Alkermes plc. — Director's Dealing 2012

May 18, 2012

SEC Form 4 — Statement of Changes in Beneficial Ownership

Issuer: Alkermes plc. (ALKS)
CIK: 0001520262
Period of Report: 2012-05-17

Reporting Person: Ehrich Elliot (SVP, R&D & CMO, Alkermes, Inc.)

Non-Derivative Transactions

Date	Security	Code	Shares	Price	A/D	Holdings After	Ownership
2012-05-17	Ordinary Shares	M	4175	—	Acquired	22254	Direct
2012-05-17	Ordinary Shares	F	1324	$16.71	Disposed	20930	Direct

Derivative Transactions

Date	Security	Exercise Price	Code	Shares	A/D	Expiration	Underlying	Ownership
2012-05-17	Restricted Stock Unit Award	$0	M	4175	Disposed		Ordinary Shares (4175)	Direct

Footnotes

F1: Shares subject to the restricted stock unit award vest in equal annual installments over a four year period, commencing on 5/17/11.