Pharmacological Interruption of Acute Thrombus Formation with Minimal Hemorrhagic Complications by a Small Molecule Tissue Factor/Factor VIIa Inhibitor: Comparison to Factor Xa and Thrombin Inhibition in a Nonhuman Primate Thrombosis Model

This study was designed to evaluate the antithrombotic efficacy and bleeding propensity of a selective, small-molecule inhibitor of tissue factor/factor VIIa (TF/VIIa) in comparison to small-molecule, selective inhibitors of factor Xa and thrombin in a nonhuman primate model of thrombosis. Acute, spontaneous thrombus formation was induced by electrolytic injury to the intimal surface of a femoral blood vessel, which results in thrombus propagation at the injured site. The TF/FVIIa inhibitor 3-amino-5-[1-[2-({4-[amino(imino)methyl]benzyl}amino)-2-oxo-ethyl]-3-chloro-5-(isopropylamino)-6-oxo-1,6-dihydropyrazin-2-yl]benzoic acid dihydrochloride (PHA-927F) was fully effec-tive in prevention of thrombosis-induced vessel occlusion at a dose of 400 g/kg/min, i.v., in the arterial vasculature (femoral artery). Neither the effective dose nor multiples up to 4.4-fol