- Participants must have steroid-refractory cGVHD despite use of 2 or more agents. Steroid-refractory cGVHD is defined as having persistent signs and symptoms of cGVHD (Appendix C, D) 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 glucocorticoids) without complete resolution of signs and symptoms. Participants with either extensive or limited chronic GVHD requiring systemic therapy are eligible.