RWJ-56110 dihydrochloride is a potent, selective, peptide-mimetic inhibitor of PAR-1 activation and internalization (binding IC 50 =0.44 uM) and shows no effect on PAR-2, PAR-3, or PAR-4. RWJ-56110 dihydrochloride inhibits the aggregation of human platelets induced by?both?SFLLRN-NH2?( IC 50 =0.16 μM) and thrombin ( IC 50 =0.34 μM), quite selective?relative to U46619. RWJ-56110 dihydrochloride blocks angiogenesis and blocks the formation of new vessels in vivo. RWJ-56110 dihydrochloride induces cell apoptosis .