Prochymal® Expanded Access for Adults Who Have Failed Steroid Treatment for Acute Graft Versus Host Disease (GVHD)

Inclusion Criteria: * Patients must be 18 years to 70 years of age, inclusive. * Biopsy confirmation of GVHD is strongly recommended, to exclude patients presenting with diarrhea or abnormal liver function tests caused by infection. * Patients must have failed to respond to steroid treatment (methylprednisolone \[≥1mg/kg/day\] or equivalent) for Grades C-D acute GVHD. * Prochymal must be administered not longer than 14 days after the initiation of systemic steroid therapy for acute GVHD. * Prochymal must be administered either before or at the same time any additional GVHD therapy is administered * Patients must have an adequate renal function as defined by Cockcroft-Gault equation:Calculated creatinine clearance (CrCl) \> 30 mL/min * Patients who are women of childbearing potential, must be non-pregnant, not breast-feeding, and use adequate contraception. Male patients must use adequate contraception. Exclusion Criteria: * Patient has stage 3 or 4 liver GVHD, bilirubin \>6 mg/dl. * Patient has stage 4 GI-GVHD. * Patient has any underlying or current medical condition that would interfere with the evaluation of the patient including uncontrolled infection, sepsis, organ failure, etc or any medical condition that has a high probability of causing death in less than 30 days. * Patient may not receive any other investigational agent (not approved by the FDA for any indication) concurrently for the duration of the protocol. * Patient has evidence of a pulmonary infiltrate or diffuse alveolar hemorrhage and must not be likely to require more than 2 liters of oxygen via face mask or an estimated fractional inspired oxygen concentration (FiO2) of 28% via other delivery methods in order to sustain an O2 saturation of 92% during the next 3 days. * Patient has a known allergy to bovine or porcine products * Patient has a medical history of a solid tumor disease.