receivables and all related rights to Vascepa, in exchange for $100 million received at the closing of the agreement which closing occurred in December 2012. The Company has agreed to repay

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Biopharma up to $150 million of future revenue and receivables. The first repayment under the agreement is a repayment of $2.5 million of interest due to Biopharma in November 2013, subject to the limitation described below. Additional quarterly repayments are due thereafter in accordance with the following schedule: $2.5 million of interest in the first quarter of 2014; $8.0 million per quarter in each of the next four quarters, $10.0 million per quarter in each of the next four quarters, $15.0 million per quarter in each of the next four quarters and a final payment of $13.0 million due in May 2017. The quarterly repayments through the third quarter of September 2014 represent interest only. Quarterly payments do not begin to reduce the principal balance until the fourth quarter of 2014. These quarterly payments are subject to a quarterly threshold amount whereby, if a calculated threshold, based on quarterly Vascepa revenues, is not achieved, the quarterly payment payable in that quarter can at our election be reduced and with the reduction carried forward without interest for payment in a future period. Payment of such carried forward amounts are subject to similarly calculated threshold repayment amounts based on Vascepa revenue levels. Except upon a change of control in Amarin, the agreement does not expire until $150 million has been repaid. Under the agreement, upon a change of control, we would be required to pay $140 million, less any previously repaid amount, if the change of control occurs on or before December 31, 2013, or required to repay $150 million, less any previously repaid amount, if the change of control event occurs after December 31, 2013. The Company can prepay after October 1, 2013, an amount equal to $150 million less any previously repaid amount.

On January 9, 2012, Amarin, through its wholly-owned subsidiary Corsicanto Limited, a private limited company incorporated under the laws of Ireland, completed a private placement of $150.0 million in aggregate principal amount of its 3.5% exchangeable senior notes due 2032. The notes are the senior unsecured obligations of Corsicanto Limited and are guaranteed by Amarin. The notes bear interest at a rate of 3.5% per annum, payable semi-annually in arrears on January 15 and July 15 of each year, beginning on July 15, 2012. In July 2012 Amarin made its initial interest payments on the notes in the aggregate amount of $2.7 million. The notes mature on January 15, 2032, unless earlier repurchased, redeemed or exchanged. On or after January 19, 2017, we may elect to redeem for cash all or a portion of the notes for the principal amount of the notes plus accrued and unpaid interest. On each of January 19, 2017, January 19, 2022 and January 19, 2027, the holders of the notes may require that we repurchase in cash the principal amount of the notes plus accrued and unpaid interest. At any time prior to January 15, 2032, upon certain circumstances, which circumstances include our issuing a notice of redemption to the note holders, the price of Amarin shares trading above 130% of the exchange price, or certain other events defined in the note agreement, the holders of the notes may elect to convert the notes. The exchange rate for conversion is 113.4752 ADSs per $1,000 principal amount of the notes (equivalent to an initial exchange price of approximately $8.8125 per ADS), subject to adjustment in certain circumstances, including adjustment if we pay cash dividends. Upon exchange, the notes may be settled, at Amarin’s election, subject to certain conditions, in cash, ADSs or a combination of cash and ADSs. It is the Company’s current intention to settle these obligations in cash.

In January 2011, we sold 13.8 million shares of our common shares, par value £0.50 per share, at a price of $7.60 per share, resulting in net proceeds of approximately $98.7 million after deducting underwriting commissions and expenses payable by us associated with this transaction.

We believe that our cash and cash equivalents balance of $260.2 million at December 31, 2012 is sufficient to fund our projected operations for at least the next twelve months, including commercialization of Vascepa for the MARINE indication, preparations for commercialization of Vascepa for the ANCHOR indication and the advancement of the REDUCE-IT cardiovascular outcomes study. In order to fund our commercialization plans, in particular to fully support the launch, marketing and sale of Vascepa in the ANCHOR indication, we will likely need to enter into a strategic collaboration or raise additional capital.

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Contractual Obligations

The following table summarizes our contractual obligations at December 31, 2012 and the effects such obligations are expected to have on our liquidity and cash flows in future periods (in millions):

Payments Due by Period

We do not enter into financial instruments for trading or speculative purposes.

