Alkermes plc. — Director's Dealing 2012

May 29, 2012

SEC Form 4 — Statement of Changes in Beneficial Ownership

Issuer: Alkermes plc. (ALKS)
CIK: 0001520262
Period of Report: 2012-05-26

Reporting Person: BIBERSTEIN KATHRYN L (SVP, GC, Secretary, Alks, Inc.)

Non-Derivative Transactions

Date	Security	Code	Shares	Price	A/D	Holdings After	Ownership
2012-05-26	Ordinary Shares	M	2125	—	Acquired	41254	Direct
2012-05-26	Ordinary Shares	F	674	$16.14	Disposed	40580	Direct
2012-05-27	Ordinary Shares	F	476	$16.14	Disposed	40104	Direct

Derivative Transactions

Date	Security	Exercise Price	Code	Shares	A/D	Expiration	Underlying	Ownership
2012-05-26	Restricted Stock Award	$0	M	2125	Disposed		Ordinary Shares (2125)	Direct

Footnotes

F1: Shares subject to the restricted stock unit award vest in equal annual installments over a four year period, commencing on 5/26/10.