A closely watched, experimental Roche medicine may be helping lung cancer patients live longer, spurring renewed optimism about an emerging class of immunotherapy treatments.
The data come from an interim analysis of a Phase 3 trial pairing the drug, tiragolumab, with a marketed Roche immunotherapy called Tecentriq in patients with non-small cell lung cancer. Roche completed the analysis in February, but never publicly disclosed its findings, which were inadvertently released on its website Tuesday night and discovered by Wall Street analysts. The company is expected to provide the final study results either late this year or early next.
The data shows that, after just over 15 months of follow-up, patients who received the drug combination had a 19% lower risk of dying than those who received Tecentriq alone. Specifically, at the time the analysis was performed, patients who got tiragolumab and Tecentriq lived a median of about 23 months, versus close to 17 months for Tecentriq recipients.
A graph showing the survival figures also showed a “clear and sustained separation” between the two groups, “which bodes well for a maintained clinical benefit” once the study’s final analysis is performed, wrote Leerink Partners analyst Daina Graybosch, in a note to investors on Wednesday.
However, it’s unclear how much benefit the drug might ultimately provide. Statistically, the reported reduction in relative risk wasn't great enough to judge the combination was superior. The tiragolumab combination already failed to slow tumor progression, the study’s other main goal. And because more than half the patients in both groups were still alive when the analysis was conducted, researchers weren’t able to conclusively measure the drug’s effects on survival, meaning the data are considered “immature.”
Nonetheless, the data appear to support Roche’s decision to put a greater statistical emphasis in measuring patients’ survival than tumor progression. The findings also lift the prospects of tiragolumab and other drugs like it, known collectively as TIGIT inhibitors because of their cellular target.
A lengthy list of large drugmakers and smaller biotechnology companies have invested heavily in TIGIT research, believing the drugs could help boost the effects of other immunotherapies. But the failure of tiragolumab in two lung cancer studies, along with a study setback reported by Merck & Co., seeded doubt about their potential.
Roche’s study in non-small cell lung cancer is viewed by analysts as important to assessing the future role, if any, TIGIT-blocking drugs will play in cancer care. Extending survival is the gold standard by which the Food and Drug Administration judges cancer drugs, meaning tiragolumab could have a chance at approval if Roche eventually reports a clear-cut benefit.
In a note to investors, Evercore ISI analyst Umer Raffat noted how the survival findings so far are “LAG-3 like,” referencing a class of immunotherapy drugs that saw its first approval last year. Leerink’s Graybosch added that the data “are clinically validating for TIGIT.”
The ripple effects of the findings were immediately felt by other companies. Shares in Arcus Biosciences, which is developing a TIGIT inhibitor with Gilead Sciences, jumped by 26%. Shares of GSK partner iTeos Therapeutics surged by more than 30%, while AstraZeneca collaborator Compugen climbed over 15%.
The results also have implications for Merck, which hopes its TIGIT-targeting drug can help extend the lucrative run for its top-selling cancer immunotherapy Keytruda. Merck’s medicine is expected to lose patent protection in 2028. The company is testing a drug that pairs Keytruda with a TIGIT inhibitor in a variety of tumor types.
Roche, meanwhile, has an extensive development program underway for tiragolumab. Tests are ongoing or planned in tumors of the cervix, esophagus and liver.