The above table also does not reflect potential material purchases under the API supply agreements with BASF, Chemport or the consortium led by Slanmhor. These API supply agreements provide access to additional API supply that is incremental to supply from Nisshin Pharma, our existing FDA-approved API supplier. Each of these additional API agreements contemplates a phased capacity expansion plan aimed at creating sufficient capacity to meet anticipated demand for API material for Vascepa following commercial launch. These API suppliers are self-funding these expansion plans with contributions from Amarin. These agreements include requirements for the suppliers to qualify their materials and facilities. We anticipate incurring certain costs associated with the qualification of product produced by these suppliers. These agreements include annual

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purchase levels enabling Amarin to maintain supply exclusivity with each respective supplier, and to prevent potential termination of the agreements. These minimum purchase levels do not contractually begin until the applicable supplemental NDA, or sNDA, for the supplier is approved by the FDA, if ever, and upon the achievement of manufacturing capacity expansion. Accordingly, these amounts are excluded from the above table. The two supply agreements entered into in 2011, the agreements with BASF and Chemport, also include (i) development fees up to a maximum of $0.5 million, (ii) material commitments of up to $5.0 million for initial raw materials, which will be credited against future API purchases, and is refundable to us if a supplier does not successfully develop and qualify the API by a certain date and (iii) a raw material purchase commitment of $1.1 million. Under these agreements, during 2012 we purchased $1.0 million of Vascepa API from Chemport and made advance payments of $3.2 million for API from BASF.

The agreement with the fourth API supplier, when all contingencies are eliminated by the supplier, provides for development fees of up to $2.3 million and a commitment of up to $15.0 million, which will be credited against future API material purchases. Under this agreement, during 2012 we made payments of $1.6 million to Slanhmor related to stability and technical batches and advances on future API purchases.

Concurrent with our supply agreements with Chemport entered into in 2011 for the supply of API materials for Vascepa, we agreed to make a noncontrolling minority share equity investment in the supplier of up to $3.3 million. The Company invested $1.7 million under this agreement in July 2011 and the remaining $1.6 million during 2012. These amounts have been included in other long term assets and accounted for under the cost method at December 31, 2012.

Under the 2004 share repurchase agreement with Laxdale Limited, or Laxdale, upon receipt of marketing approval in the U.S. and/or Europe for the first indication for Vascepa (or first indication of any product containing Amarin Neuroscience intellectual property acquired from Laxdale in 2004), the Company must make an aggregate stock or cash payment to the former shareholders of Laxdale (at the sole option of each of the sellers) of £7.5 million (approximately $12.1 million at December 31, 2012) for each of the two potential marketing approvals. Upon approval of Vascepa by the FDA on July 26, 2012, the Company capitalized this first Laxdale milestone ($11.6 million on July 26, 2012) as a component of other long term assets and recorded an accrued liability payable to the former Laxdale shareholders. This long-term asset will be amortized over the estimated useful life of the intellectual property the Company acquired from Laxdale and the Company recognized amortization expense of $0.3 million during the year ended December 31, 2012. The Company paid $12.1 million in cash in November 2012 in settlement of this liability and recognized a currency exchange loss of $0.5 million.

Also under the Laxdale agreement, upon receipt of a marketing approval in the U.S. or Europe for a further indication of Vascepa (or further indication of any other product using Amarin Neuroscience intellectual property), the Company must make an aggregate stock or cash payment (at the sole option of each of the sellers) of £5 million (approximately $8.1 million at December 31, 2012) for each of the two potential market approvals (i.e. £10 million maximum, or approximately $16.2 million at December 31, 2012).

In addition to the obligations in the table above, we have approximately $0.8 million of liability for uncertain tax positions that have been recorded in long-term liabilities at December 31, 2012. We are not able to reasonably estimate in which future periods these amounts will ultimately be settled.

Off-Balance Sheet Arrangements

We do not have any special purpose entities or other off-balance sheet arrangements.

Shelf Registration Statement

On March 29, 2011, we filed with the SEC a universal shelf registration statement on Form S-3 (Registration No. 333-173132), which provides for the offer, from time to time, of an indeterminate and unlimited amount of: ordinary shares, which may be represented by American Depositary Shares; preference

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shares, which may be represented by American Depositary Shares; senior or subordinated debt securities; warrants to purchase any of these securities; and any combination of these securities, individually or as units. In addition, if we identify any security holder(s) in a prospectus supplement, they may also offer identified securities under this registration statement although we will not receive any of the proceeds from the sale of securities by any of these selling security holders. This universal shelf registration statement was automatically effective upon its filing. The addition of any newly issued equity securities into the market may be dilutive to existing stockholders and new issuances by us or sales by our selling security holders could have an adverse effect on the price of our securities.

We are exposed to market risks, which include changes in interest rates, changes in credit worthiness and liquidity of our marketable securities. We do not use derivative financial instruments in our investment portfolio, and prior to 2013 we entered into no foreign exchange contracts. Our investments meet high credit quality and diversification standards, as specified in our investment policy. At December 31, 2012, we record as a liability the fair value of warrants to purchase 8.1 million shares of our common stock issued to investors. The fair value of this warrant liability is determined using the Black-Scholes option valuation model and is therefore sensitive to changes in the market price and volatility of our common stock among other factors. In the event of a hypothetical 10% increase in the market price of our common shares ($8.90 based on the $8.09 market price of our stock at December 31, 2012) on which the December 31, 2012 valuation was based, the value of the derivative liability would have increased by $6.4 million. Such increase would have been reflected as additional loss on change in fair value of the warrant derivative liability in our statement of operations.

