Efficacy and Toxicity of Conditioning Regimens BEAM and BEM in Autologous Hematopoietic Cell Transplantation for Lymphomas: Preliminary Results of a Comparative (Matched Pair) Analysis

Abstract 4530

Autologous hematopoietic cell transplantation (AHCT) is the standard of care for relapsed or primary refractory Hodgkin's (HL) and Non Hodgkin's lymphoma (NHL). The conditioning regimens used are considered equal and none has demonstrated any superiority. During the last 2 years, primarily due to Carmustine (BCNU) unavailability, a new alternative conditioning regimen was constructed in our unit consisting of intravenous Busulphan (Busilvex) (3.2mg/kg/day for 3 days), Etoposide (400mg/m^∧2/day for 2 days) and Melphalan (140mg/m^∧2) (BEM). We retrospectively analysed the outcome of patients (pts) who underwent AHCT following conditioning with the standard BEAM and BEM regimen. The pts were stratified by age, pre-transplantation disease phase and previous lines of treatment. In total, 50 pts conditioned with BEM (group A) and 93 pts with BEAM (group B) were included. Group B pts were selected among 184 pts who underwent AHCT with BEAM regimen during the last decade. Stratification by disease risk was followed by a 1:2 selection. Fifty percent of the pts were younger than 34 in both study groups with a range of 11–68 years old. The pts of group B were more likely to suffer from HL (63) than NHL (30); whereas disease diagnosis for group A was HL in 28 and NHL in 22 pts. Disease was chemoresistant to salvage treatment in 46% of group A pts versus (vs) 23% of group B pts. There were no other significant differences concerning the patients' characteristics such as age above median, pre-transplantation lines of treatment (1–2: 40%, 3–4: 46%, ≥5: 14%), disease status (complete remission: 27%, primary refractory: 52%, relapse: 21%), advanced stage disease (52%). Complete remission post-AHCT was obtained in 50% of group A and 56% of group B pts. Progression free survival (PFS) at 2 years and overall survival (OS) were similar among the two study group populations (66% vs 63% and 80% vs 78% respectively). Given the fact that there were more pts with chemoresistant disease in group A, a second matched pair analysis was conducted upon stratification by disease chemosensitivity to salvage treatment instead of age as a risk factor. Efficacy was again similar for both conditioning regimens. In multivariate analysis favorable factors in terms of PFS were HL, chemosensitivity to salvage treatment and stage <IIB whereas in terms of OS non-bulky disease, HL and stage <IIB. Treatment related mortality (TRM) was 3.2% (3/93 pts) in group B and no TRM in group A. Detailed toxicity associated with the two study regimens is further analyzed. There are currently no randomized studies clarifying the optimal conditioning among multiple regimens in terms of efficacy and toxicity. In this study the two conditioning regimens, BEAM and BEM, were found to be equivalent. Additionally, the efficacy of the newly designed BEM regimen in chemoresistant and advanced stage disease is encouraging.