Addition of Cord Blood Tissue-Derived Mesenchymal Stromal Cells to Ruxolitinib for the Treatment of Steroid-Refractory Acute Graft Versus Host Disease

PRIMARY OBJECTIVE: I. To estimate between-arm differences (Arm 3 versus \[vs\] Arm 1, and Arm 2 vs Arm 1) for each of the 28-day co-primary outcome probabilities. OUTLINE: Patients are randomized to 1 of 3 arms. ARM 1: Patients receive ruxolitinib orally (PO) twice daily (BID) for at least 3 days and may consider tapering after 6 months of therapy if response occurs and therapeutic corticosteroid doses have been discontinued. ARM 2: Patients receive ruxolitinib PO BID as in Arm 1. Patients also receive lower dose of cb-MSCs intravenously (IV) for up to 60 minutes twice weekly (at least 3 days apart) over 4 consecutive weeks for 8 total doses. ARM 3: Patients receive ruxolitinib PO BID as in Arm 1. Patients also receive higher dose of cb-MSCs IV for up to 60 minutes twice weekly (at least 3 days apart) over 4 consecutive weeks for 8 total doses. After completion of study treatment, patients are followed up on day 28 and then for up to 6 months.