Prochymal Expanded Access Treatment for Pediatric Patients Who Have Failed Steroids for Acute GVHD

For the treatment of pediatric patients who have failed to respond to steroid treatment for
acute graft-versus-host disease (GVHD). Failing steroid treatment for acute GVHD is defined
as any Grade B-D (IBMTR grading) of acute GVHD that is not improving after at least 3 days of
methylprednisolone (≥ 1 mg/kg/day) or equivalent.

Patients will be treated with Prochymal twice per week at a dose of 2 x 10^6 hMSC/kg (actual
body weight) for each of 4 consecutive weeks. Infusions will be administered at least 3 days
apart.

Inclusion Criteria:

- Patients must be 2 months to 17 years of age, inclusive

- Patients who have failed to respond to steroid treatment for Grades B-D acute GVHD

- Patient must not have a known allergy to bovine or porcine products

- Patient must not have received a transplant for a solid tumor disease.

- Patient must not have evidence of a pulmonary infiltrate or diffuse alveolar
hemorrhage and is likely to require more than 2L of oxygen via face mask or an
estimated FiO2 of 28% via other delivery methods in order to sustain an O2 saturation
of 92% during the next 3 days.