Comparison of the efficacy and toxicity of treosulfan and busulfanconditioning regimens in patients undergoing stem cell transplantation due to acute myeloid leukemia

Introduction: Acute myeloid leukemia (AML) represents a heterogeneous group of aggressive blood cell cancers resulting from the clonal proliferation of malignant hematopoietic progenitor cells in the bone marrow. Leukemic cells interfere with the production of normal blood cells, leading to symptoms such as weakness, infection, and bleeding, along with various complications. AML is the most common type of acute leukemia among adults, accounting for approximately 80% of cases in this population. The incidence of the disease increases with age, with an average age of diagnosis between 68 and 70 years. It also accounts for about 1-2% of cancer-related deaths. Stem cell transplantation is considered curative in its treatment. Allogeneic hematopoietic stem cell transplantatio n (HSCT) has emerged as a potential curative treatment for various hematological malignancies and non-malignant diseases in adults. The selection of conditioning regimens is crucial for hematological diseases, as cytoreduction and chemotherapy protocols must not exceed acceptable toxicity levels. This selection is made based on various factors, including the patient's age, disease risk, and remission status at the time of transplantation. There is uncertainty regarding the optimal conditioning regimen in patients with hematological malignancies undergoing allogeneic HSCT, highlighting the need for comparative studies of these regimens. The aim of this study is to compare the toxicity profiles and clinical outcomes of two different myeloablative conditioning regimens: treosulfan-fludarabine and busulfan-cyclophosphamide. Materials and Methods: Data and statistics of patients who underwent allogeneic HSCT at Inönü University Turgut Özal Medical Center between January 2010 and December 2024 were analyzed retrospectively. Patients receiving treosulfan or busulfan as a conditioning regimen were matched one-to-one based on their diseases and ages, resulting in a total of 62 patients. The following parameters were examined in the screened patients: age, sex, diagnosis at the time of diagnosis, risk classification, donor type, pre-transplant treatment response, amount of CD+34 given, chemotherapy regimen administered, transplant date, duration of neutrophil engraftment, duration of platelet engraftment, occurrence of febrile neutropenia, length of hospital stay, mortality within 100 days, occurrence of acute GVHD, occurrence of chronic GVHD, chimerism on day 28 and day 100, occurrence of acute kidney failure, relapse status, mortality status, date of death, progression-free survival, occurrence of sinusoidal obstruction syndrome, and overall survival parameters. Results: This study was conducted with a total of 62 patients. Among the participants, 58.1% were male, 74.2% had AML, 67.7% responded to CR1 therapy prior to transplantation, and 69.4% developed febrile neutropenia. It was determined that 22.6% experienced relapse, 45.2% were still alive, and 11.3% developed acute kidney injury (AKI). Among these patients, a treosulfan-based regimen was used in 27 cases, while a busulfan-based regimen was used in 35 cases. There was no statistically significant difference between the two regimens. Conclusion: The efficacy and toxicity profiles of Treosulfan/Fludarabine/ATG and Busulfan-based (BU/CY and BU/FLUDARA/ATG) regimens in the treatment of AML have been analyzed in detail. The findings indicate that both regimens can be successfully applied to different patient groups; however, each regimen has its unique advantages and potential risks. Keywords: Akut Myeloid Lösemi, Hematopoetik Kök Hücre Nakli, Busulfan, Treosulfan