Rituximab in vivo purging is safe and effective in combination with CD34-positive selected autologous stem cell transplantation for salvage therapy in B-NHL

The purpose of this study was to evaluate feasibility and efficacy of Rituximab included into a sequential salvage protocol for CD20(+) B-NHL in relapse or induction failure. Twenty-seven patients with CD20(+) B-NHL in relapse or induction failure received Rituximab combined with DexaBEAM (IR-DexaBEAM) for stem cell mobilization. Additional ex vivo selection of CD34-positive cells was performed using the CliniMacs device. Two doses of Rituximab were included in the high-dose therapy regimen (HDT). R-DexaBEAM was well tolerated and 26 of 27 patients mobilized sufficient numbers of CD34(+) blood stem cells. Application of R-DexaBEAM resulted in significant depletion of peripheral B cells. No treatment-related deaths occurred after HDT and all patients showed stable engraftment of hematopoesis. Combined immunodeficiency was observed post HDT and eight patients developed CMV antigenemia. Remission rate post HDT was 96% (CR, 24/26; PR, 1/26). Overall and progression-free survival (PFS) at 16 months post HDT (range 6-27) is 95% and 77%, respectively. With regard to histology, PFS was 71% in aggressive lymphoma (n = 11), 74% in indolent FCL (n = 10) and 100% in MCL (n = 5). The treatment protocol has proven feasible, with high purging efficiency and encouraging remission rates.