Hematopoietic Cell Transplantation With Post-transplantation Cyclophosphamide in MDS

Inclusion Criteria: * MDS defined by WHO classification, chronic myelomonocytic leukemia (CMML), or acute myeloid leukemia (AML) evolving from MDS A. IPSS \> 1.0 or bone marrow blast ≥ 5% at any time points before HCT or B. AML progressed from MDS or C. CMML * Patients receiving first HCT * Patients with appropriate hematopoietic cell donors A. HLA-matched sibling donor B. Unrelated donor C. HLA-mismatched familial donor * 15 years old or older * Adequate performance status (Karnofsky score of 70 or more) * Adequate hepatic and renal function (AST, ALT, and bilirubin \< 3.0 x upper normal limit, and creatinine \< 2.0 mg/dL). * Adequate cardiac function (left ventricular ejection fraction over 40% on heart scan or echocardiogram * Signed and dated informed consent must be obtained from both recipient and donor. Exclusion Criteria: * Presence of significant active infection * Presence of uncontrolled bleeding * Any coexisting major illness or organ failure * Patients with psychiatric disorder or mental deficiency severe as to make compliance with the treatment unlike, and making informed consent impossible * Nursing women, pregnant women, women of childbearing potential who do not want adequate contraception * Patients with a diagnosis of prior malignancy unless disease-free for at least 5 years following therapy with curative intent (except curatively treated nonmelanoma skin cancer, in situ carcinoma, or cervical intraepithelial neoplasia)