X0306 4 2015-08-11 0 0001629137 Global Blood Therapeutics, Inc. GBT 0001192591 HOMCY CHARLES J C/O GLOBAL BLOOD THERAPEUTICS, INC. 400 EAST JAMIE COURT, SUITE 101 SOUTH SAN FRANCISCO CA 94080 1 0 0 0 Stock Option (right to buy) 20.00 2015-08-11 4 A 0 15000 A 2025-08-10 Common Stock 15000 15000 D The shares subject to this option shall vest and become exercisable in 12 equal monthly installments with the first installment on September 11, 2015, such that this option is fully exercisable on August 11, 2016. This option is subject to accelerated vesting upon a change of control of the Issuer. Not applicable. /s/ John Schembri, as Attorney-in-Fact 2015-08-13