Post Transplant Cyclophosphamide in Matched Unrelated Donor Stem Cell Transplantation for Hematological Malignancies

Inclusion Criteria: * Men and Women of Any Age * Indication for an HSCT without matched sibling donor * Have a matched unrelated donor (HLA 10 x 10 or 9 x 10) * Hematological malignancy Exclusion Criteria: * Acute leukemias not in complete response (that is \> 5% blast in the bone marrow) * Chemorefractory lymphoproliferative disease * Active uncontrolled infection * HCT-CI \> 3 * Severe organic disfunction (heart ejection fraction \< 45%, glomerular filtration rate \< 50 mL.hour, pulmonary DLCO \< 50%) * Previous allogeneic bone marrow transplantation * Contraindication to cyclophosphamide or ATG