Efficacy of BEAM versus BeEAM conditioning regimens in autologous hematopoietic stem cell transplantation for diffuse large B-cell lymphoma: a retrospective single-center study.

The BEAM regimen (carmustine, etoposide, cytarabine, melphalan) is the standard conditioning regimen for autologous hematopoietic stem cell transplantation (auto-HSCT) in diffuse large B-cell lymphoma (DLBCL). Due to global carmustine shortages, bendamustine-based BeEAM has been proposed as an alternative. This study compared clinical outcomes between BEAM and BeEAM regimens in DLBCL patients undergoing auto-HSCT. A retrospective analysis of 60 consecutive DLBCL patients undergoing auto-HSCT (2019-2024) was conducted. Patients received either BEAM (n=45) or BeEAM (n=15) conditioning. Endpoints included progression-free survival (PFS), overall survival (OS), and treatment response. Survival outcomes were analyzed using the Kaplan-Meier method and the log-rank test. The BEAM group demonstrated significantly superior 3-year PFS (88.7% vs. 75.8%, p=0.024) and OS (95.3% vs. 68.9%, p=0.017) compared to BeEAM. In consolidation patients (n=50), BEAM showed numerically better PFS (89.5% vs. 81.8%, p=0.25) and OS (94.5% vs. 80.8%, p=0.069). Among patients with a pre-transplant complete response (n=52), BEAM showed significantly improved 3-year OS (94.2% vs. 68.9%, p=0.04) and numerically better PFS (86.1% vs. 75.8%, p=0.059). All patients engrafted successfully with comparable neutrophil and platelet recovery. The complete response rate improved from 86.7% (52/60) pre-transplant to 100% (60/60) post-transplant. In summary, BEAM may be associated with better outcomes than BeEAM in this cohort. However, due to the limited sample size, these findings should be interpreted as exploratory, and larger prospective studies are needed to validate these observations.