X0306 4 2018-10-01 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 2018-10-01 4 S 0 5000 2.82 D 609561 D Common Stock 16446.7945 I 401(K) The disposition reported on this Form 4 was effected pursuant to a Rule 10b5-1 trading plan adopted by the reporting person on November 17, 2017. The price reported in this line of Column 4 is a weighted average price. The shares were sold in multiple transactions at prices ranging from $2.80 to $2.88, 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 sold at each separate price within the ranges set forth in this footnote 2. Includes 7,309 shares of common stock acquired by Ms. Perkins on June 16, 2018 through participation in the issuer's Employee Stock Purchase Plan. /s/ Adelene Perkins 2018-10-02