X0202 4 2007-11-30 1 0001388775 Sirtris Pharmaceuticals, Inc. SIRT 0001295438 Polaris Venture Management Co IV LLC C/O POLARIS VENTURE PARTNERS 1000 WINTER STREET WALTHAM MA 02451 0 0 1 0 0001018394 SPOON ALAN G C/O POLARIS VENTURE PARTNERS 1000 WINTER STREET WALTHAM MA 02451 0 0 1 0 0001295676 Flint Jonathan A C/O POLARIS VENTURE PARTNERS 1000 WINTER STREET WALTHAM MA 02451 0 0 1 0 0001117003 MCGUIRE TERRANCE C/O POLARIS VENTURE PARTNERS 1000 WINTER STREET WALTHAM MA 02451 0 0 1 0 0001157864 POLARIS VENTURE PARTNERS IV LP C/O POLARIS VENTURE PARTNERS 1000 WINTER STREET WALTHAM MA 02451 0 0 1 0 0001170720 POLARIS VENTURE PARTNERS ENTREPRENEURS FUND IV LP C/O POLARIS VENTURE PARTNERS 1000 WINTER STREET WALTHAM MA 02451 0 0 1 0 Common Stock 2007-11-30 4 J 0 982212 0 D 2208485 I See Footnote Common Stock 2007-11-30 4 J 0 17788 0 D 39995 I See Footnote Pro-rata distribution from Polaris Venture Partners IV, L.P. ("PVP IV") to the limited partners of PVP IV. 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. Pro-rata distribution from Polaris Venture Partners Entrepreneurs' Fund IV, L.P. ("PVPE IV") to the limited partners of PVPE IV. 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 2007-12-04 /s/ Jonathan A. Flint 2007-12-04 /s/ Terrance G. McGuire 2007-12-04 /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. 2007-12-04 /s/ Donald MacKenzie Venture Partners IV, L.P. By: Donald MacKenzie Authorized signatory for Polaris Venture Partners IV, L.P. 2007-12-04 /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. 2007-12-04