Foreign Currency Exchange Risk. Our results of operations and cash flows are subject to fluctuations due to changes in the Euro, Sterling and Yen. The majority of cash and cash equivalents and the majority of our vendor relationships are denominated in U.S. dollar. We therefore believe that the risk of a significant impact on our operating income from foreign currency fluctuations is not substantial. From time to time, we maintain a small amount of our cash in cash equivalents in Euro and Pound Sterling. We purchase supply from Nisshin in Japanese Yen. As our level of supply purchases from Nisshin have increased, we in 2013 have begun to enter into short-term forward currency pricing contracts to lock-in the exchange rate on a portion of our anticipated purchases denominated in Japanese Yen.

Interest Rate Risk. We believe that we are not exposed to significant interest rate risk through market value fluctuations of balance sheet items (i.e., price risk) or through changes in interest income or expenses (i.e., re-financing or re-investment risk). Interest rate risk mainly arises through interest bearing liabilities and assets. We invest funds not needed for near-term operating expenses in diversified short-term investments, consisting primarily of investment grade securities. As of December 31, 2012, the fair value of our cash and cash equivalents maturing in one year or less was $260.2 million and represented 100% of our cash, cash equivalents and investment portfolio. A hypothetical 50 basis point increase in interest rates would not result in a material decrease or increase in the fair value of our securities due to the general short-term nature of our investment portfolio.

Our consolidated financial statements are annexed to this report beginning on page F-1.

None.

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Evaluation of Disclosure Controls and Procedures

We maintain disclosure controls and procedures that are designed to ensure that information required to be disclosed in the reports that we file or submit under the Securities Exchange Act of 1934, as amended (the “Exchange Act”), is (1) recorded, processed, summarized, and reported within the time periods specified in the SEC’s rules and forms and (2) accumulated and communicated to our management, including our Principal Executive Officer and Principal Financial Officer, to allow timely decisions regarding required disclosure. As of December 31, 2012 (the “Evaluation Date”), our management, with the participation of our Principal Executive Officer and Principal Financial Officer, evaluated the effectiveness of our disclosure controls and procedures (as defined in Rules 13a-15(e) and 15d-15(e) under the Exchange Act). Our 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. Our Principal Executive Officer and Principal Financial Officer have concluded based upon the evaluation described above that, as of the Evaluation Date, our disclosure controls and procedures were effective at the reasonable assurance level.

Management’s Report on Internal Control over Financial Reporting

Our management is responsible for establishing and maintaining adequate internal control over financial reporting for our company. Internal control over financial reporting is defined in Rules 13a-15(f) and 15(d)-15(f) promulgated under the Exchange Act as a process designed by, or under the supervision of, our Principal Executive Officer and Principal Financial Officer and effected by our board of directors, management, and other personnel to provide reasonable assurance regarding the reliability of financial reporting and the preparation of financial statements for external purposes in accordance with generally accepted accounting principles and includes those policies and procedures that:

Because of inherent limitations, internal controls over financial reporting may not prevent or detect misstatements. Projections of any evaluation of effectiveness to future periods are subject to the risks that controls may become inadequate because of changes in conditions or that the degree of compliance with the policies or procedures may deteriorate.

Our management, including our Principal Executive Officer and Principal Financial Officer, has conducted an evaluation of the effectiveness of our internal control over financial reporting as of December 31, 2012. In conducting this evaluation, we used the criteria set forth by the Committee of Sponsoring Organizations of the Treadway Commission (COSO), in Internal Control-Integrated Framework.

Based upon this evaluation and those criteria, management believes that, as of December 31, 2012, our internal controls over financial reporting were effective.

Deloitte and Touche LLP, our independent registered public accounting firm, has audited our consolidated financial statements and the effectiveness of our internal control over financial reporting as of December 31, 2012. This report appears below.

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Changes in Internal Control over Financial Reporting

There were no changes in our internal control over financial reporting during the fourth quarter of 2012 that have materially affected, or are reasonably likely to materially affect, our internal control over financial reporting.

