Osiris shares blitzed after pivotal Prochymal trials fail

In a major setback, Osiris Therapeutics announced this morning that preliminary results indicate that its stem cell therapy Prochymal failed both of its late-stage clinical trials. One analyst swiftly dubbed the preliminary results "horrible," and shares of the company swiftly plunged 52 percent.

In one of the studies for steroid refractory graft-versus-host-disease, 35 percent of the patients in the Prochymal arm responded to the therapy, versus 30 percent of the placebo group. And in a second study for first-line GVHD patients, the placebo response rate (46 percent) actually edged out the Prochymal response rate (45 percent). "The response rate data from the two Prochymal studies are horrible," notes TheStreet's Adam Feuerstein, "despite Osiris' attempts a data-mining for something positive to say."

For its part, Osiris highlighted significant response rates for children and steroid-refractory gastrointestinal GvHD."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," Chief Executive Randal Mills said in a statement.

- read the Osiris release
- read the report from TheStreet
- check out the Reuters report