Merck said the Phase III study of the combination in non-small cell lung cancer did not meet its dual primary endpoint of overall survival and progression-free survival.

Gilead ups its investment in its TIGIT partner, as the firms pivot to a less crowded market opportunity in upper GI cancers.

Once heralded with optimism, the class of anti-TIGIT molecules has since fallen out of favor, plagued by a succession of disappointing findings.

With a $320m equity investment, Gilead will now own 33% of partner Arcus, which it said reinforces its optimism around the anti-TIGIT class for oncology.