Radioimmunotherapy-augmented BEAM chemotherapy vs BEAM alone as the high-dose regimen for autologous stem cell transplantation

Relapse remains the most common cause of treatment failure in patients receiving autologous stem cell transplantation (ASCT) for follicular lymphoma (FL). The aim of this study was to evaluate the effect of adding radioimmunotherapy or rituximab (R) to BEAM (carmustine, etoposide, ara-c, melphalan) high-dose therapy for ASCT in patients with relapsed FL. Using the European Society for Blood and Marrow Transplantation registry, we conducted a cohort comparison of BEAM (n=1973), Zevalin-BEAM (Z-BEAM) (n=207) and R-BEAM (n=179) and also a matched-cohort analysis of BEAM vs Z-BEAM including 282 and 154 patients, respectively. BEAM, Z-BEAM and R-BEAM groups were well balanced for age, time from diagnosis to ASCT and disease status at ASCT. The cumulative incidences of relapse (IR) at 2 years were 34, 34 and 32% for Z-BEAM, R-BEAM and BEAM, respectively. By multivariate analysis, there were no significant differences with Z-BEAM or R-BEAM compared with BEAM for IR, non-relapse mortality, event-free survival or overall survival. With the caveat that the limitations of registry analyses have to be taken into account, this study does not support adding radioimmunotherapy or R to BEAM in ASCT for relapsed FL. However, we cannot rule out the existence a particular subset of patients who could benefit from Z-BEAM conditioning that cannot be identified in our series, and this should be tested in a randomized trial. Bone Marrow Transplantation (2017) 52, 1120-1125; doi: 10.1038/bmt.2017.88; published online 22 May 2017