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REPORT OF INDEPENDENT REGISTERED PUBLIC ACCOUNTING FIRM

To the Board of Directors and Stockholders of

Amarin Corporation plc

Dublin, Ireland

We have audited the internal control over financial reporting of Amarin Corporation plc and subsidiaries (the “Company”) as of December 31, 2012, based on criteria established in Internal Control—Integrated Framework issued by the Committee of Sponsoring Organizations of the Treadway Commission. The Company’s management is responsible for maintaining effective internal control over financial reporting and for its assessment of the effectiveness of internal control over financial reporting, included in the Management’s Report on Internal Control over Financial Reporting. Our responsibility is to express an opinion on the Company’s internal control over financial reporting based on our audit.

We conducted our audit in accordance with the standards of the Public Company Accounting Oversight Board (United States). Those standards require that we plan and perform the audit to obtain reasonable assurance about whether effective internal control over financial reporting was maintained in all material respects. Our audit included obtaining an understanding of internal control over financial reporting, assessing the risk that a material weakness exists, testing and evaluating the design and operating effectiveness of internal control based on the assessed risk, and performing such other procedures as we considered necessary in the circumstances. We believe that our audit provides a reasonable basis for our opinion.

A company’s internal control over financial reporting is a process designed by, or under the supervision of, the company’s principal executive and principal financial officers, or persons performing similar functions, and effected by the company’s board of directors, management, and other personnel to provide reasonable assurance regarding the reliability of financial reporting and the preparation of financial statements for external purposes in accordance with generally accepted accounting principles. A company’s internal control over financial reporting includes those policies and procedures that (1) pertain to the maintenance of records that, in reasonable detail, accurately and fairly reflect the transactions and dispositions of the assets of the company; (2) provide reasonable assurance that transactions are recorded as necessary to permit preparation of financial statements in accordance with generally accepted accounting principles, and that receipts and expenditures of the company are being made only in accordance with authorizations of management and directors of the company; and (3) provide reasonable assurance regarding prevention or timely detection of unauthorized acquisition, use, or disposition of the company’s assets that could have a material effect on the financial statements.

Because of the inherent limitations of internal control over financial reporting, including the possibility of collusion or improper management override of controls, material misstatements due to error or fraud may not be prevented or detected on a timely basis. Also, projections of any evaluation of the effectiveness of the internal control over financial reporting to future periods are subject to the risk that the controls may become inadequate because of changes in conditions, or that the degree of compliance with the policies or procedures may deteriorate.

In our opinion, the Company maintained, in all material respects, effective internal control over financial reporting as of December 31, 2012, based on the criteria established in Internal Control—Integrated Framework issued by the Committee of Sponsoring Organizations of the Treadway Commission.

We have also audited, in accordance with the standards of the Public Company Accounting Oversight Board (United States), the consolidated financial statements as of and for the year ended December 31, 2012 of the Company and our report dated February 28, 2013 expressed an unqualified opinion on those financial statements.

/s/ DELOITTE & TOUCHE LLP

Boston, Massachusetts

February 28, 2013

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Entry into Rule 10b5-1 Trading Plans

Our policy governing transactions in our securities by our directors, officers and employees permits our officers, directors and certain other persons to enter into trading plans complying with Rule 10b5-1 under the Securities Exchange Act of 1934, as amended. We have been advised that a number of our directors and employees, including members of our senior management team, and investment funds associated with such persons, have entered into trading plans in accordance with Rule 10b5-1 and our policy governing transactions in our securities. We undertake no obligation to update or revise the information provided herein, including for revision or termination of an established trading plan.

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PART III

The information required by this item will be contained in our definitive proxy statement, which will be filed with the SEC in connection with our 2013 Annual General Meeting of Shareholders. Such information is incorporated herein by reference.

Code of Ethics

Our Board of Directors has adopted a code of business conduct and ethics that applies to our directors, officers and employees. There have been no material modifications to, or waivers from, the provisions of such code. This code is available on the corporate governance section of our website (which is a subsection of the investor relations section of our website) at the following address: www.amarincorp.com. Any waivers from or amendments to the code will be filed with the SEC on Form 8-K. You may also request a printed copy of the code, without charge, by writing to us at Amarin Pharma, Inc., 1430 Route 206, Bedminster, NJ 07921, Attention: Investor Relations.

The information required by this item will be contained in our definitive proxy statement, which will be filed with the SEC in connection with our 2013 Annual General Meeting of Shareholders. Such information is incorporated herein by reference.

The information required by this item will be contained in our definitive proxy statement, which will be filed with the SEC in connection with our 2013 Annual General Meeting of Shareholders. Such information is incorporated herein by reference.

The information required by this item will be contained in our definitive proxy statement, which will be filed with the SEC in connection with our 2013 Annual General Meeting of Shareholders. Such information is incorporated herein by reference.

The information required by this item will be contained in our definitive proxy statement, which will be filed with the SEC in connection with our 2013 Annual General Meeting of Shareholders. Such information is incorporated herein by reference.

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PART IV

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