Anti-LAG-3 with or without anti-PD-1 in recurrent glioblastoma: a phase 1 trial

Lymphocyte activation gene 3 (LAG-3) is an immune checkpoint implicated in T cell exhaustion and a potential therapeutic target in glioblastoma (GBM). We conducted a multicenter, open-label, phase 1 study with sequential allocation to evaluate the safety and preliminary activity of the anti-LAG-3 antibody relatlimab, administered alone or with the anti-programmed cell death protein 1 (PD-1) antibody nivolumab, in patients with recurrent GBM. Forty-six patients were treated (23 per cohort). The primary endpoint of safety was met, with maximum tolerated doses of 800 mg relatlimab for monotherapy and 160 mg relatlimab/240 mg nivolumab for combination therapy. Treatment-related grade 3-4 adverse events occurred in 6 of 23 patients receiving combination therapy and were not observed with monotherapy. Neoadjuvant administration was associated with increased intratumoral CD8⁺ T cell infiltration for both monotherapy and combination therapy. Exploratory analyses suggested that tumors with elevated baseline interferon signaling and increased T cell clonality were enriched among patients with durable responses to combination therapy. Twelve-month overall survival was 34.8% with relatlimab alone and 52.2% with combination therapy; however, this study was not designed to assess efficacy. These findings demonstrate an acceptable safety profile and provide preliminary immunologic and clinical signals supporting further evaluation of LAG-3 blockade in GBM. ClinicalTrials.gov identifier: NCT02658981 .