Busulfan (BU) Plus Fludarabine Vs Intravenous BU Plus Cyclophosphamide as Conditioning Regimens Prior Allogeneic Hematopoetic Stem Cells Transplant (HSCT) in AML

The purpose of this prospective phase III, open-label, randomized multicenter study is to evaluate whether Acute Myeloid Leukemia (AML) elderly patients in Complete Remission (CR) undergoing allogeneic hematopoietic stem cell transplantation after a reduce toxicity conditioning regimen (I.V. BuFlu) as compared to the conventional I.V. BuCy2 program will experience: 1. A lower transplant-related mortality (TRM) at 1 year after Hematopoietic Stem Cells Transplant (HSCT) 2. A similar anti-leukemic activity and a similar or better safety profile, in terms of: * Early and/or late graft rejection * Hematopoietic and immunologic recovery * Chimerism * Toxicity and incidence of Veno-occlusive Disease (VOD) * Acute (aGvHD) and chronic graft-versus-host disease (cGvHD) * Cumulative incidence of TRM at +100 days and 2 years after transplant * Cumulative incidence of relapse by 1 and 2 years after transplant * Event-free (EFS) and overall survival (OS) by 1 and 2 years after transplant