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
X	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* Polaris Venture Management Co IV LLC (Last) (First) (Middle) C/O POLARIS VENTURE PARTNERS 1000 WINTER STREET (Street) WALTHAM MA 02451 (City) (State) (Zip)	2. Issuer Name and Ticker or Trading Symbol Sirtris Pharmaceuticals, Inc. [ SIRT ]	5. Relationship of Reporting Person(s) to Issuer (Check all applicable) Director X 10% Owner Officer (give title below) Other (specify below)
	3. Date of Earliest Transaction (Month/Day/Year) 11/30/2007
	4. If Amendment, Date of Original Filed (Month/Day/Year)	6. Individual or Joint/Group Filing (Check Applicable Line) Form filed by One Reporting Person X 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
Common Stock	11/30/2007		J(1)		982,212	D	$0	2,208,485	I	See Footnote(2)
Common Stock	11/30/2007		J(3)		17,788	D	$0	39,995	I	See Footnote(4)

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

1. Name and Address of Reporting Person* Polaris Venture Management Co IV LLC (Last) (First) (Middle) C/O POLARIS VENTURE PARTNERS 1000 WINTER STREET (Street) WALTHAM MA 02451 (City) (State) (Zip) Relationship of Reporting Person(s) to Issuer Director X 10% Owner Officer (give title below) Other (specify below)

1. Name and Address of Reporting Person* SPOON ALAN G (Last) (First) (Middle) C/O POLARIS VENTURE PARTNERS 1000 WINTER STREET (Street) WALTHAM MA 02451 (City) (State) (Zip) Relationship of Reporting Person(s) to Issuer Director X 10% Owner Officer (give title below) Other (specify below)

1. Name and Address of Reporting Person* Flint Jonathan A (Last) (First) (Middle) C/O POLARIS VENTURE PARTNERS 1000 WINTER STREET (Street) WALTHAM MA 02451 (City) (State) (Zip) Relationship of Reporting Person(s) to Issuer Director X 10% Owner Officer (give title below) Other (specify below)

1. Name and Address of Reporting Person* MCGUIRE TERRANCE (Last) (First) (Middle) C/O POLARIS VENTURE PARTNERS 1000 WINTER STREET (Street) WALTHAM MA 02451 (City) (State) (Zip) Relationship of Reporting Person(s) to Issuer Director X 10% Owner Officer (give title below) Other (specify below)

1. Name and Address of Reporting Person* POLARIS VENTURE PARTNERS IV LP (Last) (First) (Middle) C/O POLARIS VENTURE PARTNERS 1000 WINTER STREET (Street) WALTHAM MA 02451 (City) (State) (Zip) Relationship of Reporting Person(s) to Issuer Director X 10% Owner Officer (give title below) Other (specify below)

1. Name and Address of Reporting Person* POLARIS VENTURE PARTNERS ENTREPRENEURS FUND IV LP (Last) (First) (Middle) C/O POLARIS VENTURE PARTNERS 1000 WINTER STREET (Street) WALTHAM MA 02451 (City) (State) (Zip) Relationship of Reporting Person(s) to Issuer Director X 10% Owner Officer (give title below) Other (specify below)

Explanation of Responses:

1. Pro-rata distribution from Polaris Venture Partners IV, L.P. ("PVP IV") to the limited partners of PVP IV.

2. The reportable securities are owned directly by PVP IV. Polaris Venture Management Co. IV, L.L.C. ("PVM IV") is the general partner of PVP IV. PVM IV disclaims beneficial ownership of these securities and this report shall not be deemed an admission that PVM IV is the beneficial owner of such securities for purposes of Section 16 or for any other purpose, except to the extent of its pecuniary interest therein. Each of Jonathan A. Flint ("Flint"), Terrance G. McGuire ("McGuire") and Alan G. Spoon ("Spoon") are the managing members of PVM IV. Each of Flint, McGuire and Spoon disclaims beneficial ownership of these securities and this report shall not be deemed an admission that any of them is the beneficial owner of such securities for purposes of Section 16 or for any other purpose, except to the extent of their pecuniary interest therein.

3. Pro-rata distribution from Polaris Venture Partners Entrepreneurs' Fund IV, L.P. ("PVPE IV") to the limited partners of PVPE IV.

4. The reportable securities are owned directly by PVPE IV. PVM IV is the general partner of PVPE IV. PVM IV disclaims beneficial ownership of these securities and this report shall not be deemed an admission that PVM IV is the beneficial owner of such securities for purposes of Section 16 or for any other purpose, except to the extent of its pecuniary interest therein. Each of Flint, McGuire McGuire and Spoon are the managing members of PVM IV. Each of Flint, McGuire and Spoon disclaims beneficial ownership of these securities and this report shall not be deemed an admission that any of them is the beneficial owner of such securities for purposes of Section 16 or for any other purpose, except to the extent of their pecuniary interest therein.

	/s/ Alan Spoon	12/04/2007
	/s/ Jonathan A. Flint	12/04/2007
	/s/ Terrance G. McGuire	12/04/2007
	/s/ Donald MacKenzie Polaris Venture Management Co. IV, L.L.C. By: Donald MacKenzie Authorized signatory for Polaris Venture Management Co. IV, L.L.C.	12/04/2007
	/s/ Donald MacKenzie Venture Partners IV, L.P. By: Donald MacKenzie Authorized signatory for Polaris Venture Partners IV, L.P.	12/04/2007
	/s/ Donald MacKenzie Polaris Venture Partners Entrepreneurs' Fund IV, L.P. By: Donald MacKenzie Authorized signatory for Polaris Venture Partners Entrepreneurs' Fund IV, L.P.	12/04/2007
	** 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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