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 *
Holtzman Steven H
  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)
CEO
(Last)
(First)
(Middle)
C/O INFINITY PHARMACEUTICALS, INC., 780 MEMORIAL DRIVE
3. Date of Earliest Transaction (Month/Day/Year)
10/27/2008
(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 10/27/2008   M   55,257 (1) A $ 2.04 312,183 D  
Common Stock 10/27/2008   M   331 A $ 3.48 312,514 D  
Common Stock 10/27/2008   M   33,154 (2) A $ 3.48 401,256 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
Stock Option (right to buy) $ 2.04 10/27/2008   M     55,257 (3)   (4) 05/10/2015 Common Stock 55,257 $ 0 0 D  
Stock Option (right to buy) $ 3.48 10/27/2008   M     331   (5) 03/31/2016 Common Stock 331 $ 0 0 D  
Stock Option (right to buy) $ 3.48 10/27/2008   M     33,154   (6) 03/31/2016 Common Stock 33,154 $ 0 0 D  

Reporting Owners

Reporting Owner Name / Address Relationships
 Director  10% Owner  Officer  Other
Holtzman Steven H
C/O INFINITY PHARMACEUTICALS, INC.
780 MEMORIAL DRIVE
CAMBRIDGE, MA 02139
  X     CEO  

Signatures

 /s/ Steven H. Holtzman   10/29/2008
**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) The shares were acquired upon the exercise of a stock option which was subject to a right of early exercise, pursuant to which the optionee could exercise unvested stock options and receive, in lieu thereof, shares of restricted stock that are subject to a right of repurchase by Infinity Pharmaceuticals, Inc. ("Infinity") that lapses in accordance with the vesting schedule of the original option. Of such 55,257 shares, 51,803 shares were vested as of the date of exercise of the stock option and the remaining 3,454 shares are subject to a right of repurchase by Infinity that lapses in accordance with the vesting schedule of the original option, which schedule was as follows: the option vested annually in equal installments for four years, beginning on January 31, 2005.
(2) The shares were acquired upon the exercise of a stock option which was subject to a right of early exercise, pursuant to which the optionee could exercise unvested stock options and receive, in lieu thereof, shares of restricted stock that are subject to a right of repurchase by Infinity that lapses in accordance with the vesting schedule of the original option. Of such 33,154 shares, 22,794 shares were vested as of the date of exercise of the stock option and the remaining 10,360 shares are subject to a right of repurchase by Infinity that lapses in accordance with the vesting schedule of the original option, which schedule was as follows: the option vested annually in equal installments for four years, beginning on February 1, 2006.
(3) The stock option was inadvertently previously reported as a stock option to buy 55,256 shares, on a Form 4 filed on September 13, 2006.
(4) The stock option was subject to a right of early exercise, pursuant to which the optionee could exercise unvested stock options and receive, in lieu thereof, shares of restricted stock that are subject to a right of repurchase by Infinity that lapses in accordance with the vesting schedule of the original option. The optionee exercised the stock option in full. The vesting schedule of the original option was as follows: the option vested annually in equal installments for four years, beginning on January 31, 2005. As such, as of the date of exercise, the option was vested as to 51,803 shares.
(5) The option vested in equal monthly installments for 1 year, beginning on February 1, 2006.
(6) The stock option was subject to a right of early exercise, pursuant to which the optionee could exercise unvested stock options and receive, in lieu thereof, shares of restricted stock that are subject to a right of repurchase by Infinity that lapses in accordance with the vesting schedule of the original option. The optionee exercised the stock option in full. The vesting schedule of the original option was as follows: the option vested annually in equal installments for four years, beginning on February 1, 2006. As such, as of the date of exercise, the option was vested as to 22,794 shares.

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