Prochymal Significantly Reduces Hypertrophy, Arrhythmia and Progression to Heart Failure in Patients Suffering a Heart Attack

Osiris Therapeutics, Inc. OSIR, announced today interim one-year results from its groundbreaking clinical trial evaluating Prochymal® (remestemcel-L) for the treatment of patients experiencing first-time acute myocardial infarction. The trial is the largest study of allogeneic or "off-the-shelf" stem cells ever conducted in heart attack patients. A total of 220 patients were given a single infusion of either Prochymal or placebo through a standard intravenous line within seven days of an acute heart attack. Cardiac MRI assessments were conducted for six months following infarct to evaluate cardiac remodeling. Patients receiving Prochymal had significantly less cardiac hypertrophy, as measured by cardiac MRI, compared to patients receiving placebo (p<0.05). Patients treated with Prochymal also experienced significantly less stress-induced ventricular arrhythmia (p<0.05). Cardiac hypertrophy and ventricular arrhythmia are indicators of pathological remodeling following heart injury and provide insight into the mechanism by which mesenchymal stem cells attenuate heart injury following a myocardial infarction.