Anti-NKG2A Monoclonal Antibody for AML or MDS Patients Undergoing Haploidentical Transplantation

Inclusion Criteria: 1. Patients capable of providing informed consent according to ICH/ GCP, and national/local regulations and be willing to comply with all study-related procedures. 2. Adult patients aged ≥18 years old, without any restriction of gender and race. 3. Patients with a hematologic malignancy represented either by Acute Myeloid Leukemia (AML) or Myelodysplastic Syndrome (MDS) or Myelodysplastic syndrome/Myeloproliferative neoplasm (MDS/MPN). 4. Patients lacking a HLA identical donor and receiving haploidentical stem cell transplant with GVHD/HVG prophylaxis consisting of Cyclophosphamide: 40 or 50 mg/kg/day, day +3 and +4, Cyclosporine A: 3 mg/kg/day from day +5, Mycophenolate mofetil: 45 mg/kg/day, from day +5 to day +35. 5. Patient who has received haplo-SCT with a myeloablative or reduced intensity or nonmyeloblative conditioning followed, either by a bone marrow or a peripheral blood stem cell (PBSC) graft. 6. Negative beta-human chorionic gonadotropin (β-HCG) pregnancy test within 8 days prior to start of study drug for women of childbearing potential. 7. Women of childbearing potential must agree to use a highly effective method of contraception from the time of giving informed consent until at least 52 weeks after the last dose of study therapy. Men with female partners who are of childbearing potential must agree that they will use a highly effective method of contraception from the time of giving informed consent until at least 52 weeks after the patient receives his last dose of study therapy contraception. Exclusion Criteria: 1. Patients aged \< 18 years old. 2. Active uncontrolled infections. 3. CNS involvement of AML disease. 4. Karnofsky performance status (KPS) \<60% or severe organ dysfunction, including a left ventricular ejection fraction \<40%, DLCO \<50% or creatinine clearance \<50 ml/min (as per transplant eligibility). 5. Pregnant or breast-feeding or intending to become pregnant during the study. 6. Patients who rapidly relapse after allogenic-SCT before day 30 after allogenic-SCT. 7. Patients who experience acute GVHD before day +30 after allogenic-SCT. 8. Patients treated with a second allogeneic Allo-SCT.