Overall Survival Benefit in Patients With Rituximab-Refractory Indolent Non-Hodgkin Lymphoma Who Received Obinutuzumab Plus Bendamustine Induction and Obinutuzumab Maintenance in the GADOLIN Study

Abstract

Purpose To perform an updated analysis of the randomized phase III GADOLIN trial in patients with rituximab-refractory indolent non-Hodgkin lymphoma treated with obinutuzumab (GA101; G) and bendamustine (B). Patients and Methods Patients with histologically documented, rituximab-refractory CD20⁺ indolent non-Hodgkin lymphoma received G 1,000 mg (days 1, 8, and 15, cycle 1; day 1, cycles 2 to 6) plus B 90 mg/m²/d (days 1 and 2, all cycles) or B 120 mg/m²/d monotherapy. Patients who did not experience disease progression with G-B received G maintenance (1,000 mg every 2 months) for up to 2 years. The primary end point was progression-free survival (PFS). Results Of 413 randomly assigned patients (intention-to-treat [ITT]: G-B, n = 204; B monotherapy, n = 209), 335 had follicular lymphoma (FL; G-B, n = 164; B monotherapy, n = 171). After a median follow-up of 31.8 months, median PFS in ITT patients was 25.8 months (G-B) and 14.1 months (B monotherapy; hazard ratio [HR], 0.57; 95% CI, 0.44 to 0.73; P < .001). Overall survival (OS) also was prolonged (HR, 0.67; 95% CI, 0.47 to 0.96; P = .027). PFS and OS benefits were similar in patients with FL. Grade 3 to 5 adverse events (AEs) were reported by 148 (72.5%) and 133 (65.5%) patients in the G-B and B monotherapy arms, respectively, most commonly neutropenia (G-B, 34.8%; B monotherapy, 27.1%), thrombocytopenia (10.8% and 15.8%), anemia (7.4% and 10.8%), and infusion-related reactions (9.3% and 3.4%). Serious AEs occurred in 89 G-B patients (43.6%) and 75 B monotherapy patients (36.9%); fatal AEs occurred in 16 (7.8%) and 13 (6.4%), respectively. Conclusion This updated analysis confirms the PFS benefit for G-B shown in the primary analysis. A substantial OS benefit also was demonstrated in the ITT population and in patients with FL. Toxicity was similar for both treatments.

Trial registration: ClinicalTrials.gov NCT01059630.