Itacitinib With High-dose Posttransplantation Cyclophosphamide in Older Patients

Inclusion Criteria: Presence of a suitable related, HLA-haploidentical (partially mismatched) stem cell donor. Eligible diagnoses: Acute leukemias in complete remission with minimal residual disease Myelodysplastic syndrome (MDS) with at least one poor-risk feature Chronic myelomonocytic leukemia with at least one poor-risk feature T-cell PLL in PR or better prior to transplantation. Tyrosine kinase-refractory CML in first chronic phase, TKI-intolerant CML in first chronic phase, or CML in second or subsequent chronic phase. Philadelphia chromosome negative myeloproliferative disease (including myelofibrosis) Multiple myeloma or plasma cell leukemia with a PR or better to the last treatment regimen Age ≥ 60 years. Adequate end-organ function as measured by: Left ventricular ejection fraction ≥ 35% or shortening fraction > 25% Bilirubin ≤ 3.0 mg/dL (unless due to Gilbert's syndrome or hemolysis), and ALT and AST ≤ 5 x ULN FEV1 and FVC ≥ 40% of predicted ECOG performance status ≤ 2 or Karnofsky score ≥ 60 Exclusion Criteria: No active extramedullary leukemia or known active CNS involvement by malignancy. Any previous autologous HSCT must have occurred at least 3 months prior to start of conditioning. No previous allogeneic HSCT. Not pregnant or breast-feeding No uncontrolled infection. No known HIV infection. No active replicating HBV or HCV infection detected by PCR that requires treatment or at risk for HBV reactivation (positive HBsAg)