A Novel Inhibitor of Protease-activated Receptor 1: A Review of Chemical Structure and Mode of Action.

Limitations of current antiplatelet therapies have led to the discovery of new antiplatelet agents with new modes of action. Vorapaxar has been developed as a thrombin receptor antagonist. This drug works against the protease-activated receptor 1 (PAR1) and inhibits platelet aggregation mediated by PAR1. This article reviews this new class of antiplatelet therapy in detail with an acute focus on the TRACER (Thrombin Receptor Antagonist for Clinical Event Reduction in Acute Coronary Syndrome) and TRA 2°P-TIMI 50 (Trial to Assess the Effects of Vorapaxar in Preventing Heart Attack and Stroke in Patients With Atherosclerosis-Thrombolysis In Myocardial Infarction 50) trials. Vorapaxar has proven to be beneficial when administered to stable atherosclerotic patients. However, it has been shown to increase risk of intracranial hemorrhage in patients with known, previous history of cerebrovascular incidence. Despite these limitations, TRA 2°P-TIMI 50 results showed that vorapaxar appears to have a definitive therapeutic benefit when administered alongside aspirin or when it is used as an addition to dual antiplatelet therapy for patients with stable atherosclerosis.