Osiris Therapeutics, Inc. (NASDAQ: OSIR), announced that it has successfully completed enrollment in a Phase 2 clinical trial evaluating Prochymal (remestemcel-L), an adult mesenchymal stem cell therapy, in patients experiencing their first heart attack. The double-blind, placebo-controlled trial enrolled a total of 220 patients from 33 leading clinical centers in the United States and Canada.

"We appreciate the participation of our outstanding team of clinicians and would like to offer our special thanks to the patients who are taking part in this exciting trial," said Lode Debrabandere, Ph.D., Senior Vice President of Therapeutics at Osiris. "We look forward to following their progress and collecting high quality data on the safety and efficacy of Prochymal in this significant indication."

In 2009, Osiris completed a Phase 1 double-blind, placebo-controlled study in 53 patients that demonstrated the safety of Prochymal in cardiac patients suffering from their first heart attack. Additionally, treatment with Prochymal significantly improved cardiac function, patient global assessment and reduced cardiac arrhythmias (irregular heartbeat) when compared to placebo.

About the Phase 2 Acute Myocardial Infarction Trial

The Phase 2 double-blind, placebo-controlled trial will evaluate the safety and efficacy of Prochymal in conjunction with standard of care in improving heart function in patients who experienced their first heart attack. The trial is being conducted at leading institutions and academic research centers in the United States and Canada. The focus is on patients who have suffered a severe myocardial infarction. To be classified as severe, the patient's left ventricular ejection fraction, or LVEF, must have been between 20% and 45% at baseline. LVEF, which reflects the fraction of blood pumped out of a ventricle with each heart beat, is a common measurement of overall heart function and typically declines after a heart attack. Patients were randomized to either Prochymal or placebo at 1:1. Efficacy endpoints determined from cardiac MRI include end systolic volume, LVEF and the ability of Prochymal to preserve functional heart tissue and limit scar formation following a heart attack. In addition, functional and quality of life assessments will be performed.