HCT With PTCy in Higher-risk MDS

Inclusion Criteria: * MDS defined by WHO classification, CMML, or AML evolving from MDS A. International Prognostic Scoring System (IPSS) \> 1.0 or bone marrow blast ≥ 5% at any time points before HCT or B. AML progressed from MDS or C. CMML with bone marrow blast ≥ 5% at any time points before HCT * 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 , under 75 years * Adequate performance status (Karnofsky score of 70 or more) * Adequate hepatic function (AST or ALT \< 3 x upper normal limits and bilirubin \< 1.5 x upper normal limit). * Adequate renal function (creatinine \< 2.0 mg/dL or creatinine clearance ≥ 50 mL/min) * Adequate cardiac function (left ventricular ejection fraction ≥ 50% on heart scan or echocardiogram) * Adequate pulmonary function: DLCO, FEV1, and FVC ≥ 45% predicted by pulmonary function tests * 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) * Presence of contraindications to cyclophosphamide (patients receiving pentostatin, symptomatic cystitis, urinary tract obstruction, with a history of hypersensitivity reactions to the component of the drug)