X0306 4 2022-09-14 0 0000882361 Aptose Biosciences Inc. APTO 0001789042 Seizinger Bernd R. C/O APTOSE BIOSCIENCES INC. 251 CONSUMERS ROAD, SUITE 1105 TORONTO A6 M2J 4R3 ONTARIO, CANADA 1 0 0 0 Stock Option (right to buy) 0.74 2022-09-14 4 A 0 50000 0 A 2032-09-14 Common Shares 50000 50000 D Fifty percent (50%) of the options vest on September 14, 2023, twenty-five percent (25%) on September 14, 2024, and twenty-five percent (25%) on September 14, 2025. /s/ Leslie Auld as attorney-in-fact for Bernd R. Seizinger 2022-09-15