Rituximab Maintenance Improves Clinical Outcome of Relapsed/resistant Follicular Non-Hodgkin Lymphoma in Patients Both with and Without Rituximab During Induction: Results of a Prospective Randomized Phase 3 Intergroup Trial

We evaluated the role of rituximab (R) both in remission induction and maintenance treatment of relapsed/resistant follicular lymphoma (FL). A total of 465 patients were randomized to induction with 6 cycles of cyclophosphamide, doxorubicin, vincristine, and prednisone (CHOP) (every 3 weeks) or R-CHOP (R: 375 mg/m(2) intravenously, day 1). Those in complete remission (CR) or partial remission (PR) were randomized to maintenance with R (375 mg/m(2) intravenously once every 3 months for a maximum of 2 years) or observation. R-CHOP induction yielded an increased overall response rate (CHOP, 72.3%; R-CHOP, 85.1%; P < .001) and CR rate (CHOP, 15.6%; R-CHOP, 29.5%; P < .001). Median progression-free survival (PFS) from first randomization was 20.2 months after CHOP versus 33.1 months after R-CHOP (hazard ratio [HR], 0.65; P < .001). Rituximab maintenance yielded a median PFS from second randomization of 51.5 months versus 14.9 months with observation (HR, 0.40; P < .001). Improved PFS was found both after induction with CHOP (HR, 0.30; P < .001) and R-CHOP (HR, 0.54; P = .004). R maintenance also improved overall survival from second randomization: 85% at 3 years versus 77% with observation (HR, 0.52; P = .011). This is the first trial showing that in relapsed/resistant FL rituximab maintenance considerably improves PFS not only after CHOP but also after R-CHOP induction.