• Recipient of allogeneic hematopoietic stem cell transplantation

• Participants must have steroid-refractory cGVHD and had obtained any response other than progression after at least 12 weeks of treatment with ruxolitinib. Steroid-refractory cGVHD is defined as having persistent signs and symptoms of cGVHD 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.

• Stable dose of glucocorticoids for 4 weeks prior to enrollment.

• No addition or subtraction of other immunosuppressive medications (e.g., calcineurin-inhibitors, sirolimus, mycophenolate-mofetil) for 4 weeks prior to enrollment. The dose of immunosuppressive medicines may be adjusted based on the therapeutic range of that drug.

• No age limit. In the case of children participating in the study, the informed consent will be signed by a parents or legal guardians.

• Eastern Cooperative Oncology Group scale performance status 0-2

• Participants must have adequate organ function

• Women of child-bearing potential and men must agree to use adequate contraception (hormonal or barrier method of birth control; abstinence) prior to study entry and for the duration of study participation. Should a woman become pregnant or suspect she is pregnant while participating in this study, she should inform her treating physician immediately.

• Ability to understand and the willingness to sign a written informed consent document