X0306 4 2017-12-06 0 0001113148 INFINITY PHARMACEUTICALS, INC. INFI 0001244822 BLOCH LAWRENCE E C/O INFINITY PHARMACEUTICALS, INC. 784 MEMORIAL DRIVE CAMBRIDGE MA 02139 0 1 0 0 President Common Stock 2017-12-06 4 P 0 500000 1.81 A 580944 D Common Stock 8958.82 I 401(k) The price reported in Column 4 is a weighted average price. The shares were purchased in multiple transactions at prices ranging from $1.79 to $1.8246, inclusive. The reporting person undertakes to provide to Infinity Pharmaceuticals, Inc., any security holder of Infinity Pharmaceuticals, Inc. or the staff of the Securities and Exchange Commission, upon request, full information regarding the number of shares purchased at each separate price within the ranges set forth in this footnote 1. /s/Lawrence E. Bloch 2017-12-07