iTeos Announces Clinically Meaningful Objective Response Rate Observed at Every Dose in Follow-up Interim Analysis of GALAXIES Lung-201 Study of Belrestotug + Dostarlimab in First-Line, PD-L1 High Non-Small Cell Lung Cancer Patients

Core Insights - iTeos Therapeutics announced promising interim data from the GALAXIES Lung-201 study, showing a clinically meaningful objective response rate (ORR) of 63.3-76.7% for the belrestotug + dostarlimab combination in patients with PD-L1 high non-small cell lung cancer (NSCLC) [1][2][4] - The confirmed ORR (cORR) was approximately 60% across all doses, with a significant 30% improvement compared to dostarlimab monotherapy [1][2][4] - The safety profile of the combination therapy was consistent with known safety profiles of checkpoint inhibitor combinations, with manageable immune-related adverse events [1][4] Study Details - The GALAXIES Lung-201 study is a Phase 2 trial evaluating the efficacy and safety of belrestotug + dostarlimab in previously untreated, unresectable, locally advanced or metastatic PD-L1 high NSCLC [7][8] - The study included 124 patients, with a median follow-up of 5.6 months, assessing various dose levels of dostarlimab and belrestotug [3][5] - The primary endpoint is investigator-assessed ORR, with secondary endpoints including safety, progression-free survival, overall survival, and duration of response [8] Efficacy Results - The ORR for the belrestotug + dostarlimab combination was 63.3% for Dose A, 65.6% for Dose B, and 76.7% for Dose C, compared to 37.5% for dostarlimab alone [4][5] - The cORR was 60.0% for each dose of the combination therapy, significantly higher than the 28.1% cORR for dostarlimab monotherapy [4][5] - Median ctDNA reduction was 65% for dostarlimab alone, while reductions were 55%, 94%, and 97% for Doses A, B, and C, respectively [4] Safety Profile - The combination therapy led to an increase in immune-related adverse events compared to dostarlimab alone, with the most common treatment-related adverse events being skin and subcutaneous tissue disorders (50%) and endocrine disorders (26%) [4][10] - The safety profile of belrestotug in combination with dostarlimab aligns with the known safety profile of combination therapies involving checkpoint inhibitors [4] Future Outlook - iTeos plans to initiate the GALAXIES Lung-301 Phase 3 trial based on the encouraging results from the interim analysis of the GALAXIES Lung-201 study [2][4] - A conference call to discuss the interim data will be held on September 16, 2024 [6]