X0306 4 2020-02-14 0 0001501989 CytomX Therapeutics, Inc. CTMX 0001578767 Kavanaugh William Michael C/O CYTOMX THERAPEUTICS, INC. 151 OYSTER POINT BLVD., STE. 400 SOUTH SAN FRANCISCO CA 94080 0 1 0 0 CSO, Head Res.&Non-Clin. Dev. Stock Option (right to buy) 7.13 2020-02-14 4 A 0 120000 0.00 A 2030-02-13 Common Stock 120000 120000 D 1/48th of the shares subject to the option vest on each monthly anniversary measured from January 1, 2020 (the "Vesting Commencement Date"), such that 100% of the shares subject to the option will be fully vested and exercisable on the fourth anniversary of the Vesting Commencement Date, subject to the Reporting Person's continued service to the Issuer through each such date. Exhibit 24.1 - Power of Attorney /s/ Lloyd Rowland, as Attorney-in-Fact for William Michael Kavanaugh 2020-02-19