Trial of GVHD Prophylasxis With PTCy or Thymoglobulin in Unrelated SCT

Inclusion Criteria: * Patients must have an indication for allogeneic hematopoietic stem cell transplantation * Diagnosis: Chronic myeloid leukemia Myelodysplastic Syndromes Myeloprolipherative neoplsm unclassified Atypical chronic myelogenous leukemia * Signed informed consent * Patients with 10/10 HLA-matched unrelated donor available. The donor and recipient must be identical by the following genetic loci: HLA-A, HLA-B, HLA-Cw, HLA-DRB1, and HLA-DQB1. Mismatches in these loci are not allowed. * Peripheral blood stem cells as graft source * No second tumors * No prior history of Thymoglobulin exposure or no history of anaphylactic shock after Thymoglobulin administration * No severe concurrent illness Exclusion Criteria: * Moderate or severe cardiac dysfunction, left ventricular ejection fraction \<50% * Moderate or severe decrease in pulmonary function, FEV1 \<70% or DLCO\<70% of predicted * Respiratory distress \>grade I * Severe organ dysfunction: AST or ALT \>5 upper normal limits, bilirubin \>1.5 upper normal limits, creatinine \>2 upper normal limits * Creatinine clearance \< 60 mL/min * Uncontrolled bacterial or fungal infection at the time of enrollment * Requirement for vasopressor support at the time of enrollment * Karnofsky index \<30% * Pregnancy * Somatic or psychiatric disorder making the patient unable to sign informed consent