iTeos’s TIGIT enters Arcus territory

After a delay iTeos today claimed that the phase 2 Galaxies Lung-201 study of its lead asset, the GSK-partnered anti-TIGIT MAb belrestotug, met “predefined efficacy criteria”. The trial, testing a combo with Jemperli in first-line NSCLC, is likely a gating factor for the start of phase 3, and will show whether GSK was wise to hand over $625m for belrestotug in 2021. However, without defining what those predefined criteria were iTeos’s statement counts for little, and an accompanying $120m private placement – at a relatively depressed valuation done when iTeos is hardly strapped for cash – seems curious. The study includes a Jemperli monotherapy cohort in addition to the Keytruda comparator, so iTeos’s statement that “clinically meaningful tumour reduction” was seen “versus monotherapy” adds ambiguity. It’s still unclear why readout of Galaxies Lung-201, which isn’t event driven and tests ORR as primary endpoint, has been delayed from 2023, and why interim data still won’t be presented until the second half; even more strangely, GSK lists readout as a 2025 event. Given such opaqueness investors will be forgiven for recalling the bullish but ultimately disappointing claims about Gilead/Arcus’s rival anti-TIGIT MAb domvanalimab.