Osiris Therapeutics announces interim one-year results of Prochymal trial Osiris Therapeutics announced interim one-year results from its groundbreaking clinical trial evaluating Prochymal for the treatment of patients experiencing first-time acute myocardial infarction. 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. Patients treated with Prochymal also experienced significantly less stress-induced ventricular arrhythmia. 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. The mechanistic data is complemented by clinical data showing treatment with Prochymal resulted in a statistically significant reduction in heart failure. The trial also demonstrated that treatment with Prochymal was safe. There were no infusional toxicities observed in patients receiving Prochymal. Serious adverse events occurred with equal frequency in both treatment groups at 31.8%. To date, there have been 5 deaths in the trial, 2 in the Prochymal group and 3 in the placebo group.