Total marrow irradiation-based, reduced-intensity conditioning regimen for elderly patients undergoing hematopoietic cell transplantation for hematological malignancies

Abstract Background Elderly patients are increasingly being offered allogeneic hematopoietic cell transplantation (HCT), and several strategies have been developed to meet their needs. The objective of the current study was to report the feasibility of a reduced-intensity busulfan/fludarabine conditioning regimen with total marrow irradiation in older patients. Methods This single-center study included 28 patients aged 60–77 years with a median follow-up of 34 months. Results Overall survival at 2 years was 46%, relapse rate was 30%, and non-relapse mortality was 23%, yielding a progression-free survival of 46%. Rates of grades II-IV acute GVHD, III-IV acute GVHD, and chronic GVHD were 47%, 8%, and 19%, respectively. Only one patient did not achieve neutrophil engraftment. Three patients experienced sinusoidal obstruction syndrome, and all recovered. Causes of death included disease progression ( n = 10), infection ( n = 5, including one COVID-19 case), and acute myocardial infarction ( n = 1). Conclusion Our results demonstrate the feasibility of an intensified, total marrow irradiation-based conditioning regimen in an elderly cohort, primarily comprising transplants from alternative donors for high-risk diseases. Non-relapse mortality was very low, given the patients’ profile, and compares favorably with others reports reduced-intensity regimen with total body irradiation in older patients. Future studies should compare it to the standard reduced-intensity and non-myeloablative regimens.