Decision Makes Investigational Stem Cell Treatment Available to Critically Ill Children

Osiris Therapeutics, Inc. (NASDAQ:OSIR) today announced it has been given clearance by the U.S. Food and Drug Administration (FDA) to initiate an expanded access treatment program for Prochymal, making the investigational stem cell product available to children with life-threatening Graft vs. Host Disease (GvHD). Prochymal, a formulation of adult mesenchymal stem cells administered through a standard intravenous line, is currently in Phase III clinical trials, the final stage of clinical testing before submission to FDA for marketing approval.

Congress and FDA created the expanded access program to facilitate the availability of promising new drugs to desperately ill patients before general marketing begins. The program allows for investigational drugs to be made available to patients under certain circumstances during evaluation in late stage clinical trials when no satisfactory alternative therapy is available. For expanded access, FDA must determine that the available scientific evidence, taken as a whole, demonstrates that the drug may be effective for its intended use or would not expose the patients to unreasonable and significant additional risk of illness or injury. Additionally, FDA permits companies meeting certain criteria to charge for the investigational product.

"Prochymal has had a profound positive impact on the children that we have treated, all of whom had exhausted available therapeutic options," said Paul Szabolcs, M.D., Pediatric Blood and Marrow Transplant Program at Duke University. "Since there are no approved treatments for GvHD and mortality is so high, gaining faster and more reliable access to Prochymal will be very helpful to the families we serve."

GvHD is a life-threatening immune reaction that can occur in patients following bone marrow transplantation. Steroids are typically used to control the disease, however they are often ineffective. In patients that fail to respond to steroids, mortality can reach 85%.

In support of the expanded access treatment program, Osiris submitted summary safety and efficacy data to FDA. Prochymal was evaluated in pediatric patients suffering from severe GvHD that had failed, on average, three lines of therapy prior to entry into the trial. All patients (12 of 12) experienced an objective clinical response to therapy, and 58% achieved complete resolution of their GvHD. In a Phase II randomized, prospective trial evaluating Prochymal for acute GvHD in adults, 94% (29 of 31) responded after receiving two infusions of Prochymal, with 74% achieving complete resolution of their disease. There were no infusional toxicities associated with the administration of Prochymal in either trial.

“More kids' lives will be saved thanks to adult stem cells and the FDA’s prompt action,” said U.S.