Amarin Reports Fourth Quarter and Year-End 2013 Financial Results and Provides Update on Operations - Conference Call Set for 4:30 p.m. EST Today - BEDMINSTER, N.J., and

Amarin Reports Fourth Quarter and Year-End 2013 Financial Results

and Provides Update on Operations

- Conference Call Set for 4:30 p.m. EST Today -

BEDMINSTER, N.J., and DUBLIN, Ireland, February 27, 2014 Amarin Corporation plc (Nasdaq: AMRN), a late stage biopharmaceutical company

focused on the commercialization and development of therapeutics to improve cardiovascular health, today announced financial results for the quarter and year ended December 31, 2013, and provided an update on company operations.

Key Amarin milestones since September 30, 2013 include:

Just over one year ago, the culmination of many years of hard work came to fruition as Vascepa was first made

available to physicians and patients in the United States, said John F. Thero, President and Chief Executive Officer of Amarin. 2013 was a year of significant achievement for Amarin as a commercial organization was established and

Vascepa helped to improve patient care options in the treatment of severe hypertriglyceridemia. As we embark on our second year as a commercial organization we stand by our commitment to work toward label expansion for Vascepa to improve treatment

options for patients with mixed dyslipidemia.

Commercialization update

Vascepa is marketed as an

adjunct to diet to reduce triglyceride levels in adult patients with severe (>500 mg/dL) hypertriglyceridemia, the MARINE indication. We began marketing Vascepa in late January 2013. Vascepa labeling reflects a spectrum of favorable

effects on lipid and lipoprotein parameters at 4 g/day, including statistically significant reductions in TG, Apo B, VLDL-C, and non-HDL-C, with no increase in LDL-C, also known as bad cholesterol, and a safety profile that is comparable to placebo.

The most common reported adverse reaction (incidence > 2% and greater than placebo) was arthralgia (2.3% for Vascepa, 1.0% for placebo). With the benefit of this clinical profile, Amarin made significant progress throughout 2013 in multiple areas

of the Vascepa commercialization plan. Vascepa is now available on formulary to over 200 million lives in the United States, including over 100 million in Tier 2 coverage. The conversion of these lives to Tier 2 status has helped enable

Amarin to grow the Vascepa prescriber base to over 16,000 physicians since launch.

Amarin believes that Vascepa sales will continue to grow with the

promotion of the MARINE indication. In late 2013, Amarin shifted its main focus to the approximately 7,000 targeted physicians who are responsible for a significant portion of the prescriptions generated for the leading prescription omega-3 therapy

indicated for the treatment of severe hypertriglyceridemia. In addition to Amarin s direct sales outreach, focus on this important customer segment throughout 2014 will be achieved through multichannel awareness campaigns, including medical

education and promotional educational programs; disease state and other direct personal campaigns; managed care education and presence at key medical association and scientific meetings.

Vascepa additional indication

marketing Vascepa for the MARINE indication, Amarin is vigorously pursuing FDA approval of Vascepa for the ANCHOR indication, a second indication as an adjunct to diet and exercise for adult patients with mixed dyslipidemia who despite optimized

statin therapy have TG levels between 200 and 499 mg/dL. As previously announced, FDA rescinded the ANCHOR SPA agreement and has not yet made a determination on Amarin s supplemental NDA for the ANCHOR indication. Amarin continues to seek

approval of the ANCHOR indication and has taken steps to appeal the FDA s rescission of the SPA. Based on planned discussions with the FDA, Amarin will assess its options with respect to the ANCHOR sNDA and the extent to which Amarin should

continue its other clinical trials, including the ongoing REDUCE-IT outcomes trial.

REDUCE-IT and other Vascepa-related clinical development

Enrollment for the REDUCE-IT outcomes trial of Vascepa continues at over 400 sites spanning 11 countries. Earlier this year enrollment for the

REDUCE-IT trial surpassed 6,500 patients. As previously reported, the mean and median baseline triglyceride levels for patients participating to date in the REDUCE-IT cardiovascular outcomes study is >200 mg/dL. Results of the REDUCE-IT study

will not be available until a specified number of cardiovascular events have been observed. Based on current expectations, unless feedback from pending discussion with the FDA regarding the ANCHOR sNDA results in modification or termination of the

REDUCE-IT study, completion of this blinded study is anticipated in or about 2017. Amarin estimates that over $100 million is required to complete this study. While Amarin remains scientifically committed to continuing the REDUCE-IT study, Amarin

anticipates that the trial may be difficult to complete in its current form without the expected revenues from the previously anticipated ANCHOR indication, as communicated to the FDA.

