iTeos Therapeutics, Inc. and its development partner GSK, have initiated the first, global Phase 3 registration study of belrestotug + dostarlimab doublet versus placebo + pembrolizumab in patients with previously untreated, unresectable, locally advanced or metastatic PD-L1 selected non-small cell lung cancer (NSCLC). In May 2024, iTeos announced an interim assessment of the Phase 2 GALAXIES Lung-201 study of the belrestotug + Dostarlimab doublet in previously untreated, locally advanced, or metastatic PD-L 1 selected NSCLC exceeded pre-defined efficacy criteria for clinically relevant activity and showed an acceptable safety profile in line with the TIGIT:PD-1 class. Clinically meaningful tumor reduction was observed at every belrestotug + dosterarlimab dose vs dostarlimab monotherapy.

Belrestotug is an Fc active human immunoglobulin G1, or IgG1, monoclonal antibody (mAb) targeting T cell immunoglobulin and immunoreceptor tyrosine-based inhibitory motif domains (TIGIT), an important inhibitory receptor which contributes to the suppression of innate immune responses against cancer. As an optimized high-affinity, potent anti-TIGIT mAb, belrestotug is designed to enhance the antitumor response through a multifaceted immune modulatory mechanism by engaging with TIGIT and Fc?R, a key regulator of immune responses which induces cytokine release and antibody dependent cellular cytotoxicity (ADCC). The therapeutic candidate is progressing in multiple indications in collaboration with GSK.