Thrombin-receptor antagonist increases bleeding in patients with ACS

Abstract

Vorapaxar, a first-in-class, oral antagonist of protease-activated receptor 1 (PAR-1), inhibits thrombin-induced platelet activation, but failed to reduce the primary efficacy end point, and increased bleeding compared with standard therapy in patients with non-ST-segment elevation acute coronary syndromes (NSTE-ACS). “Earlier phase II studies in percutaneous coronary intervention (PCI) and ACS patients showed that vorapaxar did not increase the risk of bleeding, and had a trend towards reducing myocardial infarctions,” says Dr. Pierluigi Tricoci from the Duke Clinical Research Institute, NC, USA. However, Dr. Udaya Tantry from the Sinai Cener for Thrombosis Research, MD, USA thinks “the vorapaxar phase II trials actually did not reveal much information regarding safety or efficacy, since they were of too short duration and underpowered.” Therefore, says Dr. Tricoci, “two large phase III trials with long-term follow up were designed to confirm the preliminary findings.”