Amarin reported cash and cash equivalents on-hand of $191.5 million at December 31, 2013.

Net product revenues for the three and twelve months ended December 31, 2013 were $10.1 million and $26.4 million, as compared to no revenues in the

corresponding periods of 2012. In accordance with accounting principles generally accepted in the U.S. (US GAAP), and consistent with previously reported revenue results, until the company has more operating history with the commercialization of

Vascepa, it is recognizing revenue based not on its sales to wholesalers but based on the resale of Vascepa for the purpose of filling prescriptions. For the year ended December 31, 2013, the net value of Vascepa sold to wholesalers was $28.1

million, and, as a result, in addition to $26.4 million in recognized revenue, Amarin recorded deferred revenue of $1.7 million at December 31, 2013. Cash collections from the sale of Vascepa in the quarter ended December 31, 2013 were

approximately $13.2 million for a total of $31.7 million collected from wholesalers since the launch of Vascepa.

Consistent with industry practice, the

net price of Vascepa for the three and twelve months ended December 31, 2013 reflects deductions for costs of Amarin s co-payment rebate card program and customary payor rebates and allowances. The net price also includes adjustments for

other customary amounts as well as the deduction of one-time discounts paid to wholesalers to stock Vascepa in advance of Vascepa s launch in January 2013, which discounted stock was principally sold during the first half of 2013.

Cost of goods sold for the three and twelve months ended December 31, 2013 was $4.1 million and $11.9 million, respectively. Gross margin improved to 59%

in Q4 2013 from 56% in Q3, 48% in Q2 and 45% in Q1, which was primarily driven by lower unit cost API purchases. Average gross margin was 55% for the year ended December 31, 2013. The majority of Vascepa capsules included in cost of goods sold

for the year ended December 31, 2013 included API sourced from a single API supplier. Amarin s purchases of API from this supplier in 2012 and 2013 are at higher cost per kilogram than expected future purchases from this supplier and from

Amarin s other API suppliers due to more favorable economic terms under such supply agreements.

Under U.S. GAAP, Amarin reported a net loss of $15.4

million in the fourth quarter of 2013, or basic and diluted loss per share of $0.09 and $0.27, respectively. This net loss included $0.5 million in non-cash, share-based compensation expense, $2.5 million in non-cash warrant compensation income, and

a $26.7 million non-cash gain on the change in the fair value of derivatives. For the year ended December 31, 2013, Amarin reported a net loss of $166.2 million, or basic and diluted loss per share of $1.03 and $1.28, respectively. This net

loss included $14.7 million in non-cash share-based compensation expense, $3.7 million in non-cash warrant compensation income, and a $47.7 million gain on the change in the fair value of derivatives.

Excluding non-cash gains or losses for share-based compensation, warrant compensation and the change in fair value of derivatives, non-GAAP adjusted net loss

was $44.1 million for the fourth quarter of 2013, or non-GAAP adjusted basic and diluted loss per share of $0.26, as compared to non-GAAP adjusted net loss of $42.0 million, or non-GAAP adjusted basic and diluted loss per share of $0.28 for the same

period in 2012. Adjusted net loss was $203.0 million for the twelve months ended December 31, 2013, or non-GAAP adjusted basic and diluted loss per share of $1.26, as compared to non-GAAP adjusted net loss of $125.5 million, or non-GAAP

adjusted basic and diluted loss per share of $0.87 for the same period in 2012.

Amarin reported cash and cash equivalents decreased in aggregate by $68.7 million from December 31, 2012 as

compared to December 31, 2013. Net cash outflows from operations were $190.3 million for the year ended December 31, 2013. Net cash outflows from operations for the three months ended December 31, 2013 were $33.1 million as compared

to $44.9 million in net cash outflows from operations for the three months ended September 30, 2013, representing a net decrease of $11.8 million. The net cash outflows for the three months ended December 31, 2013 included approximately

$2.7 million in payments for severance and employee benefits associated with a company-wide reduction in force in October 2013. As a result of the headcount reductions and additional anticipated reductions in spend, Amarin expects that it will

experience continued reductions in quarterly net cash outflows from operations with future quarterly cash outflows below the results of the fourth quarter. Amarin estimates that during 2014 operating activities will result in a net use of cash of

less than $80 million.

During the year ended December 31, 2013, net cash outflows included approximately $90.4 million in sales and marketing

related expenses in conjunction with the initial commercial launch of Vascepa, approximately $47.0 million of expenses in support of the REDUCE-IT cardiovascular outcomes study inclusive of clinical trial materials and approximately $25.7 million

for Vascepa API, purchased in conjunction with the buildup of commercial supply. Amarin s estimate of cash flows assumes lower purchases of commercial supply in 2014 based on relatively high inventory balances on hand at the end of 2013.

