Rituximab maintenance significantly prolongs progression-free survival of patients with newly diagnosed mantle cell lymphoma treated with the Nordic MCL2 protocol and autologous stem cell transplantation
Abstract
Recently, survival benefit of rituximab maintenance (RM) was confirmed in patients with mantle cell lymphoma (MCL) treated with R-DHAP and autologous stem cell transplant (ASCT). Whether RM improves outcomes in patients treated with other induction regimens is unknown.
As part of the NiHiL observational study in patients with malignant lymphomas (GovTrial No. NCT03199066) we analyzed outcome of MCL patients treated with the Nordic MCL2 protocol followed by ASCT and RM or observation.
The cohort consisted of 143 consecutive patients with median age 56 years, and with MIPI low, intermediate and high risk in 41%, 38% and 21% patients, respectively. Overall response rate (ORR) after induction in the whole cohort was 93% (67.1% CRs). 138 patients completed induction and 119 were transplanted.
ORR after ASCT was 92.4% (81.5% CRs). From 130 patients without progression within 120 days after the last therapy delivery (in 112 pts after stem cell transfer, in 18 pts after the last cycle of induction), 66 initiated RM, and 64 were observed.
With a median follow up 4.1 years median PFS was 9.8 years (5-y PFS and OS 66.2% and 74.4%, respectively) and median OS was not reached for the whole cohort. RM compared to observation significantly reduced risk of progression (5-y PFS 82.9% vs. 63.3%, p 0.004, HR 0.36, 95% CI 0.21 - 0.74), but the difference was not significant for OS.
There was no difference in PFS in RM group between patients with and without ASCT. MIPI and splenomegaly independently correlated with shorter PFS and OS.