Rituximab Improves the Outcome of Upfront Autologous Stem Cell Transplantation in Mantle Cell Lymphoma: A Comparison of Different Strategies.

Introduction: First-line autologous stem cell transplantation (SCT) is an accepted therapy for mantle cell lymphoma (MCL). We have recently shown that 2 standard doses of rituximab significantly improve the outcome of TBI-based upfront SCT in MCL when administered peritransplant (Haematologica 92:42; 2007). The purpose of the present retrospective analysis was to compare this approach with alternative rituximab-based strategies. Patients and treatment strategies: 34 consecutive patients treated in KI-HH received 3–6 cycles of CHOP prior to stem cell mobilization with Dexa-BEAM (n=20) or DHAP (n=14), followed by TBI-cyclophosphamide-rituximab myeloablation and SCT (CHOP/R-TBI-CY group). Patients treated in HD received 3–8 cycles of R-CHOP for cytoreduction (n=28) and mobilization (n=23; the remaining 5 patients were mobilized with R-DHAP/HAM) followed by BEAM and SCT (R-CHOP/BEAM group). 12 patients of this group received additional rituximab maintenance after SCT.

Results: With a median follow-up of 38 months (9–111), estimated 4-year progression-free survival (PFS) from diagnosis of patients treated with CHOP/R-TBI-CY and R-CHOP/BEAM was 83% and 72% (log rank, p=.38), respectively. Of note, with a median follow-up of 30 months (14–57) there was no relapse in the 12 pts receiving maintenance therapy with rituximab, translating into a significantly better 4-y PFS in patients receiving R-CHOP/BEAM with rituximab maintenance vs those without (100% vs. 56%; p=.021). The PFS difference between the R-CHOP/BEAM group and the CHOP/R-TBI-CY group became borderline significant after omitting the rituximab maintenance patients (p=.055).

Conclusions: In advanced-stage MCL, addition of rituximab improves disease control provided by first-line SCT. Whereas the exact dose and timing of rituximab administration remains to be settled, prospective investigation of post-transplant rituximab maintenance appears to be particularly promising.