Amarin s liabilities as of December 31, 2013, excluding the fair value of the non-cash warrant derivative liability, totaled approximately $279.4

million, which includes $149.3 million for the carrying value of exchangeable debt and $87.7 million for the carrying value of the hybrid debt financing that we entered into in December 2012.

As of December 31, 2013, Amarin had approximately 172.7 million American Depository Shares (ADSs) and ordinary shares outstanding as well as

approximately 9.8 million and 9.3 million equivalent shares underlying warrants and stock options, respectively, at average exercise prices of $1.44 and $6.64, respectively, and 0.2 million equivalent shares underlying restricted or

deferred stock units.

Amarin s operational priorities

Amarin s current operational priorities are:

Conference call and webcast information

Amarin will host a conference call at 4:30 p.m. ET (9:30 p.m. UTC/GMT) today, February 27, 2014. The conference call can be

heard live via the investor relations section of the company s website at www.amarincorp.com, or via telephone by dialing 877-407-8033 within the United States or 201-689-8033 from outside the United States. A replay of the call will be

made available for a period of two weeks following the conference call. To hear a replay of the call, dial 877-660-6853 (inside the United States) or 201-612-7415 (outside the United States). A replay of the call will also be available through the

company s website shortly after the call. For both dial-in numbers please use conference ID 13576006.

Use of non-GAAP adjusted financial information

Included in this press release and the conference call referenced above are non-GAAP adjusted financial information as defined by U.S. Securities and Exchange

Commission Regulation G. The GAAP financial measure most directly comparable to each non-GAAP adjusted financial measure used or discussed, and a reconciliation of the differences between each non-GAAP adjusted financial measure and the comparable

GAAP financial measure, are included in this press release after the condensed consolidated financial statements.

Non-GAAP adjusted net loss was derived

by taking GAAP net loss and adjusting it for non-cash gains or losses for share-based compensation, warrant compensation, and change in value of derivatives. Management believes that these non-GAAP adjusted measures provide investors with a better

understanding of the company s historical results from its core business operations. While management believes that these non-GAAP adjusted financial measures provide useful supplemental information to investors regarding the underlying

performance of the company s business operations, investors are reminded to consider these non-GAAP measures in addition to, and not as a substitute for, financial performance measures prepared in accordance with GAAP. Non-GAAP measures have

limitations in that they do not reflect all of the amounts associated with the company s results of operations as determined in accordance with GAAP. In addition, it should be noted that these non-GAAP financial measures may be different from

non-GAAP measures used by other companies, and management may utilize other measures to illustrate performance in the future.

Amarin Corporation plc is a biopharmaceutical company focused on the commercialization and development of therapeutics to improve cardiovascular health.

Amarin s product development program leverages its extensive experience in lipid science and the potential therapeutic benefits of polyunsaturated fatty acids. Vascepa (icosapent ethyl),

Amarin s first FDA approved product, is a patented, ultra pure omega-3 fatty acid product comprising not less than 96% EPA. For more information about Vascepa visit www.vascepa.com. For more information about Amarin visit www.amarincorp.com.

About Vascepa (icosapent ethyl) capsules

Vascepa (icosapent ethyl) capsules, known in scientific literature as AMR101, is a highly

pure-EPA omega-3 prescription product in a 1 gram capsule.

Indications and Usage

Important Safety Information for Vascepa

FULL VASCEPA PRESCRIBING INFORMATION CAN BE FOUND AT WWW.VASCEPA.COM.

Vascepa has been approved for use by the FDA as an adjunct to diet to reduce triglyceride levels in adult patients with severe (>500 mg/dL)

hypertriglyceridemia. Vascepa is under various stages of development for potential use in other indications that have not been approved by the FDA. Nothing in this press release should be construed as marketing the use of Vascepa in any indication

that has not been approved by the FDA.

Forward-looking statements

This press release contains forward-looking statements, including statements about the commercial launch of Vascepa, including the number of total

prescriptions to date and the potential for future growth, expectations for revenue growth, product awareness, receptivity of clinicians to and patient experience with Vascepa; expectations regarding managed care coverage migration from Tier 3 to

Tier 2 and continued growth in Tier 2 coverage; the pricing terms of commercial supply for Vascepa; expectations regarding gross margins and cost of goods sold (COGS); the timing and outcome of FDA decisions regarding Amarin s sNDA for the