Ownership Submission
FORM 4
Check this box if no longer subject to Section 16. Form 4 or Form 5 obligations may continue. See Instruction 1(b).
UNITED STATES SECURITIES AND EXCHANGE COMMISSION
Washington, D.C. 20549

STATEMENT OF CHANGES IN BENEFICIAL OWNERSHIP OF SECURITIES

Filed pursuant to Section 16(a) of the Securities Exchange Act of 1934, Section 17(a) of the Public Utility Holding Company Act of 1935 or Section 30(h) of the Investment Company Act of 1940
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(Print or Type Responses)
1. Name and Address of Reporting Person *
POPS RICHARD F
  2. Issuer Name and Ticker or Trading Symbol
Alkermes plc. [ALKS]
5. Relationship of Reporting Person(s) to Issuer
(Check all applicable)
__X__ Director _____ 10% Owner
__X__ Officer (give title below) _____ Other (specify below)
Director and CEO, Alkermes plc
(Last)
(First)
(Middle)
TREASURY BUILDING, LOWER GRAND CANAL STREET
3. Date of Earliest Transaction (Month/Day/Year)
09/16/2011
(Street)

DUBLIN 2 
4. If Amendment, Date 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
(City)
(State)
(Zip)
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
Common Stock 09/16/2011   A   424,354 A (12) 424,354 D  

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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 Underlying Securities
(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 of Derivative Security: 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) $ 8.55 09/16/2011   A   220,000     (1) 05/26/2019 Common Stock 220,000 (2) 220,000 D  
Employee Stock Option (Right to Buy) $ 9.21 09/16/2011   A   500,000     (3) 11/18/2019 Common Stock 500,000 (2) 500,000 D  
Employee Stock Option (Right to Buy) $ 12.29 09/16/2011   A   170,000     (4) 05/27/2018 Common Stock 170,000 (2) 170,000 D  
Employee Stock Option (Right to Buy) $ 14.13 09/16/2011   A   50,000     (5) 11/05/2017 Common Stock 50,000 (2) 50,000 D  
Employee Stock Option (Right to Buy) $ 11.74 09/16/2011   A   325,000     (6) 05/17/2020 Common Stock 325,000 (2) 325,000 D  
Employee Stock Option (Right to Buy) $ 18.105 09/16/2011   A   400,000     (7) 05/20/2021 Common Stock 400,000 (2) 400,000 D  
Incentive Stock Option (Right to Buy) $ 4.77 09/16/2011   A   20,968     (8) 07/18/2012 Common Stock 20,968 (2) 20,968 D  
Incentive Stock Option (Right to Buy) $ 9.97 09/16/2011   A   10,030     (8) 04/25/2013 Common Stock 10,030 (2) 10,030 D  
Incentive Stock Option (Right to Buy) $ 12.3 09/16/2011   A   8,130     (8) 07/12/2014 Common Stock 8,130 (2) 8,130 D  
Incentive Stock Option (Right to Buy) $ 15.95 09/16/2011   A   6,269     (8) 06/01/2017 Common Stock 6,269 (2) 6,269 D  
Incentive Stock Option (Right to Buy) $ 18.6 09/16/2011   A   5,376     (8) 12/09/2015 Common Stock 5,376 (2) 5,376 D  
Incentive Stock Option (Right to Buy) $ 19.4 09/16/2011   A   5,155     (8) 10/02/2011 Common Stock 5,155 (2) 5,155 D  
Incentive Stock Option (Right to Buy) $ 20.79 09/16/2011   A   4,810     (8) 05/02/2016 Common Stock 4,810 (2) 4,810 D  
Non Qualified Stock Option (Right to Buy) $ 4.77 09/16/2011   A   104,032     (8) 07/18/2012 Common Stock 104,032 (2) 104,032 D  
Non Qualified Stock Option (Right to Buy) $ 7.36 09/16/2011   A   350,000     (8) 12/12/2012 Common Stock 350,000 (2) 350,000 D  
Non Qualified Stock Option (Right to Buy) $ 9.97 09/16/2011   A   156,220     (8) 04/25/2013 Common Stock 156,220 (2) 156,220 D  
Non Qualified Stock Option (Right to Buy) $ 12.16 09/16/2011   A   184,125     (8) 12/10/2013 Common Stock 184,125 (2) 184,125 D  
Non Qualified Stock Option (Right to Buy) $ 12.3 09/16/2011   A   141,870     (8) 07/12/2014 Common Stock 141,870 (2) 141,870 D  
Non Qualified Stock Option (Right to Buy) $ 14.38 09/16/2011   A   120,000     (8) 12/12/2016 Common Stock 120,000 (2) 120,000 D  
Non Qualified Stock Option (Right to Buy) $ 14.57 09/16/2011   A   149,625     (8) 10/17/2013 Common Stock 149,625 (2) 149,625 D  
Non Qualified Stock Option (Right to Buy) $ 14.9 09/16/2011   A   350,000     (8) 12/17/2014 Common Stock 350,000 (2) 350,000 D  
Non Qualified Stock Option (Right to Buy) $ 15.95 09/16/2011   A   93,731     (8) 06/01/2017 Common Stock 93,731 (2) 93,731 D  
Non Qualified Stock Option (Right to Buy) $ 18.6 09/16/2011   A   182,124     (8) 12/09/2015 Common Stock 182,124 (2) 182,124 D  
Non Qualified Stock Option (Right to Buy) $ 19.4 09/16/2011   A   244,845     (8) 10/02/2011 Common Stock 244,845 (2) 244,845 D  
Non Qualified Stock Option (Right to Buy) $ 20.79 09/16/2011   A   88,940     (8) 05/02/2016 Common Stock 88,940 (2) 88,940 D  
Restricted Stock Award $ 0 09/16/2011   A   250,000     (9)   (9) Common Stock 250,000 (10) 250,000 D  
Restricted Stock Award $ 0 09/16/2011   A   25,000     (11) 05/26/2014(11) Common Stock 25,000 (10) 25,000 D  
Restricted Stock Unit Award $ 0 09/16/2011   A   24,375     (6)   (6) Common Stock 24,375 (2) 24,375 D  
Restricted Stock Unit Award $ 0 09/16/2011   A   32,500     (7)   (7) Common Stock 32,500 (10) 32,500 D  

