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