Acalabrutinib (ACP-196) and ONO/GS-4059 inhibit plaque-induced, but not collagen-induced, platelet thrombus formation under arterial flow. Blood samples were incubated with DiOC6 for platelet labeling and with solvent (0.1% DMSO) or increasing concentrations of ACP-196 (ACP) or ONO/GS-4059 (ONO) (all in DMSO, final concentration of 0.1%) for 15 minutes before the start of blood flow at a shear rate of 600/s. The line graphs show the effects of ACP (A) and ONO (B) on the kinetics of plaque- and collagen-induced platelet deposition. Data are mean + SD (n = 5 for ACP; n = 6 for 0.5 μM ONO; n = 6 for 1 µM ONO; n = 7 for 2 µM ONO; n = 7 for 5 μM ONO). Statistically significant differences compared with DMSO control are indicated 5 minutes after the start of blood flow. *P < .05, *** P < .001. Other statistically significant differences after pairwise comparisons are ACP 0.5 µM vs ACP 2 μM, P < .05; ONO 5 µM vs ONO 2 µM, P < .001; ONO 5 µM vs ONO 1 µM, P < .001; and ONO 5 µM vs ONO 0.5 µM, P < .001.