Merck announced the completion of patient enrolment in the TRA 2°P-TIMI 50 clinical trial, a phase-III, randomized, double-blind, placebo-controlled, multinational study of SCH 530348, the company's investigational antiplatelet protease activated receptor-1 (PAR-1) inhibitor. The study, conducted by the Thrombolysis in Myocardial Infarction (TIMI) Study Group, reached its target of more than 26,000 patients.

"TIMI 50 is the largest and most rapidly enrolling trial in our 25-year history," commented Eugene Braunwald, chairman of the TIMI Study Group. "We are very pleased with this achievement and look forward to completing this important clinical outcome trial," he added.

The trial will assess the ability of SCH 530348, a thrombin receptor antagonist, or PAR-1 inhibitor, to prevent major cardiovascular events when added to current antiplatelet regimens (aspirin or aspirin + ADP inhibitor) in patients who have previously experienced a heart attack or stroke or who have peripheral arterial disease.

SCH 530348 is also being studied in the treatment of patients with acute coronary syndrome (ACS) in the ongoing Thrombin Receptor Antagonist for Clinical Event Reduction in Acute Coronary Syndrome (TRA-CER) trial, led by Duke Clinical Research Institute.

"The completion of enrollment in one of our two pivotal clinical outcome trials for this investigational medicine is a significant milestone achievement in the development of SCH 530348," said Luciano Rossetti, senior vice president and head, Global Scientific Strategy, Merck Research Laboratories. "Heart disease remains the leading cause of death worldwide, and we believe that this novel agent has the potential to address a significant unmet medical need," he added.

Approximately 7.2 million people worldwide die each year from coronary heart disease, the most common cause of death in Europe and the United States. In spite of advances in antiplatelet and other preventive treatments, there remains a residual risk for further cardiovascular events in patients with established vascular disease.

The investigational antiplatelet SCH 530348 is being developed by Merck for the prevention and treatment of atherothrombotic events in patients with acute coronary syndrome and in those with prior myocardial infarction or stroke, as well as in patients with existing peripheral arterial disease.