Effect of oral ibrutinib intake (loading dose and low maintenance dose) on platelet aggregation in static and flow assays in 2 volunteers. (A) Rapid suppression of plaque-induced platelet aggregation by oral intake of 420 mg of ibrutinib. Blood was collected before (control) and 3 hours after the intake of 3 × 140 mg of ibrutinib (donor B). (B) Platelet inhibition is maintained by low-dose ibrutinib for 1 week. Blood was collected after the intake of 140 mg/d of ibrutinib (donor A) or 140 mg of ibrutinib on alternate days (donor B) for 1 week. Static platelet aggregation induced with 2 pools of plaque homogenate (A and B; 833 μg/mL), collagen (0.2 μg/mL), TRAP (5 μM), ADP (5 μM), or AA (0.6 mM) (left panels). Kinetics of plaque- and collagen- induced platelet thrombus formation under arterial flow (600/s) in donor A and donor B (right panels). Data are mean + SD of triplicates.