The treatment of relapsed/refractory acute myeloid leukemia (AML) is associated with a dismal prognosis. The allogeneic hematopoietic cell transplantation (allo-HCT) is frequently performed as salvage therapy. Reduced intensity conditioning protocols have been developed with the aim of reducing the leukemia burden without increasing their toxicity. We compared the reduced intensity conditioning FM140 (fludarabine, 150 mg/m2; melphalan 140 mg/m2) with FBM110 (fludarabine 150 mg/m2; BCNU, also known as carmustine, 300-400 mg/m2; and melphalan 110 mg/m2). From the European Bone Marrow Transplantation (EBMT) Acute Leukemia Working Party registry, we identified 293 adult patients (FM140, n = 118 and FBM110, n = 175) with AML with relapsed/refractory disease prior to allo-HCT. There were some differences such as age (FM140 = 59.5 years vs. FBM110 = 65.1 years, p < 0.001) and graft-versus-host disease (GvHD) prophylaxis based on in vivo T-cell depletion (TCD, FM140 = 39% vs. FBM110 = 75%, p < 0.001). No differences were observed between FM140- and FBM110-treated patients regarding overall survival (OS) (2-year OS: 39.3% vs. 45.7%, p = 0.58), progression-free survival (PFS) (2-year PFS: 36.1% vs. 37.3%, p = 0.69), non-relapse mortality (NRM) (2-year NRM: 15.3% vs. 25.7%, p = 0.10) and relapse incidence (RI) (2-year RI: 48.6% vs. 37.0%, p = 0.7). In conclusion, despite differences in age and GvHD prophylaxis, AML patients with active disease undergoing allo-HCT after FBM110 conditioning showed similar outcomes compared to FM140.

Department for Hematology Oncology and Immunology University Hospital Giessen and Marburg Campus Marburg Philipps Universität Marburg Marburg Germany

Department of Haematology Hemostasis Oncology and Stem Cell Transplantation Hannover Medical School Hannover Germany

Department of Haematology Sorbonne University Saint Antoine Hospital AP HP INSERM UMRs 938 Paris France

Department of Hematology A Z Sint Jan Brugge Belgium

Department of Hematology and Medical Oncology University Hospital Goettingen Goettingen Germany

Department of Hematology and Oncology University Medical Center Mainz Mainz Germany

Department of Hematology and Oncology University of Regensburg Regensburg Germany

Department of Hematology Oncology Charles University Hospital Pilsen Czech Republic

Department of Hematology Oncology Faculty of Medicine University of Freiburg Medical Center Freiburg Germany

Department of Hematology Oncology University of Muenster Muenster Germany

Department of Internal Medicine 3 University Hospital Ulm Ulm Germany

Department of Internal Medicine 5 University Hospital Erlangen Erlangen Germany

Department of Medicine 2 Goethe University Frankfurt am Main Germany

Division of Internal Medicine 1 University Hospital of Patras Patras Greece

EBMT Statistical Unit INSERM UMRs 938 Hôpital Saint Antoine Paris France

Hematology Division Chaim Sheba Medical Center Tel Hashomer Israel

IRCCS San Raffaele Scientific Institute University Vita Salute Milan Italy

Medical Department 1 University Hospital Carl Gustav Carus TU Dresden Dresden Germany

Medical Department 2 University Hospital Wuerzburg Wuerzburg Germany

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