Amarin Submits Supplemental New Drug Application (sNDA) to U.S. FDA Seeking New Indication for Vascepa (icosapent ethyl) to Reduce the Risk of Major Adverse Cardiovascular Events Based on Landmark REDUCE-IT Cardiovascula

Amarin Submits Supplemental New Drug Application (sNDA) to U.S. FDA Seeking New Indication for

Vascepa (icosapent ethyl) to Reduce the Risk of Major Adverse Cardiovascular Events Based on Landmark

REDUCE-IT Cardiovascular Outcomes Study

BEDMINSTER, N.J., and DUBLIN, Ireland, March 28, 2019 Amarin Corporation plc (NASDAQ:AMRN), a pharmaceutical company focused on improving

cardiovascular health, today announced that, as planned, it submitted a supplemental new drug application (sNDA) to the U.S. Food and Drug Administration (FDA) seeking an expanded indication for its lead product, Vascepa (icosapent ethyl) capsules, based on the landmark REDUCE-IT cardiovascular outcomes study1, 2. As is typical, while the FDA acknowledged receipt of the sNDA submission, at this stage FDA has not yet communicated to Amarin the intended timing of its review. Unless and until the company

learns otherwise in communications from the FDA, the review timing is typically communicated within 60 to 74 days of the FDA s receipt of an sNDA. Amarin is operating under the assumption that the sNDA will be reviewed on a standard review

clock of ten months resulting in a PDUFA date near the end of January 2020.

This submission is another step forward toward our goal to help address

the risk of cardiovascular disease, said John F. Thero, president and chief executive officer of Amarin. The REDUCE-IT results support that approximately 1 fewer major cardiovascular adverse event

would occur on average for every 6 patients treated with Vascepa for 5 years on top of statin therapy compared to placebo1. This unprecedented result beyond cholesterol management presents an

important new preventative care opportunity for millions of patients.

As is typical for a trial of this size, the electronic sNDA submission

consists of over 5 million pages of information regarding Vascepa, including data from over 35,000 patient years of study in REDUCE-IT. A total events analysis from the

REDUCE-IT study was recently published online in the Journal of the American College of Cardiology1, and the primary results of the REDUCE-IT study were previously published in The New England Journal of Medicine2. In REDUCE-IT, Vascepa

provided a 25% relative risk reduction compared to placebo in the first occurrence of a major adverse CV event (MACE) in the intent-to-treat population consisting of a

composite of cardiovascular death, nonfatal myocardial infarction (MI or heart attack), nonfatal stroke, coronary revascularization (procedures such as stents and by-pass) and unstable angina requiring

hospitalization. For total (first and subsequent) cardiovascular events, Vascepa provided a statistically significant 30% risk reduction compared to placebo in the statin-treated patient population studied in

REDUCE-IT. REDUCE-IT was performed under a Special Protocol Assessment (SPA) with the FDA. In REDUCE-IT, adverse events occurring

with Vascepa use at greater than 5% and greater than placebo were: peripheral edema (6.5% Vascepa versus 5.0%), although there was no increase in the rate of heart failure in Vascepa patients; constipation (5.3% Vascepa versus 3.6%), although

mineral oil, as used as placebo, is known to lower constipation; and atrial fibrillation (5.3% Vascepa versus 3.9%), although there were reductions in rates of cardiac arrest, sudden death and myocardial infarctions observed in Vascepa patients.

More information on safety data associated with REDUCE-IT is provided below.

Amarin has previously expressed that it believes it is likely that there will be an Advisory Committee

(AdCom) meeting organized by the FDA in conjunction with its review of the expanded label for Vascepa sought in its sNDA based on the landmark results of the REDUCE-IT cardiovascular outcomes study and the

very large patient population that Vascepa could potentially address. However, the FDA determination as to whether or not there will be an AdCom has not yet been communicated to Amarin. Typically, the FDA does not communicate such a decision until

it has had the opportunity to substantially review the sNDA.

Amarin Corporation plc. is a rapidly growing, innovative pharmaceutical company focused on developing therapeutics to improve cardiovascular health.

Amarin s product development program leverages its extensive experience in polyunsaturated fatty acids and lipid science. Vascepa (icosapent ethyl) is Amarin s first FDA-approved drug and is

available by prescription in the United States, Lebanon and the United Arab Emirates. Amarin s commercial partners are pursuing additional regulatory approvals for Vascepa in Canada, China and the Middle East. For more information about Amarin,

visit www.amarincorp.com.

8,179-patient cardiovascular outcomes study, was completed in 2018. REDUCE-IT was the first multinational cardiovascular outcomes study that evaluated the effect of

prescription pure EPA therapy as an add-on to statins in patients with high cardiovascular risk who, despite stable statin therapy, had elevated triglyceride levels (at least 135 mg/dL). A large portion of the

male and female patients enrolled in this outcomes study were diagnosed with type 2 diabetes.

More information on the

REDUCE-IT study results can be found at www.amarincorp.com.

