Rituximab maintenance improves progression-free and overall survival rates after combined immuno-chemotherapy (R-FCM) in patients with relapsed follicular and mantle cell lymphoma: Final results of a prospective randomized trial of the German Low Grade Lymphoma Study Group (GLSG)

7502 Background: Rituximab (R) prolongs the progression-free survival (PFS) in patients with follicular lymphoma (FL) when given either simultaneously with or as maintenance after chemotherapy only. Methods: In the current study the impact of R maintenance after remission induction with an R-containing combined immuno-chemotherapy (R-FCM) was evaluated. Patients with advanced stage relapsed or refractory FL and mantle cell lymphoma (MCL) were eligible. The study design comprized 4 courses of chemotherapy with Fludarabine (25 mg/m2/d days 1–3), Cyclophosphamide (200 mg/m2/d days 1–3) and Mitoxantrone (8 mg/m2/d day 1) (FCM) ± Rituximab (375 mg/m2/d day 0). Patients entering a complete (CR) or partial remission (PR) underwent a second randomization for R maintenance (4 weekly doses (375 mg/m2/d) at three and nine months after end of induction) or observation only. Randomization was stratified for histology, prior therapies (up to 2 lines vs. >2), induction (±R), and response (CR vs. PR). After improved outcome of the R-FCM arm had been observed in the initial 147 randomized patients, all subsequent patients received a combined immuno-chemotherapy induction. Results: 176 of 195 randomized cases are evaluable, 138 of whom had received an R-containing induction. In these patients (as well as the total group) the median PFS after end of induction has not been reached in the R-maintenance arm in contrast to 17 months in patients with no further treatment (p = 0.001). This improvement was seen both in FL (n = 81; p = 0,035) and MCL (n = 47; p = 0,049). More importantly, overall survival rate was also improved after R maintenance with borderline significance (3 y rate 82% vs. 55%; p = 0,056). No major sided effects of R maintenance have been observed and the rate of serious infections was similar in both study arms (p = 0.72). Conclusions: The final analysis of this study confirms that R maintenance after combined immuno-chemotherapy (R-FCM) is highly effective and improves the progression-free survival—with a strong trend towards improved overall survival—of patients with relapsed FL and MCL. [Table: see text]