X0306 4 2013-07-29 0 0001439222 AGIOS PHARMACEUTICALS INC AGIO 0001508052 Flagship Ventures Fund 2007, L.P. ONE MEMORIAL DRIVE 7TH FLOOR CAMBRIDGE MA 02142 0 0 1 0 0001222012 AFEYAN NOUBAR ONE MEMORIAL DRIVE 7TH FLOOR CAMBRIDGE MA 02142 0 0 1 0 0001255927 KANIA EDWIN M JR ONE MEMORIAL DRIVE 7TH FLOOR CAMBRIDGE MA 02142 0 0 1 0 0001508053 Flagship Ventures 2007 General Partner LLC ONE MEMORIAL DRIVE 7TH FLOOR CAMBRIDGE MA 02142 0 0 1 0 Common Stock 2013-07-29 4 C 0 3860738 0.00 A 3860738 D Series A Convertible Preferred Stock 2013-07-29 4 C 0 10000000 D Common Stock 3636363 0 D Series C-2 Convertible Preferred Stock 2013-07-29 4 C 0 617031 D Common Stock 224375 0 D Represents the total number of shares received upon conversion of shares of the Issuer's Series A Convertible Preferred Stock (the "Series A Shares") and Series C-2 Convertible Preferred Stock (the "Series C-2 Shares", and together with the Series A Shares, collectively, the "Preferred Shares"). These shares are held by Flagship Ventures Fund 2007, L.P. ("Flagship 2007"). Flagship Ventures 2007 General Partner, LLC ("Flagship 2007 LLC") is the general partner of Flagship 2007. Noubar B. Afeyan Ph.D. and Edwin M. Kania, Jr. are the managers of Flagship 2007 LLC. Flagship 2007 LLC and each of these individuals may be deemed to share voting and investment power with respect to all shares held by Flagship 2007. Each of the filing persons disclaims beneficial ownership of the shares except to the extent of any pecuniary interest therein. Effective upon the closing of the Issuer's initial public offering of its Common Stock, each Preferred Share automatically converted at a ratio of 1-for-2.75 into the number of shares of Common Stock shown in column 7. The Preferred Shares had no expiration date. By: /s/ Noubar B. Afeyan Ph. D., for Flagship Ventures Fund 2007, L.P. as Manager of Flagship Ventures 2007 General Partner LLC, its General Partner 2013-07-31 By: /s/ Noubar B. Afeyan Ph. D. 2013-07-31 /s/ Edwin M. Kania, Jr. 2013-07-31 /s/ Noubar B. Afeyan Ph. D., as Manager of Flagship Ventures 2007 General Partner LLC 2013-07-31