Roche posts interim TIGIT overall survival data after 'inadvertent disclosure,' sending stocks up

An “inadvertent disclosure” has given the world a look at Roche’s eagerly anticipated TIGIT data. Having kept its cards close to its chest throughout the phase 3 lung cancer study, the Swiss drugmaker published interim overall survival results Wednesday after they were mistakenly made public.

The data drop comes from Roche’s SKYSCRAPER-01, a phase 3 trial that is testing the anti-TIGIT antibody tiragolumab in combination with the checkpoint inhibitor Tecentriq in first-line non-small cell lung cancer (NSCLC) patients. Roche revealed that adding tiragolumab to Tecentriq failed to improve progression-free survival (PFS) last year, causing the study to miss one co-primary endpoint, but never shared numbers. 

Earlier this year, Roche said the clinical trial had continued past an interim analysis of its overall survival (OS) endpoint. The update confirmed that the interim OS data were neither so good nor so bad that the trial needed stopping, but beyond that said nothing about the chances of success in the final analysis. 

Now, Roche has shared the results of the second interim analysis that took place in February. As of the cutoff in November 2022, estimated median overall survival in the tiragolumab combination arm was 22.9 months, compared to 16.7 months in the Tecentriq monotherapy cohort. The hazard ratio was 0.81. Median follow-up at the time of the analysis was 15.5 months. 

The interim analysis shows people on tiragolumab are living longer, albeit not by an amount that was big enough to be statistically significant as of the November cutoff. The final analysis, which is scheduled for the third quarter, remains the key event that will determine whether Roche can recover from its PFS fail and get tiragolumab to market in NSCLC.

Roche’s OS data leak has increased investor confidence. Shares in Roche rose 4.5% to 264 Swiss francs ($300) in early trading in Switzerland in the hours after the release of the data.

The data dragged other TIGIT stocks up, too, with shares in Arcus Biosciences and iTeos Therapeutics rising more than 20% premarket as the interim analysis reignited investor interest in a target that has largely underwhelmed to date.

Analysts at Evercore heralded the unintended readout as “very good data.”

“If you look at the curves, they are expanding,” the Evercore analysts wrote in a Wednesday morning note. “In other words, it is possible that by the time final analysis happens, hazard ratio has improved to just under 0.8.”

J.P.Morgan analysts also noted that the latest findings “suggest … the trial could still be statistically significant at the final analysis.” However, they added that the “detailed data” didn’t change their overall view on tiragolumab’s potential.

“The clinical relevance of the benefit shown by the TIGIT combination is likely to be debated, which means that the product is unlikely to be commercially significant,” the analysts said.

Meanwhile, analysts at Leerink Partners said it remained “unclear to us whether tira[golumab]’s relative benefit will improve enough to meet SKY-01’s stringent statistical boundary.”