This is an open-label, Phase 2 study designed to evaluate the safety and efficacy of belumosudil and rituximab as primary treatment of cGVHD.

Inclusion Criteria:

• First episode of systemic immunosuppression-requiring cGVHD, defined as classic cGVHD by the NIH consensus criteria (without features or characteristics of aGVHD)
• Previously untreated, defined by having received <10 days of corticosteroids or alternative systemic immunosuppressive agent started specifically for a new diagnosis of cGVHD
• KPS >/= 70%
• Adequate hematologic function independent of platelet transfusion and G-CSF for at least 7 days prior to study entry: ANC >750 cells/mm3; Platelets >30,000 cells/mm#

Exclusion Criteria:

• Late persistent or recurrent aGVHD
• Active uncontrolled infection
• History of HIV infection
• Active HBV or HCV infection. Subjects who are positive for hepatitis B core antibody, hepatitis B surface antigen, or hepatitis C antibody must have a negative PCR result before enrollment. Those who are PCR positive will be excluded.
• Calculated CrCl <30mL/min
• AST and/or ALT >5x ULN or direct bilirubin >3x ULN
• Cardiac ejection fraction <40% or history of uncontrolled cardiac arrhythmias
• Has received more than one allogeneic transplant prior to the occurrence of cGVHD