- Suitable candidates are patients with classic chronic GVHD or overlap syndrome (classic chronic plus acute GVHD)that is: a)Previously untreated (newly diagnosed) as defined by having received < 14 days of prednisone (or equivalent) before enrollment/randomization to study therapy; b)Previously treated but inadequately responding after ≤ 16 weeks of initial therapy with prednisone and/or calcineurin inhibitor (CNI) ± additional non-sirolimus agent (started at the time of chronic GVHD diagnosis).