When Regeneron and Sanofi won FDA approval for their anti-PD-1 cancer drug Libtayo in 2018, they were late to a market that was already dominated by the likes of Merck & Co.’s Keytruda. But now the companies are trying to forge a brand-new market for PD-1 inhibitors—and they just posted data that could help.
The companies have been testing Libtayo solo in basal cell carcinoma patients with locally advanced disease who've stopped responding or are intolerant to hedgehog pathway inhibitors like Roche’s Erivedge. In a pivotal trial reported at the virtual meeting of the European Society of Clinical Oncology (ESMO), Libtayo prompted a response in 31% of them, Regeneron and Sanofi said. At the one-year mark, 85% of those patients were still responding.
Median overall survival was not yet reached in the trial, but the companies estimated the probability of survival to be 92%.
“This is a horribly disfiguring disease in the advanced stage. We’ve seen some amazing improvements in patients,” Israel Lowy, Regeneron's SVP of translational and clinical science in oncology, said in an interview.
The trial patients had already exhausted other treatment options beyond hedgehog inhibitors, such as surgery and radiation, Lowy added, so Libtayo might “offer an opportunity at what was previously a dead end."
Regeneron and Sanofi are preparing to submit Libtayo for approval in basal cell carcinoma later this year. It would be the drug's second green light in skin cancer, after an initial nod in cutaneous squamous cell carcinoma.
The companies also have an ambitious development plan for Libtayo beyond skin cancer. They plan to report data from a trial in non-small cell lung cancer (NSCLC) later during the ESMO meeting, and they're testing the drug in melanoma, colorectal cancer, Hodgkin lymphoma and other tumor types, both alone and as part of combination treatments.
Despite being late to the PD-1 party, Regeneron and Sanofi have generated a fair amount of enthusiasm for Libtayo on Wall Street. Bernstein analysts predicted earlier this year that sales of the drug will eventually hit $2 billion.
Patients with basal cell carcinoma typically have tumors with a high “mutational burden,” which can predict a strong response to immuno-oncology drugs, Lowy said. The biomarker PD-L1 is sometimes measured in patients to determine who will respond best to PD-1 inhibitors, but in this trial “it didn’t matter what the PD-L1 level was at baseline,” Lowy said. “Everybody benefited.”