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 * Rosebay Medical Co L.P.   2. Issuer Name and Ticker or Trading Symbol INFINITY PHARMACEUTICALS, INC. [INFI] 5. Relationship of Reporting Person(s) to Issuer (Check all applicable) _____ Director __X__ 10% Owner _____ Officer (give title below) _____ Other (specify below) (Last) (First) (Middle) C/O NORTH BAY ASSOCIATES, 14000 QUAIL SPRINGS PARKWAY #2200 3. Date of Earliest Transaction (Month/Day/Year) 09/07/2012 (Street) OKLAHOMA CITY, OK 73134 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               3,000,000 D   Common Stock 09/07/2012   P   5,416,565 A $ 14.5 5,416,565 I By Purdue Pharma L.P. (1)

Reminder: Report on a separate line for each class of securities beneficially owned directly or indirectly.
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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 Purchase Warrants (right to buy)

$ 20 (2)

01/07/2009

H(2)

500,000

01/07/2009

07/01/2010(2)

Common Stock

500,000

$ 0 (2)

0

D

Stock Purchase Warrants (right to buy)

$ 30 (2)

01/07/2009

H(2)

1,000,000

01/07/2009

07/01/2011(2)

Common Stock

1,000,000

$ 0 (2)

0

D

Stock Purchase Warrants (right to buy)

$ 40 (2)

01/07/2009

H(2)

1,500,000

01/07/2009

07/02/2012(2)

Common Stock

1,500,000

$ 0 (2)

0

D

Reporting Owners

Reporting Owner Name / Address	Relationships
	Director	10% Owner	Officer	Other
Rosebay Medical Co L.P. C/O NORTH BAY ASSOCIATES 14000 QUAIL SPRINGS PARKWAY #2200 OKLAHOMA CITY, OK 73134		X

Signatures

/s/ Frank S. Vellucci, as Assistant Secretary of Rosebay Medical Company, Inc., the general partner of Rosebay Medical Company L.P.		09/07/2012
**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)	These securities were purchased by Purdue Pharma L.P. pursuant to the Securities Purchase Agreement between the Issuer, Purdue Pharma L.P., Beacon Company and the Reporting Person, dated July 17, 2012 (the "Securities Purchase Agreement"). The Reporting Person and Beacon Company are the ultimate parents of Purdue Pharma L.P. The Reporting Person disclaims beneficial ownership of these securities except to the extent of its pecuniary interest therein.
(2)	These warrants expired and were not exercised by the holder.

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