Gilead Sciences is walking away from most of its TIGIT collaboration with Arcus Biosciences after STAR-121, a Phase 3 study of domvanalimab in metastatic non-small cell lung cancer, was stopped for futility.
An independent data monitoring committee found the combination of domvanalimab plus a PD-1 blocker and chemotherapy couldn’t beat Merck’s Keytruda plus chemotherapy. Arcus disclosed the result in a securities filing dated April 20, without providing specific trial data. No new safety issues emerged from the data review, though the futility analysis didn’t include a safety assessment.
Gilead didn’t wait. The company has declined to make an option continuation payment, ending its access to early-stage TIGIT programs from Arcus. The partners are also shutting down the Phase 2 EDGE-Lung study of domvanalimab in NSCLC.
Three programs survive in Gilead’s hands: the AXL blocker AB801, anti-CD39 antibody AB598, and MRGPRX2 antagonist AB102. The filing doesn’t say when those options expire.
The May 2020 Gilead-Arcus partnership once looked like it might buck the TIGIT trend. A June 2024 Phase 2 readout showed domvanalimab delivering a 58.5% overall response rate in upper GI cancers, while Roche, Merck, and GSK’s TIGIT programs were already collapsing around them. Then came December’s flop in gastric and esophageal cancer. Now this.
TIGIT’s total toll: at least $1.4 billion paid upfront across partnership deals, with up to $5 billion in milestones largely unpaid. Gilead’s formal exit from new Arcus early-stage programs closes on July 14.
Sarah Chen