X0306 4 2020-02-03 0 0001501989 CytomX Therapeutics, Inc. CTMX 0001645600 HANNAH ALISON L. C/O CYTOMX THERAPEUTICS, INC. 151 OYSTER POINT BLVD., STE. 400 SOUTH SAN FRANCISCO CA 94080 0 1 0 0 Chief Medical Officer Stock Option (Right to Buy) 7.71 2020-02-03 4 A 0 250000 0.00 A 2030-02-02 Common Stock 250000 250000 D The shares subject to the Inducement Option Award will vest and become exercisable as to 25% of the total number of shares subject to the option on February 3, 2021 and with respect to 1/48th of the total number of shares subject to the option in successive, equal monthly installments on each monthly anniversary thereafter, subject to the Reporting Person's continued employment with the Issuer on each such vesting date. /s/ Lloyd Rowland, as Attorney-in-Fact for Alison L. Hannah 2020-02-04