Clofarabine/busulfan-based reduced intensity conditioning regimens provides very good survivals in acute myeloid leukemia patients in complete remission at transplant: a retrospective study on behalf of the SFGM-TC

// Amandine Le Bourgeois 1 , Myriam Labopin 2 , Mathieu Leclerc 3 , Regis Peffault de Latour 4 , Jean-Henri Bourhis 5 , Patrice Ceballos 6 , Corentin Orvain 7 , Helene Labussiere Wallet 8 , Karin Bilger 9 , Didier Blaise 10 , Marie-Therese Rubio 11 , Thierry Guillaume 1 , Mohamad Mohty 2 , Patrice Chevallier 1 and on behalf of Societe Francophone de Greffe de Moelle et de Therapie Cellulaire 1 Department of Hematology, CHU Hotel Dieu, Nantes, France 2 Department of Hematology, Hopital Saint Antoine, Paris, France 3 Department of Hematology, Hopital Henri Mondor, Creteil, France 4 Department of Hematology, Hopital Saint Louis, Universite Paris 7, Denis Diderot, Paris, France 5 Department of Hematology, Hopital Gustave Roussy, Paris, France 6 Department of Hematology, CHU de Montpellier, Montpellier, France 7 Department of Hematology, CHU d’Angers, Angers, France 8 Department of Hematology, Centre Hospitalier Lyon Sud, Lyon, France 9 Department of Hematology, CHU Strasbourg, Strasbourg, France 10 Department of Hematology, Centre de Recherche en Cancerologie de Marseille, Institut Paoli Calmettes, Marseille, France 11 Department of Hematology, CHU Nancy, Nancy, France Correspondence to: Amandine Le Bourgeois, email: amandine.lebourgeois@chu-nantes.fr Patrice Chevallier, email: patrice.chevallier@chu-nantes.fr Keywords: allogeneic stem cell transplantation; clofarabine; busulfan; reduced intensity conditioning regimen; acute myeloid leukemia Received: August 24, 2018 Accepted: November 01, 2018 Published: November 27, 2018 ABSTRACT Background: Clofarabine has been proved to have higher anti-leukemic myeloid activity compared to fludarabine, a drug extensively used as part of reduced intensity conditioning (RIC) for allogeneic stem cell transplantation (allo-SCT). Results: Eighty-four patients were included. The majority of patients had acute myeloid leukemia (AML, n = 63). Sixty-one patients were in complete remission (AML n = 55). With a median follow up of 31 months (range: 5.7–74.1), 2-year overall (OS) and disease-free (DFS) survivals, relapse incidence (RI), non-relapse mortality (NRM) and graft-versus-host disease (GVHD)/relapse free survival (GRFS) were 64.5% (53.8–75.2); 57.2% (46.2–68.2); 27.7% (18.2–37.9); 15.1% (8.2–23.9) and 43.6% (32.5–54.7), respectively. Considering AML in remission, 2-year OS, DFS, RI, NRM and GRFS were 74.2% (62–86.5); 66.8% (53.6–79.9); 23.4% (12.7–36); 9.8% (3.5–19.9) and 50.9% (36.9–64.9), respectively. Two-year outcomes were similar between CloB2A1 and CloB2A2 sub-groups. In multivariate analysis, active disease at transplant was the only factor adversely impacting 2 years outcomes. Conclusions: CloB2A2/A1 RIC regimen provides very good results for AML patients allografted in CR and could be retained as a new RIC platform for these patients. Materials and Methods: This was a retrospective study including all patients who received a clofarabine/busulfan based RIC allo-SCT for myeloid malignancies and reported within the SFGM-TC registry. RIC regimen consisted of clofarabine 30 mg/m²/day 4 to 5 days (Clo), busulfan 3.2 mg/kg/day 2 days (B2) and 2.5 mg/kg/day of rabbit anti-thymocyte globulin 1 or 2 days (A1 or A2). The primary objective of the study was to report the main outcomes of the whole cohort at 2 years.