Pretreatment with desethyl KBT-3022 (0.1, 0.3, and 1 mg/kg, i.v.) prolongs the time required to achieve thrombotic occlusion in the femoral artery and inhibits collagen-induced platelet aggregation in whole blood ex vivo. Desethyl KBT-3022 (1–40 μM) inhibits the thrombin-induced aggregation of washed platelets in a concentration-dependent manner.