GRAVITAS-119: Itacitinib in Combination With Calcineurin Inhibitor-Based Interventions for the Prophylaxis of Graft-Versus Host Disease

Inclusion Criteria: * Subjects with acute leukemia, chronic myelogenous leukemia, or myelodysplasia with no circulating blasts and \< 5% blasts in the bone marrow. * Subjects with non-Hodgkin lymphoma, including but not limited to chronic lymphocytic leukemia/small lymphocytic lymphoma, follicular, marginal zone, diffuse large B cell, or mantle cell lymphoma must have chemosensitive disease at time of transplant. Subjects with Hodgkin lymphoma with chemosensitive disease at the time of transplant. * Must be candidates for reduced-intensity conditioning regimens. * Must be candidates for peripheral blood stem cell transplants. * Karnofsky Performance Status score ≥ 70% or Eastern Cooperative Oncology Group Performance Status score of 0 to 2. * Serum creatinine ≤ 2.0 mg/dL or creatinine clearance ≥ 40 mL/min measured or calculated by Cockcroft-Gault equation. * Be willing to avoid pregnancy or fathering children. Exclusion Criteria: * Has previously received an allogenic hematopoietic stem cell transplant. * Presence of an active uncontrolled infection. * Known HIV infection. * Active hepatitis B virus (HBV) or hepatitis C virus (HCV) infection that requires treatment or at risk for HBV reactivation. * Prior malignancies. * Severe organ dysfunction. * Prior treatment with a JAK inhibitor or with an investigational agent, device, or procedure within 21 days of enrollment. * Currently breastfeeding. * Known allergies, hypersensitivity, or intolerance to any of the study medications. * Receipt of live (including attenuated) vaccines during the study, or anticipation of need for such a vaccine during the study. * History of primary idiopathic myelofibrosis or any severe marrow fibrosis that would prolong neutrophil engraftment to \> 28 days after transplant. * Post-transplant maintenance therapy for the hematologic malignancy or plans to initiate maintenance therapy during study treatment.