X0306 4 2017-07-17 0 0001496671 Calithera Biosciences, Inc. CALA 0001670740 Orford Keith C/O CALITHERA BIOSCIENCES, INC. 343 OYSTER POINT BLVD. #200 SOUTH SAN FRANCISCO CA 94080 0 1 0 0 SR. VP, CLINICAL DEVELOPMENT Common Stock 2017-07-17 4 S 0 2120 18.3126 D 6879 D Reported transaction occurred pursuant to a Rule10b5-1 Trading Plan adopted on June 16, 2017. The price reported in Column 4 is a weighted average price. These shares were sold in multiple transactions at prices ranging from $17.90 to $18.675, inclusive. The reporting person undertakes to provide to the Issuer, any security holder of the Issuer, 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 range set forth above. Includes 6,879 shares acquired under the Company's 2014 Employee Stock Purchase Plan on May 13, 2016, November 15, 2016 and June 9, 2017. /s/ Keith Orford 2017-07-19