'Inadvertent' leak teases survival benefit for Roche's TIGIT

In an unusual development, Roche has put out a statement this morning acknowledging an "inadvertent disclosure" of data from its SKYSCRAPER-01 study of anti-TIGIT drug tiragolumab that points to an overall survival (OS) benefit.

The first interim analysis from the study of tiragolumab plus Roche's PD-L1 inhibitor Tecentriq (atezolizumab) in non-small cell lung cancer (NSCLC) was a bust, showing a trend to improvement in progression-free survival as first-line therapy for PD-L1-high advanced tumours compared to Tecentriq alone, which was not statistically significant.

At the time of that readout, Roche said it would continue to follow patients until the OS data matures. Now, due to the leak, it has revealed what at first glance looks like a possible win, with an estimate of 22.9 months for the combination arm and 16.7 months for Tecentriq.

The pharma stresses that the data were still not mature at the time of the second interim analysis, which took place in February and was based on a data cut-off in November 2022, around six months after it reported the first readout, with a median follow-up of 15.5 months.

Importantly, the hazard ratio came in at 0.81, with a p-value of 0.081, which doesn't cross the typical 0.05 threshold for statistical significance.

While the result is almost certainly premature and underpowered, it does provide a glimmer of hope for a positive outcome in the study, as well as for TIGIT as a target, which has seen a series of disappointing results in clinical trials, including the failure of Roche's SKYSCRAPER-02 study in extensive-stage small-cell lung cancer (ES-SCLC).

Meanwhile, in June, Novartis handed back rights to a TIGIT drug partnered with BeiGene in a deal that included a $300m upfront payment in 2021.

At this year's ASCO, however, there were some signs of a comeback, with positive results for tiragolumab in liver cancer, as well as for Gilead/Arcus' domvanalimab in NSCLC.

SKYSCRAPER-01's OS data is viewed as the next major inflection point for the category, and shares in Arcus, as well as other TIGIT developers such as iTeos Therapeutics, ticked up following the disclosure.

"SKYSCRAPER-01 is ongoing and the study remains blinded to patients and investigators," said Roche in its statement this morning. The circumstances surrounding the data disclosure have not been revealed.

"We are continuing the study until the final analysis for overall survival," it added. "All other studies in the tiragolumab programme will continue as planned."