Reporting Owners

Reporting Owner Name / Address Relationships
 Director  10% Owner  Officer  Other
POPS RICHARD F
TREASURY BUILDING
LOWER GRAND CANAL STREET
DUBLIN 2 
  X     Director and CEO, Alkermes plc  

Signatures

 /s/ Jennifer Baptiste, attorney-in-fact for Richard F. Pops   09/20/2011
**Signature of Reporting Person Date

Explanation of Responses:

* 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).
(1) 50% vested as of 9/16/11, remainder vests in 2 equal annual installments beginning on 5/26/12.
(2) Received in exchange for, and having substantially the same terms as, stock options of Alkermes, Inc. common stock in connection with the Merger.
(3) 25% vested as of 9/16/11, remainder vests in 3 equal annual installments beginning on 11/18/11.
(4) 75% vested as of 9/16/11, remainder vests on 5/27/12.
(5) 75% vested as of 9/16/11, remainder vests on 11/5/11.
(6) 25% vested as of 9/16/11, remainder vests in 3 equal annual installments beginning on 5/17/12.
(7) Vests in 4 equal annual installments beginning on 5/20/12.
(8) These options are fully vested in accordance with their terms.
(9) 50% vests on 11/18/12 and 50% vests on 11/18/13.
(10) Received in exchange for, and having substantially the same terms as, restricted stock unit awards of Alkermes, Inc. common stock in connection with the Merger.
(11) Performance-based restricted stock unit award. Commencing on 5/26/10, a determination will be made if the performance criteria have been met. Shares subject to the award vest in full upon the achievement of the performance criteria. If such performance criteria have not been met within a period of five years from the date of grant, all of the shares subject to the award are forfeited.
(12) Received in exchange for shares of Alkermes, Inc. common stock in connection with the merger of Alkermes, Inc. and the global drug delivery technologies business of Elan (the "Merger"). On 9/16/11, the effective date of the Merger, the closing price of ALKS was $16.57 per share.

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