iTeos Therapeutics announces follow-up interim data from GALAXIES Lung-201

iTeos Therapeutics announced follow-up interim data from GALAXIES Lung-201, the Phase 2 platform study sponsored by iTeos’ development partner GSK (GSK), assessing the belrestotug + dostarlimab doublet in previously untreated, unresectable, locally advanced or metastatic PD-L1 high non-small cell lung cancer. As of the June 7, 2024 data cutoff, the late-breaking interim data presented at the ESMO Congress were based on 124 patients eligible for safety and efficacy evaluation. Clinically meaningful improvement in the primary endpoint of ORR was observed consistently across each belrestotug + dostarlimab cohort. cORR, defined as complete or partial response confirmed by repeat imaging greater than or equal to 4 weeks after response criteria first met, was roughly 60.0% for each dose compared to 28.1% cORR for dostarlimab alone. Of the patients with evaluable paired ctDNA samples, median ctDNA reduction was 65% for dostarlimab monotherapy compared to 55% for Dose A, 94% for Dose B, and 97% for Dose C. Belrestotug + dostarlimab led to an increase in immune-related adverse events compared to dostarlimab monotherapy, which were generally manageable. The safety profile of belrestotug in combination with dostarlimab has been broadly consistent with the known safety profile of combination therapy with checkpoint inhibitors.