Six Months On Gilead/Arcus’s TIGIT Deflates
The run-up to this year’s ASCO meeting saw a remarkable resurgence of interest in the TIGIT mechanism, but the 3 June update on Gilead/Arcus’s Arc-7 study in NSCLC could puncture the enthusiasm. With 7.4 months’ additional median follow-up, and six more patients in each cohort, the PFS data for domvanalimab plus zimberelimab have deteriorated versus zimberelimab monotherapy. The anti-Tigit/PD-1 doublet that at December’s ASCO virtual plenary had shown a 45% reduction in risk of progression or death, and a 6.6-month increase in median PFS versus the Arcus PD-1 alone, now stands at a 33% reduction and 3.9-month delta, the new ASCO update revealed. Not only that, but the confidence interval upper bound is now 1.13, having earlier stood precariously at 1.00 exactly. True, the shape of the PFS curves and small numbers of patients make it evident that just one or two early progressers might be making the difference. But the meaningfulness of Arc-7 was already in doubt, and the optics of a dataset that is clearly not improving will not go down well with fickle investors.
After Arcus/Gilead’s TIGIT data shocked at the start of the American Society of Clinical Oncology annual meeting, Roche brought another bombshell. Roche’s fact-finding mid-stage Morpheus-liver trial, which had sent Tigit-fixated investors’ pulses racing a week ago, has delivered a strong enough signal for a phase 3 trial to be launched, ASCO learned 4 June.
Presenting the Morpheus-liver data in full, UCLA’s Dr Richard Finn outlined a global, placebo-controlled study, Imbrave-152/Skyscraper-14, that would pit tiragolumab,...
