- Participants must have steroid-refractory cGVHD. Steroid-refractory cGVHD is defined as having persistent signs and symptoms of cGVHD (Appendix D; section 17.4) despite the use of prednisone at ≥ 0.25 mg/kg/day (or 0.5 mg/kg every other day) for at least 4 weeks (or equivalent dosing of alternate corticosteroids) without complete resolution of signs and symptoms. Patients with either extensive chronic GVHD or limited chronic GVHD requiring systemic therapy are eligible.