Osiris Therapeutics Declares Preliminary Results For Prochymal Phase III GvHD Trials

Osiris Therapeutics has announced preliminary results for two phase III trials evaluating Prochymal for the treatment of acute graft versus host disease (GvHD). Prochymal showed significant improvements in response rates in difficult-to-treat liver and gastrointestinal GvHD, however neither trial reached its primary endpoint.

Randal Mills, president and chief executive officer of Osiris Therapeutics, said: “These data are still preliminary and further analysis is needed to gain a full appreciation of the results of these rigorous, double-blind, placebo-controlled trials. We are encouraged to see Prochymal significantly improve response rates above standard of care in GvHD patients who currently have no good treatment options. We will meet with the FDA as soon as possible to discuss the most appropriate and efficient path forward for Prochymal in this life-threatening indication.”

Protocol 265 was designed to evaluate Prochymal as a first-line agent for the treatment of acute GvHD in combination with steroid therapy. The majority of patients in this trial were suffering from skin GvHD, which responded significantly better to steroids than had been previously reported in controlled trials. This high response rate to standard of care diminished the potential for Prochymal to demonstrate an effect.

Based upon the results of the steroid-refractory GvHD trial, Osiris plans to file an amendment with the FDA to the current expanded access program..