Study shows vorapaxar reduces cardiovascular events, but raises bleeding worries

Confirming earlier mixed top-line results, US drug giant Merck & Co (NYSE: MRK; The Pharma Letter February 8) presented results from the TRA-2P (Thrombin-Receptor Antagonist in Secondary Prevention of Atherothrombotic Ischemic Events) TIMI 50 study of vorapaxar, its investigational anti-thrombotic drug, in patients with a prior history of cardiovascular events or disease.

In the study, the addition of vorapaxar to standard of care (eg, aspirin, or thienopyridine or both) resulted in a significantly greater reduction in the risk of the composite of cardiovascular (CV) death, heart attack, stroke or urgent coronary revascularization. However, treatment with vorapaxar also led to worrying adverse effects of moderate or severe bleeding, as well as an excess of intracranial hemorrhage, in all treated patients, raising concerns about the drug’s safety.

This is the first time that an anti-thrombotic medicine added to the standard of care, including aspirin, has been shown to provide an additional, significant reduction in cardiovascular events in the secondary prevention setting, defined as patients who previously experienced a heart attack, an ischemic stroke, or who had documented peripheral arterial disease, or PAD, said researchers presenting the TRA-2P study results in 26,449 patients at the American College of Cardiology 61st Annual Scientific Session over the weekend. The study was led by TIMI Study Group of Brigham and Women's Hospital in Boston, Massachusetts.