About Cardiovascular Disease

Worldwide, cardiovascular disease (CVD) remains the #1 killer of men and women. In the United States CVD leads to one in every three deaths one death

approximately every 38 seconds with annual treatment cost in excess of $500 billion.3, 4

Multiple primary and secondary prevention trials have shown a significant reduction of 25% to 35% in the risk of cardiovascular

events with statin therapy, leaving significant persistent residual risk despite the achievement of target LDL-C levels.5

Beyond the cardiovascular risk associated with LDL-C, genetic, epidemiologic, clinical and real-world data suggest

that patients with elevated triglycerides (TG) (fats in the blood), and TG-rich lipoproteins, are at increased risk for cardiovascular disease. 6, 7, 8, 9

About Vascepa (icosapent ethyl) Capsules

Vascepa (icosapent ethyl) capsules are a single-molecule prescription product consisting of the omega-3 acid commonly

known as EPA in ethyl-ester form. Vascepa is not fish oil, but is derived from fish through a stringent and complex FDA-regulated manufacturing process designed to effectively eliminate impurities and isolate

and protect the single molecule active ingredient from degradation. Vascepa, known in scientific literature as AMR101, has been designated a new chemical entity by the FDA. Amarin has been issued multiple patents internationally based on the unique

clinical profile of Vascepa, including the drug s ability to lower triglyceride levels in relevant patient populations without raising LDL-cholesterol levels.

Indication and Usage Based on Current FDA-Approved Label (not including

Important Safety Information for Vascepa Based on Current FDA-Approved Label (not including REDUCE-IT results) (Includes Data from Two 12-Week Studies (n=622) (MARINE and ANCHOR) of Patients

with Triglycerides Values of 200 to 2000 mg/dL)

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

Important Safety Information for Vascepa based on REDUCE-IT, as previously reported in The

New England Journal of Medicine2 publication of the primary results of the REDUCE-IT study:

Vascepa has been approved for use by the United States Food and Drug Administration (FDA) as an adjunct to diet to reduce triglyceride levels in adult

patients with severe ( 500 mg/dL) hypertriglyceridemia. FDA has not reviewed and opined on a supplemental new drug application related to REDUCE-IT. FDA has not

reviewed the information herein or determined whether to approve Vascepa for use to reduce the risk of MACE. Nothing in this press release should be construed as promoting the use of Vascepa in any indication that has not been approved by the FDA.

Important Cautionary Information About These Data

Further REDUCE-IT data assessment and data release could yield additional useful information to inform greater

understanding of the trial outcome. Further detailed data assessment by Amarin and regulatory authorities will continue and take several months to complete and record. The final evaluation of the totality of the efficacy and safety data

from REDUCE-IT may include some or all of the following, as well as other considerations: new information affecting the degree of treatment benefit on studied endpoints; study conduct and data robustness,

quality, integrity and consistency; additional safety data considerations and risk/benefit considerations; consideration of REDUCE-IT results in the context of other clinical studies.

Recurrent event analyses for the total primary endpoint events and for the total key secondary endpoint in REDUCE-IT

as published in the Journal of the American College of Cardiology1 were conducted using a series of statistical models. These analyses were tertiary or exploratory endpoints; most of

the models used were prespecified and one was post hoc. Each recurrent event statistical model has inherent strengths and weaknesses, with no single model considered definitive or outperforming the other models, and this is an evolving field of

science. Nonetheless, results from the total primary and total key

secondary endpoint events analyses are consistent across the various recurrent event statistical models and are also consistent with the original primary and secondary endpoint results. Together,

the REDUCE-IT recurrent event analyses and the original primary and key secondary endpoint analyses support the robustness of the clinical benefit of Vascepa therapy in reducing cardiovascular risk.

Forward-Looking Statements

This press release contains

forward-looking statements, including expectations regarding FDA review and related timelines, that REDUCE-IT results could lead to a new treatment paradigm in the patient population studied and present an

important new preventative care opportunity for millions of patients. These forward-looking statements are not promises or guarantees and involve substantial risks and uncertainties. In addition, Amarin s ability to effectively commercialize

Vascepa will depend in part on its ability to continue to effectively finance its business, efforts of third parties, its ability to gain regulatory approvals, create market demand for Vascepa through education, marketing and sales activities, to

achieve market acceptance of Vascepa, to receive adequate levels of reimbursement from third-party payers, to develop and maintain a consistent source of commercial supply at a competitive price, to comply with legal and regulatory requirements in

connection with the sale and promotion of Vascepa and to maintain patent protection for Vascepa. Among the factors that could cause actual results to differ materially from those described or projected herein include the following: uncertainties

associated generally with research and development, clinical trials and related regulatory approvals; the risk that sales may not meet expectations and related cost may increase beyond expectations; the risk that patents may not be upheld in patent

litigation and applications may not result in issued patents sufficient to protect the Vascepa franchise. A further list and description of these risks, uncertainties and other risks associated with an investment in Amarin can be found in

Amarin s filings with the U.S. Securities and Exchange Commission, including its most recent annual report on Form 10-K. Existing and prospective investors are cautioned not to place undue reliance on

these forward-looking statements, which speak only as of the date hereof. Amarin undertakes no obligation to update or revise the information contained in this press release, whether as a result of new information, future events or circumstances or

Availability of Other Information About Amarin

Investors and others should note that Amarin communicates with its investors and the public using the company website (www.amarincorp.com), the investor

relations website (investor.amarincorp.com), including but not limited to investor presentations and investor FAQs, Securities and Exchange Commission filings, press releases, public conference calls and webcasts. The information that Amarin posts

on these channels and websites could be deemed to be material information. As a result, Amarin encourages investors, the media, and others interested in Amarin to review the information that is posted on these channels, including the investor

relations website, on a regular basis. This list of channels may be updated from time to time on Amarin s investor relations website and may include social media channels. The contents of Amarin s website or these channels, or any other

website that may be accessed from its website or these channels, shall not be deemed incorporated by reference in any filing under the Securities Act of 1933.

Amarin Contact Information

Investor Relations and Corporate Communications

In U.S.: +1 (908) 719-1315

investor.relations@amarincorp.com (investor inquiries)

PR@amarincorp.com (media inquiries)

In U.S.: +1 (646) 378-2992