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 *
Perkins Adelene Q
   2. Issuer Name and Ticker or Trading Symbol
INFINITY PHARMACEUTICALS, INC. [INFI] 		5. Relationship of Reporting Person(s) to Issuer
(Check all applicable)
__X__ Director _____ 10% Owner
__X__ Officer (give title below) _____ Other (specify below)
Pres & Chief Executive Officer
(Last)
(First)
(Middle)
C/O INFINITY PHARMACEUTICALS, INC., 780 MEMORIAL DRIVE		 3. Date of Earliest Transaction (Month/Day/Year)
12/07/2012
(Street)

CAMBRIDGE, MA 02139		 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 12/07/2012   M   22,103 A $ 3.48 338,641 D  
Common Stock 12/07/2012   M   331 A $ 3.48 338,972 D  
Common Stock 12/07/2012   M   29,432 A $ 13.59 368,404 D  
Common Stock 12/07/2012   M   10,204 A $ 9.8 378,608 D  
Common Stock 12/07/2012   M   13,927 A $ 7.18 392,535 D  
Common Stock 12/07/2012   M   23,070 A $ 6.25 415,605 D  
Common Stock 12/07/2012   M   76,930 A $ 5.94 492,535 D  
Common Stock               5,684.474 (1) I 401(k)

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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
Stock Option (right to buy) $ 3.48 12/07/2012   M     22,103   (2) 03/31/2016 Common Stock 22,103 $ 0 0 D  
Stock Option (right to buy) $ 3.48 12/07/2012   M     331   (3) 03/31/2016 Common Stock 331 $ 0 0 D  
Stock Option (right to buy) $ 13.59 12/07/2012   M     29,432   (4) 01/24/2017 Common Stock 29,432 $ 0 0 D  
Stock Option (right to buy) $ 9.8 12/07/2012   M     10,204   (5) 12/13/2017 Common Stock 10,204 $ 0 0 D  
Stock Option (right to buy) $ 7.18 12/07/2012   M     13,927   (6) 12/04/2018 Common Stock 13,927 $ 0 0 D  
Stock Option (right to buy) $ 6.25 12/07/2012   M     23,070   (7) 01/05/2020 Common Stock 23,070 $ 0 340,930 D  
Stock Option (right to buy) $ 5.94 12/07/2012   M     76,930   (8) 01/06/2021 Common Stock 76,930 $ 0 83,620 D  

Reporting Owners

Reporting Owner Name / Address Relationships
 Director  10% Owner  Officer  Other
Perkins Adelene Q
C/O INFINITY PHARMACEUTICALS, INC.
780 MEMORIAL DRIVE
CAMBRIDGE, MA 02139		   X     Pres & Chief Executive Officer  

Signatures

 /s/Adelene Q. Perkins   12/10/2012
**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) Represents shares of Infinity Pharmaceuticals, Inc. common stock acquired under the Infinity Pharmaceuticals, Inc. 401(k) plan.
(2) This option was fully vested with respect to all 22,103 shares subject to the option as of the date hereof.
(3) This option was fully vested with respect to all 331 shares subject to the option as of the date hereof.
(4) This option was fully vested with respect to all 29,432 shares remaining subject to the option as of the date hereof.
(5) This option was fully vested with respect to all 10,204 shares remaining subject to the option as of the date hereof.
(6) This option was fully vested with respect to all 13,927 shares remaining subject to the option as of the date hereof.
(7) This option was vested with respect to 265,416 shares as of the date hereof and vests as to 1/48th of the 364,000 shares subject to the initial option at the end of each calendar month.
(8) This option was vested with respect to 76,930 shares as of the date hereof and vests as to 1/48th of the 160,550 shares subject to the initial option at the end of each calendar month.

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