MAGIC Ruxolitinib for aGVHD

Inclusion Criteria: * Standard risk cohort: Minnesota standard risk GVHD (except patients with grade I \[\<50% BSA rash\]) * High risk cohort: Minnesota high risk GVHD 3 GVHD that developed after DLI for mixed chimerism or poor graft function is allowed * No prior systemic acute GVHD treatment. Topical or non-absorbed steroids are permitted. * All donor types, HLA-matches, conditioning regimens, or GVHD prophylaxis strategies are acceptable * ≥18 years of age * Standard risk cohort: Hematopoietic engraftment with absolute neutrophil count (ANC) ≥ 1000/μL and platelet count ≥20,000. Use of growth factor supplementation and transfusions to maintain adequate hematologic parameters are allowed. * High risk cohort: Hematopoietic engraftment with ANC ≥ 500/uL and platelet count ≥20,000. Use of growth factor supplementation and transfusions to maintain adequate hematologic parameters are allowed. Exclusion Criteria: * Systemic treatment with ruxolitinib or any other JAK inhibitor within 7 days of study entry * Prior use of ruxolitinib to treat GVHD at any time * Relapsed, progressing or persistent malignancy requiring withdrawal of systemic immunosuppression * Relapse prior to development of GVHD unless subsequently in remission for at least 3 months * GVHD that developed after DLI for relapse is not allowed without study PI or medical monitor approval * Uncontrolled infection (i.e., progressive symptoms related to infection despite treatment or persistently positive microbiological cultures despite treatment or any other evidence of severe sepsis) * Severe organ dysfunction within 3 days of enrollment including requirement for dialysis, mechanical ventilation, continuous BiPAP, or continuous high flow oxygen by nasal cannula, or total bilirubin ≥ 3x upper limit of normal not due to GVHD. * A clinical presentation resembling de novo chronic GVHD or overlap syndrome developing before or present at the time of enrollment (except for mild oral or ocular GVHD) * Corticosteroids \>10 mg/day methylprednisolone (or other methylprednisolone equivalent, MPE) for any indication within 5 days before the onset of acute GVHD except for adrenal insufficiency or premedication for transfusions/IV meds * Participation in clinical trials using experimental agents not approved by the FDA for any indication within 14 days of enrollment or five half-lives, whichever is longer provided any prior adverse events have improved to ≤grade 1 * Patients who are pregnant or nursing * History of allergic reaction to ruxolitinib or any JAK inhibitor