The phase III GALLIUM trial assessed the safety and efficacy of obinutuzumab-based versus rituximab-based immunochemotherapy in patients with previously untreated follicular lymphoma (FL) or marginal zone lymphoma (MZL). At the primary analysis, the trial met its primary end point, demonstrating improvement in investigator-assessed progression-free survival (PFS) with obinutuzumab-based versus rituximab-based immunochemotherapy in patients with FL. We report the results of the final analysis in the FL population, with an additional exploratory analysis in the MZL subgroup. Overall, 1202 patients with FL were randomized 1:1 to obinutuzumab- or rituximab-based immunochemotherapy followed by maintenance with the same antibody for up to 2 years. After a median 7.9 (range, 0.0-9.8) years of follow-up, PFS remained improved with obinutuzumab- versus rituximab-based immunochemotherapy, with 7-year PFS rates of 63.4% versus 55.7% ( P = 0.006). Time-to-next antilymphoma treatment was also improved (74.1% versus 65.4% of patients had not started their next antilymphoma treatment at 7 y; P = 0.001). Overall survival was similar between the arms (88.5% versus 87.2%; P = 0.36). Irrespective of the treatment received, PFS and OS were higher in patients with a complete molecular response (CMR) versus those with no CMR ( P < 0.001). Serious adverse events were reported in 48.9% and 43.4% of patients in the obinutuzumab and rituximab arms, respectively; there was no difference in the rate of fatal adverse events (4.4% and 4.5%, respectively). No new safety signals were reported. These data demonstrate the long-term benefit of obinutuzumab-based immunochemotherapy and confirm its role as a standard-of-care for the first-line treatment of advanced-stage FL, taking into account patient characteristics and safety considerations., Competing Interests: WT reports honoraria from F. Hoffmann-La Roche Ltd, Gilead Sciences, and Bristol-Myers Squibb, consultancy fees from F. Hoffmann-La Roche Ltd, Bristol-Myers Squibb, Incyte, and Takeda, and travel and conference registration fees from F. Hoffmann-La Roche Ltd, Gilead Sciences, and Takeda. WH reports honoraria from F. Hoffmann-La Roche Ltd, Janssen, Gilead Sciences and Celgene; a consulting/advisory role for F. Hoffmann-La Roche Ltd, Janssen and Gilead Sciences; speakers’ bureau for F. Hoffmann-La Roche Ltd, Janssen and Gilead Sciences; research funding from F. Hoffmann-La Roche Ltd, Janssen and Bayer; and travel expenses/accommodation from F. Hoffmann-La Roche Ltd, Janssen and Gilead Sciences. CB reports honoraria and speakers’ bureau fees from, and a consulting/advisory role for F. Hoffmann-La Roche Ltd, Pfizer, Janssen, Hexal, Celltrion Healthcare, AbbVie, Novartis, Bayer, MorphoSys, Regeneron Pharmaceuticals, and BeiGene; and research funding from F. Hoffmann-La Roche Ltd, Janssen, Celltrion Healthcare, AbbVie, Bayer, Amgen, and MSD. GC reports a consultancy role for F. Hoffmann-La Roche Ltd and Celgene; and honoraria from Bristol-Myers Squibb, Sanofi, Janssen, Gilead Sciences, AbbVie, Takeda, F. Hoffmann-La Roche Ltd, and Celgene. DC acknowledges support and funding from the Royal Marsden NIHR Biomedical Research Center. MJSD reports research funding from F. Hoffmann-La Roche Ltd. JGG reports grants and personal fees from Celgene, AstraZeneca and Janssen; and personal fees from AbbVie, Gilead, Karyopharm, MorphoSys, Novartis, and T.G. Therapeutics.EP reports speakers’ fees from Gilead Sciences, advisory board fees from BeiGene, virtual conference attendance fees from Celgene, and travel and conference registration fees from Takeda. MD reports research funding from AbbVie, Bayer, Bristol-Myers Squibb/Celgene, Gilead Sciences/Kite, Janssen, and F. Hoffmann-La Roche Ltd; honoraria from Amgen, AstraZeneca, Gilead Sciences/Kite, Janssen, Lilly, Novartis, and F. Hoffmann-La Roche Ltd; and membership on an entity’s Board of Directors or advisory committees for AstraZeneca, BeiGene, Bristol-Myers Squibb/Celgene, Gilead Sciences/Kite, Janssen, Lilly/Loxo Oncology, Novartis, and F. Hoffmann-La Roche Ltd. JFS reports speakers’ bureau fees, advisory board fees, and research funding from AbbVie, advisory board fees from AstraZeneca, advisory board fees from BeiGene, advisory board fees and research funding from Bristol-Myers Squibb, scientific advisory board membership from Genor Biopharma, advisory board fees from Gilead, advisory board fees and research funding from Janssen, advisory board fees, speakers’ bureau fees, research funding and expert testimony fees from F. Hoffmann-La Roche Ltd, and advisory and expert testimony fees from TG Therapeutics. JT reports research funding from F. Hoffmann-La Roche Ltd, Celgene, Janssen, PCYC, and BeiGene. DK, TGN, and AK is employed by and has equity ownership interests in F. Hoffmann-La Roche Ltd. MH reports a consultancy/advisory role with Celgene, Gilead, and F. Hoffmann-La Roche Ltd and research funding from F. Hoffmann-La Roche Ltd. RM reports honoraria from F. Hoffmann-La Roche Ltd and Janssen. All the other authors have no conflicts of interest to disclose., (Copyright © 2023 the Author(s). Published by Wolters Kluwer Health, Inc. on behalf of the European Hematology Association.)