Study Testing Two Conditioning Regimen With a Single Prophylaxis of GVHD by Cyclophosphamide and Methotrexate Post-transplant in Patients Eligible for Matched-donor Allograft Transplantation

Inclusion Criteria: * Age: ≥ 18 and ≤ 70 years old * Patient with hematologic malignancy * Indication for HSC allograft with attenuated conditioning * Pluripotent stem cell (PSC) engraftment * Availability of a 10/10 familial or non-familial HLA compatible donor * Consent to the protocol * ECOG \<=2 * Woman of childbearing age with negative pregnancy test and on highly effective contraception during treatment and for a period of 12 months after stopping MTX and CY * Man of childbearing age with highly effective contraception during treatment and for a period of 6 months after stopping MTX and CY and a period of 12 months after stopping MTX and CY if TBF conditioning regimen arm * Negative Hepatitis B, C, HIV serologies * Social security affiliation Exclusion Criteria: * History of allograft * Patient eligible for myeloablative conditioning (MAC) * Bone marrow transplant * Other progressive cancerous disease, or antecedent of cancer in the last five years, with the exception of a carcinoma of the skin or a carcinoma in situ of the uterine cole treated and in remission. * Progressive psychiatric condition * Pregnant or breastfeeding woman, * Woman or man of childbearing age with lack of effective contraception * Serious and uncontrolled concomitant infection * Cardiac: systolic ejection fraction \< 50% by transthoracic ultrasound or by isotopic method (isotope gamma angiography), NYHA II, III or IV heart failure, active rhythmic, valvular or ischemic heart disease or anteriority * Respiratory with EFR: DLCOc \<40% of theoretical * Renal: creatinine clearance \< 50 ml/min (assessment with MDRD method) * Urological: active urinary tract infection, history of acute urothelial toxicity due to cytotoxic chemotherapy or radiotherapy, known obstruction of urinary flow, pre-existing hemorrhagic cystitis * Hepatic: transaminases greater than 5 times normal or bilirubin greater than 2 times normal * Person protected by law (major under guardianship, curatorship or legal protection) * Vaccination against yellow fever in the last year * Known or suspected hypersensitivity to rabbit proteins as well as to the active substance and excipients of all investigational and ancillary drugs administered during the study, * Contraindication to any of the investigational or adjuvant drugs administered during the study * Patient not speaking French