Obinutuzumab plus bendamustine as first-line therapy for indolent B-cell lymphomas: a prospective multicenter open-label study.

This study evaluated the efficacy and safety of obinutuzumab plus bendamustine (GB) as first-line treatment for indolent B-cell lymphomas. In this prospective, multicenter, single-arm trial (NCT06415708), adults with newly diagnosed indolent B-cell lymphomas-including follicular lymphoma (FL), marginal zone lymphoma (MZL), Waldenström macroglobulinemia (WM), hairy cell leukemia variant (HCL-v), and unclassified B-cell lymphoproliferative disorder (BCLPD-U)-received six induction cycles of GB followed by 2 years of obinutuzumab maintenance in responders (⩾ partial response). The primary endpoint was overall response rate (ORR), whereas secondary endpoints included complete response rate (CRR), duration of response (DOR), progression-free survival (PFS), overall survival (OS), and safety. Among 220 enrolled patients (149 with FL and 71 with non-FL), 210 completed ⩾ 3 treatment cycles. At a median follow-up of 13.1 months, ORRs in the different patient subgroups were 96.6% (FL), 100% (MZL, HCL-v), 92.9% (WM), and 88.9% (BCLPD-U). The median DOR was 16.7 months in the FL group and was not reached in the non-FL group. PFS and OS were not reached in any subgroup. The FL and non-FL groups had comparable ORRs (P = 0.435); however, the FL group showed a higher CRR (92.4% vs. 78.5%; P = 0.004) and shorter PFS (P = 0.020). Treatment-emergent adverse events occurred in 42 patients and were more frequent in the non-FL group than in the FL group (26.8% vs. 15.4%; P = 0.046), particularly infections (18.3% vs. 6.0%; P = 0.005). Overall, the GB regimen demonstrated high response rates and manageable safety in Chinese patients with indolent B-cell lymphoma.