AMARIN CORP PLC\UK — Director's Dealing 2011

Jan 3, 2011

SEC Form 3 — Initial Statement of Beneficial Ownership

Issuer: AMARIN CORP PLC\UK (AMRN)
CIK: 0000897448
Period of Report: 2011-01-01

Reporting Person: ORBIMED ADVISORS LLC (Director, 10% Owner)
Reporting Person: OrbiMed Capital GP III LLC (Director, 10% Owner)
Reporting Person: ISALY SAMUEL D (Director, 10% Owner)

Holdings (Non-Derivative)

Security	Shares	Ownership
Ordinary Shares	7295000	Indirect

Holdings (Derivative)

Security	Exercise Price	Expiration	Underlying	Shares	Ownership
Warrant	$1.50	2014-10-16	Ordinary Shares (3500000)		Indirect
Stock Options (right to buy)	$1.03	2020-02-10	Ordinary Shares (120000)		Indirect

Footnotes

F1: The Ordinary Shares may be represented by American Depositary Shares, each of which currently represents one Ordinary Share.

F2: The Ordinary Shares (the "Shares") reported herein as indirectly beneficially owned by OrbiMed Capital GP III LLC ("Capital"), OrbiMed Advisors LLC ("Advisors") and Samuel D. Isaly ("Isaly") are directly owned by OrbiMed Private Investments III, LP ("OPI III") and OrbiMed Associates III, LP ("Associates"). Of this amount, OPI III and Associates hold 7,226,100 and 68,900 Shares, respectively. Capital, pursuant to its authority as the general partner of OPI III, may be considered to hold indirectly 7,226,100 Shares and Advisors, pursuant to its authority as the managing member of Capital and general partner of Associates, may be considered to hold indirectly 7,295,000 Shares.

F3: Capital is the sole general partner of OPI III. Advisors, a registered adviser under the Investment Advisers Act of 1940, as amended, is the sole managing member of Capital and the sole general partner of Associates. Isaly, a natural person, is the managing member of, and holder of a controlling interest in, Advisors. Pursuant to those relationships, Advisors and Capital have discretionary investment management authority with respect to the assets of OPI III and Associates. Such authority includes the power to vote and otherwise dispose of securities purchased by OPI III and Associates. Each of Capital, Advisors and Isaly may be deemed to have a pecuniary interest in Shares and warrants to purchase Shares ("Warrants") beneficially owned by OPI III and each of Advisors and Isaly may be deemed to have a pecuniary interest in Shares and Warrants beneficially owned by Associates.

F4: This Form 3 is being jointly filed by Capital, Advisors and Isaly. Each of the Reporting Persons disclaims beneficial ownership of the securities reported herein except to the extent of its or his pecuniary interest therein, if any. This report shall not be deemed an admission that the Reporting Persons are beneficial owners for the purpose of Section 16 of the Securities Exchange Act of 1934, as amended, or for any other purpose.

F5: The Warrants reported herein as indirectly beneficially owned by Capital, Advisors and Isaly are directly owned by OPI III and Associates. Of this amount, OPI III and Associates hold 3,466,981 and 33,019 Warrants, respectively. Capital, pursuant to its authority as the general partner of OPI III, may be considered to hold indirectly 3,466,981 Warrants and Advisors, pursuant to its authority as the managing member of Capital and general partner of Associates, may be considered to hold indirectly 3,500,000 Warrants.

F6: The Reporting Persons have designated a representative, currently Carl L. Gordon ("Gordon"), a member of Advisors, to serve on the Issuer's board of directors. On February 20, 2010, Gordon was granted a stock option under the Amarin Corporation plc 2002 Stock Option Plan (the "Option"). The Option will vest in four equal installments on each anniversary of such grant date.

F7: Pursuant to an agreement with Advisors, Gordon is obligated to transfer any Shares issued under the Option reported herein to Advisors, which will distribute the Shares to OPI III and Associates on a pro-rata basis.