SEC Form 4

FORM 4		UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 STATEMENT OF CHANGES IN BENEFICIAL OWNERSHIP Filed pursuant to Section 16(a) of the Securities Exchange Act of 1934 or Section 30(h) of the Investment Company Act of 1940	OMB APPROVAL OMB Number: 3235-0287 Estimated average burden hours per response: 0.5
	Check this box if no longer subject to Section 16. Form 4 or Form 5 obligations may continue. See Instruction 1(b).

1. Name and Address of Reporting Person* Peterson Rebecca (Last) (First) (Middle) 852 WINTER ST. (Street) WALTHAM MA 02451 (City) (State) (Zip)	2. Issuer Name and Ticker or Trading Symbol Alkermes plc. [ ALKS ]	5. Relationship of Reporting Person(s) to Issuer (Check all applicable) Director 10% Owner X Officer (give title below) Other (specify below) SVP, Corporate Communications
	3. Date of Earliest Transaction (Month/Day/Year) 03/03/2015
	4. If Amendment, Date of Original Filed (Month/Day/Year)	6. Individual or Joint/Group Filing (Check Applicable Line) X Form filed by One Reporting Person Form filed by More than One Reporting Person

Table I - Non-Derivative Securities Acquired, Disposed of, or Beneficially Owned
1. Title of Security (Instr. 3)	2. Transaction Date (Month/Day/Year)	2A. Deemed Execution Date, if any (Month/Day/Year)	3. Transaction Code (Instr. 8)		4. Securities Acquired (A) or Disposed Of (D) (Instr. 3, 4 and 5)			5. Amount of Securities Beneficially Owned Following Reported Transaction(s) (Instr. 3 and 4)	6. Ownership Form: Direct (D) or Indirect (I) (Instr. 4)	7. Nature of Indirect Beneficial Ownership (Instr. 4)
			Code	V	Amount	(A) or (D)	Price
Ordinary Shares	03/03/2015		M(1)		15,375	A	$47.16	15,375	D
Ordinary Shares	03/03/2015		S(2)		14,600	D	$71.27(3)	775	D
Ordinary Shares	03/03/2015		S(2)		775	D	$72.0387(4)	0	D
Ordinary Shares	03/03/2015		M		3,500	A	$0	3,500	D
Ordinary Shares	03/03/2015		F		1,138	D	$72.8	2,362	D
Ordinary Shares	03/05/2015		S(2)		2,362	D	$71.8019(5)	0	D

Table II - Derivative Securities Acquired, Disposed of, or Beneficially Owned (e.g., puts, calls, warrants, options, convertible securities)
1. Title of Derivative Security (Instr. 3)	2. Conversion or Exercise Price of Derivative Security	3. Transaction Date (Month/Day/Year)	3A. Deemed Execution Date, if any (Month/Day/Year)	4. Transaction Code (Instr. 8)		5. Number of Derivative Securities Acquired (A) or Disposed of (D) (Instr. 3, 4 and 5)		6. Date Exercisable and Expiration Date (Month/Day/Year)		7. Title and Amount of Securities Underlying Derivative Security (Instr. 3 and 4)		8. Price of Derivative Security (Instr. 5)	9. Number of derivative Securities Beneficially Owned Following Reported Transaction(s) (Instr. 4)	10. Ownership Form: Direct (D) or Indirect (I) (Instr. 4)	11. Nature of Indirect Beneficial Ownership (Instr. 4)
				Code	V	(A)	(D)	Date Exercisable	Expiration Date	Title	Amount or Number of Shares
Employee Stock Option (Right to Buy)	$47.16	03/03/2015		M(1)			15,375	03/03/2015(6)	03/03/2024	Ordinary Shares	15,375	$0	46,125	D
Restricted Stock Unit Award	$0	03/03/2015		M			3,500	03/03/2015(7)	(7)	Ordinary Shares	3,500	$0	10,500	D

Explanation of Responses:

1. This option exercise was effected pursuant to a Rule 10b5-1 trading plan adopted by the reporting person.

2. This sale was effected pursuant to a Rule 10b5-1 trading plan adopted by the reporting person.

3. The price reported in Column 4 is a weighted average price. The shares were sold in multiple transactions at prices ranging from $70.82 to $71.75. Full information regarding the number of shares sold at each separate price can be furnished to the SEC staff upon request.

4. The price reported in Column 4 is a weighted average price. The shares were sold in multiple transactions at prices ranging from $71.82 to $72.18. Full information regarding the number of shares sold at each separate price can be furnished to the SEC staff upon request.

5. The price reported in Column 4 is a weighted average price. The shares were sold in multiple transactions at prices ranging from $71.36 to $72.1264. Full information regarding the number of shares sold at each separate price can be furnished to the SEC staff upon request.

6. Shares subject to the stock option award vest in four equal annual installments commencing on 3/3/15.

7. Shares subject to the restricted stock unit award vest in equal annual installments over a four year period, commencing 3/3/2015.

	/s/ Jennifer Baptiste, attorney-in-fact for Rebecca Peterson	03/05/2015
	** Signature of Reporting Person	Date
Reminder: Report on a separate line for each class of securities beneficially owned directly or indirectly.
* If the form is filed by more than one reporting person, see Instruction 4 (b)(v).
** Intentional misstatements or omissions of facts constitute Federal Criminal Violations See 18 U.S.C. 1001 and 15 U.S.C. 78ff(a).
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