Efficacy Study of Anti-KIR Monoclonal Antibody as Maintenance Treatment in Acute Myeloid Leukemia (EFFIKIR)

Inclusion Criteria: 1. Primary or secondary Acute Myeloid Leukemia (AML, defined according to WHO 2008 criteria), in first CR/CRi (according to the revised recommendations of the International Working Group for Diagnosis, Standardization of Response Criteria, Treatment Outcomes, and Reporting Standards for Therapeutic Trials in Acute Myeloid Leukemia J Clin Oncol. 2003 Dec 15; 21(24):4642-9 see appendix 19.3) following induction chemotherapy and who received 1 or 2 consolidation cycles. Induction chemotherapy should be performed within 6 months before randomization. Consolidation cycle is defined as any chemotherapy administered within 3 months following CR and including aracytine irrespective of the administered dose(s). A minimum of one and maximum of 2 cycles should be administered before enrollment 2. Patients not eligible for an allogeneic hematopoietic cell transplantation 3. Age 60 to 80 4. ECOG Performance status of 0 or 1 5. Clinical laboratory values at screening * Calculated creatinine clearance (according to MDRD) \> 60 ml/min/1.73 m2 * Platelet \> 75 x 109/l * Hemoglobin ≥ 10 g/dl supported or unsupported by transfusions * ANC \> 1 x 109/l * Total Bilirubin levels ≤ 1.5 ULN * ALT and AST ≤ 3 ULN 6. Recovery from acute toxicity of previous anti-tumor therapy 7. Male patients who accept and are able to use contraception methods recognized as highly effective. 8. Signed informed consent prior to any protocol specific procedure. Exclusion Criteria: 1. Acute Promyelocytic Leukemia with t (15; 17), or its molecular equivalents (PML-RARA) 2. Favorable risk AML corresponding defined as t(8;21) or inv (16) and t(16;16) and their molecular equivalents (AML-ETO and CBFB-MYH11) 3. Last consolidation completed more than 3 months prior to first dosing 4. Concomitant treatment by chemotherapy, immunotherapy or by systemic corticosteroids 5. Within 28 days prior to first dosing: chemotherapy or systemic corticosteroid treatment 6. History of allogeneic hematopoietic cell transplantation or solid organ transplantation 7. History of high dose chemotherapy with autologous hematopoietic transplantation performed as treatment for AML 8. Use of any investigational agent within 2 months prior to the first dosing 9. Use of growth factors (G- or GM-CSF or EPO) within 28 days prior to first dosing 10. Any irradiation within the last 3 months except for analgesic intent 11. Intermittent or continuous renal replacement therapy 12. Abnormal cardiac status with any of the following * Ejection fraction (measured by ultra-sound or radionuclide imaging) \<50% * Myocardial infarction within the previous 6 months * QTc ≥ 480 ms (Bazett's). 13. Current active infectious disease or positive serology for HIV, and/or HCV with detectable viremia and/ or HBV with positive Hbs Antigen and/or negative anti Hbs Antibody 14. Auto-immune disease: * Which currently or previously required systemic immunosuppressive or immuno-modulatory therapy (including corticosteroids administered by systemic route) * And/or has substantial probability to cause an irreversible injury to any tissue * And/or is recent or unstable or has substantial risk to progress and cause severe complications. 15. Serious concurrent uncontrolled medical disorder 16. History of another malignancy (apart from myelodysplastic syndromes, basal cell carcinoma of the skin, or in situ cervix carcinoma) except if free of disease for ≥ 3 years 17. Any psychological, familial, sociological or geographical condition potentially hampering compliance with the study protocol and follow-up schedule.