The first human stem-cell based drug failed two late-stage clinical trials, reports the New York Times. The drug, Prochymal, from Osiris Therapeutics was made from mesenchymal stem cells from healthy young adults and was found to be no more effective than placebo in treating graft-versus-host disease. Prochymal did, however, appear to have an effect in a subset of patients. "Prochymal is having a clear effect in the liver, and that is the most underserved patient population," CEO C.