Evaluate the Efficacy of Myeloablative Conditioning Regimens for Allogeneic Hematopoietic Stem Cell Transplantation in Acute Myelogenous Leukemia at BTH, Vietnam

Background: Busulfan plus cyclophosphamide (Bu/Cy) is considered one of the classical myeloablative conditioning regimens. However, its toxicity can significantly increase mortality rates. To reduce both acute and long-term complications after hematopoietic stem cell transplantation (HSCT), newer conditioning regimens are being investigated. The purposes of this study were to assess the efficacy and safety of busulfan plus cyclophosphamide (Bu/Cy) and busulfan plus fludarabine (Bu/Flu) conditioning regimen for allogeneic HSCT (allo-HSCT) in acute myelogenous leukemia (AML). Materials and Methods: We conducted a single-center, retrospective analysis of AML, both adults and children, who underwent either Bu/Cy or Bu/Flu conditioning regimen for allo-HSCT and received peripheral blood stem cell transplants from HLA-matched donors. Results: From 2005 – 2019, 49 AML patients receiving Bu/Cy and 21 receiving Bu/Flu were identified, meeting inclusion criteria. The two groups showed no significant differences in age, gender, disease status pre-transplant, the median time to neutrophil and platelet engraftment. Bu/Flu patients had a shorter duration of neutropenia (median 7 days vs 10 days, p = 0.001) and shorter duration of thrombocytopenia (median 10 days vs 15 days, p = 0.016) than Bu/Cy.  No difference was observed in disease-free survival (DFS) and overall survival (OS) between the two groups. Both univariate and multivariate analyses showed that age, disease status pre-transplant, and chronic graft-versus-host disease (GvHD) are related to worse DFS and OS. Conclusion: With similar efficacy to Bu/Cy but faster neutrophil and platelet recovery time, Bu/Flu is suitable as a pre-HSCT conditioning regimen for patients with AML.