07:54 AM EDT, 07/08/2024 (MT Newswires) -- iTeos Therapeutics ( ITOS ) said Monday it has dosed the first patient in its phase 3 trial of belrestotug with dostarlimab, triggering a $35 million development milestone payment from its belrestotug partner GSK (GSK).

The global, randomized, double-blind trial aims to compare the efficacy of belrestotug with dostarlimab against a placebo combined with pembrolizumab in patients with first-line advanced, unresectable, or metastatic PD-L1 high non-small cell lung cancer.

In June 2021, iTeos and GSK entered into an exclusive development and commercialization collaboration for belrestotug. Under the agreement, iTeos received a $625 million upfront payment from GSK with potential development and regulatory milestones up to $550 million and commercial milestones up to $900 million, iTeos said.