X0306 4 2019-06-25 0 0001496671 Calithera Biosciences, Inc. CALA 0001553389 Molineaux Susan C/O CALITHERA BIOSCIENCES, INC. 343 OYSTER POINT BLVD. #200 SOUTH SAN FRANCISCO CA 94080 1 1 0 0 PRESIDENT AND CEO Common Stock 2019-06-25 4 P 0 51600 3.88 A 457188 I By Trust Common Stock 2500 I By Spouse Common Stock 2500 D The price reported is a weighted average price. These shares were purchased in multiple transactions at prices ranging from $3.8278 to $3.8938. The reporting person undertakes to provide to the Company, any security holder of the Company, 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 footnote (1) to this Form 4. Includes 2,500 shares acquired under the Company's 2014 Employee Stock Purchase Plan on December 10, 2018. Shares are held by the Molineaux Family Trust, of which the Reporting Person is a Trustee, including 5,000 shares transferred from the Reporting Person and 5,000 shares transferred from the Reporting Person's spouse, to the Molineaux Family Trust on March 27, 2019. Includes 2,500 shares acquired under the Company's 2014 Employee Stock Purchase Plan on June 10, 2019. /s/ Susan M. Molineaux 2019-06-27