Researchers today presented and published results from the TRA-2P ( Thrombin- Receptor Antagonist in Secondary Prevention of Atherothrombotic Ischemic Events) TIMI 50 study of vorapaxar, Merck's investigational anti-thrombotic medicine, in patients with a prior history of cardiovascular events or disease. In the study, the addition of vorapaxar to standard of care (e.g. 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. 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. There was also a significant increase in bleeding, including intracranial hemorrhage (ICH), among patients taking vorapaxar in addition to standard of care, although the risk of ICH was lower in patients without a history of stroke. The results of TRA-2P in 26,449 patients were presented during a late-breaking clinical trials session at the American College of Cardiology 61 st Annual Scientific Session (ACC.12) and published concurrently online in the New England Journal of Medicine. The study was led by the Thrombolysis In Myocardial Infarction (TIMI) Study Group of Brigham and Women's Hospital in Boston, Massachusetts. In this three-year study, the addition of vorapaxar to standard of care in the full study population significantly reduced the risk of the protocol-specified primary composite endpoint of cardiovascular death, heart attack, stroke or urgent coronary revascularization by 12 percent compared to placebo plus standard of care (11.2 percent vs. 12.4 percent, p=0.001). The addition of vorapaxar also resulted in a significant 13 percent reduction in the protocol-specified key secondary composite endpoint of CV death, heart attack and stroke (9.3 percent vs. 10.5 percent, p<0.001). The addition of vorapaxar significantly increased moderate or severe bleeding, as measured by the GUSTO scale 1, (4.2 percent vs. 2.5 percent, p<0.001). There was no statistically significant difference in the rate of fatal bleeding in the study between the group receiving vorapaxar and the group receiving standard of care alone (0.3 percent vs. 0.2 percent, p=0.19). Rates of intracranial hemorrhage (ICH) were significantly greater in the vorapaxar arm compared to placebo (1.0 percent vs. 0.5 percent, p<0.001), primarily driven by patients with a history of stroke. In patients without a history of stroke, the rates of ICH were numerically greater in the vorapaxar arm compared to placebo (0.6 percent vs. 0.4 percent p=0.049). "Results from this trial demonstrated for the first time that inhibition of another platelet pathway in addition to standard antiplatelet therapy reduced the risk of recurrent cardiovascular events in long-term secondary prevention,” said David A. Morrow, M.D., MPH, senior investigator at the TIMI Study Group and Director, Levine Cardiac Intensive Care Unit, Brigham and Women's Hospital. "As is the case with other potent oral antiplatelet agents, the antithrombotic benefit of vorapaxar must be weighed against the increased risk of bleeding, and any potential clinical use of vorapaxar would have to be based on appropriate patient selection."