After AstraZeneca’s Imfinzi in late 2018 failed a trial in head and neck cancer, the company pinned its hopes on the phase 3 Kestrel study, figuring the drug might be able to show a benefit in patients with high levels of the PD-L1 biomarker.
But that study didn’t pan out. Friday, the British drugmaker said its checkpoint blocker had failed to show it could extend the lives of patients with previously untreated, PD-L1 high metastatic head and neck cancer when pitted against a standard-of-care treatment regimen.
A combo approach didn’t fare any better for AZ, which also reported that pairing Imfinzi with its investigational CTLA-4 treatment tremelimumab didn’t help patients live longer. In looking at that secondary endpoint, patients weren’t broken out by PD-L1 level.
“While we are disappointed by these results, insights from the Kestrel phase 3 trial will advance our understanding and application of immunotherapy across our clinical development program,” Dave Fredrickson, EVP and global head of AstraZeneca’s oncology business unit, said in a statement.
While the failure isn’t a huge financial blow to the company—SVBLeerink analysts modeled less than $150 million in potential peak U.S. and EU revenue from the indication—it still represents a few downsides for AstraZeneca, Leerink’s Geoffrey Porges wrote in a note to clients.
For one, it “could limit one of Imfinzi’s expansion opportunities outside the ‘safe harbor’ indication” it bears in stage 3 non-small cell lung cancer, by far Imfinzi’s largest source of revenue—and one that’s currently unchallenged by other members of the PD-1/PD-L1 class.
And speaking of those other members, the miss also “further diminishes the perceived profile” of Imfinzi versus Merck’s Keytruda, the checkpoint market leader, which scored an FDA green light in this head and neck cancer population after showing it could improve survival by 23% over the standard of care.
The final negative for AstraZeneca? It’s yet another study “that suggests limited incremental value” from tremelimumab, a drug that has yet to find a place in the market despite its inclusion in many trials.
AstraZeneca won’t have to wait long for a chance to redeem itself, though. It’s expecting results from a pair of phase 3 trials—Himalaya, which is examining the Imfinzi-tremelimumab combo in previously untreated liver cancer, and Poseidon, which is looking at its impact on lung cancer survival—later this year.