iTeos Therapeutics has announced the latest data from the Phase 2 platform study GALAXIES Lung-201, led by its development partner GSK. The study evaluates the efficacy of the combination therapy consisting of the anti-TIGIT monoclonal antibody belrestotug and the anti-PD-1 monoclonal antibody dostarlimab in patients with untreated, unresectable, locally advanced, or metastatic PD-L1 high-expressing non-small cell lung cancer (NSCLC).
Belrestotug is a human immunoglobulin G1 (IgG1) anti-TIGIT monoclonal antibody with Fc activity. In 2021, GSK entered into a development collaboration with iTeos Therapeutics that could be worth up to $2 billion for the co-development of this therapy.
As of the data cutoff date of June 7, 2024, the data presented at the European Society for Medical Oncology (ESMO) annual meeting were based on 124 patients who met the safety and efficacy assessment criteria. They received the following dose levels of dostarlimab or the combination of belrestotug/dostarlimab: dostarlimab 500 mg, belrestotug 100 mg/dostarlimab 500 mg (Dose A), belrestotug 400 mg/dostarlimab 500 mg (Dose B), and belrestotug 1000 mg/dostarlimab 500 mg (Dose C).
Across all belrestotug/dostarlimab combination cohorts, the primary endpoint of ORR showed clinically meaningful improvements (63.3% for Dose A, 65.6% for Dose B, and 76.7% for Dose C) compared to a dostarlimab monotherapy ORR of 37.5%. Confirmed ORR is defined as complete or partial response confirmed by repeat imaging more than 4 weeks after first reaching response criteria. The confirmed ORR for the three dose groups was approximately 60.0%, compared to a confirmed ORR of 28.1% for dostarlimab.
The combination of belrestotug/dostarlimab led to an increase in immune-related adverse events compared to dostarlimab alone, but overall were manageable. The safety profile of the combination is largely consistent with the known safety profile of checkpoint inhibitor combination therapies. The most common treatment-related adverse events (≥15%) were skin and subcutaneous tissue disorders (50%) and endocrine disorders (26%). There were 3 patient deaths in the belrestotug/dostarlimab group attributed to treatment-related adverse events. – Flcube.com
