X0306 4/A 2016-10-31 2016-11-02 0 0001113148 INFINITY PHARMACEUTICALS, INC. INFI 0001375124 Perkins Adelene Q C/O INFINITY PHARMACEUTICALS, INC. 784 MEMORIAL DRIVE CAMBRIDGE MA 02139 1 1 0 0 Chief Executive Officer Common Stock 2016-10-31 4 A 0 85800 0.00 A 449220 D Common Stock 9055.26 I 401(k) Represents shares from a grant of performance-based restricted stock on July 22, 2016. Upon the determination by the Compensation Committee of our Board of Directors, such shares vested in full on October 31, 2016. This amendment is being filed to correct the total amount of securities beneficial owned following the reported transaction to reflect 1,809 shares of common stock purchased through the issuer's Employee Stock Purchase Plan on June 30, 2016. /s/ Adelene Q. Perkins 2017-04-14