In 2022, Regeneron paid Sanofi $900 million to gain full rights to its partnered cancer drug Libtayo. Three years later, the pricey bet on the injected PD-1 inhibitor appears to be paying off.
Thursday, the FDA approved Libtayo as the first immunotherapy for adjuvant treatment of cutaneous squamous cell carcinoma (CSCC). The nod applies to patients who are at a high risk of recurrence after surgery and radiation.
The green light comes seven years after Libtayo became the first drug to reach the market in CSCC, as it was endorsed for patients with metastatic CSCC or those with locally advanced CSCC who are not candidates for surgery or curative radiation.
The patient population is significant; approximately 1.8 million are diagnosed annually in the U.S. with CSCC, accounting for roughly 20% of the nation's skin cancer cases.
Regeneron has an application under review in Europe in the same indication, with a decision expected in the first half of 2026.
“Patients whose CSCC is at a high risk of recurrence following surgery and radiation often have the poorest outcomes," Vishal Patel, M.D., professor of dermatology at George Washington University, said in a release. "Until now, we lacked options to help prevent a devastating recurrence and immunotherapy was only available for patients with advanced CSCC, who were no longer candidates for curative surgery or curative radiation."
Patel added that the label expansion is “practice-changing” for the at-risk patient group.
The approval was based on a phase 3 trial that showed Libtayo reduced the risk of disease recurrence or death by 68% compared to placebo at a median follow up of 24 weeks.
Particularly noteworthy about the result was that Libtayo succeeded where Merck’s PD-1 powerhouse Keytruda had failed. A year ago, because of futility, Merck discontinued a trial of Keytruda as an adjuvant treatment for patients with high-risk locally advanced CSCC following surgery and radiation.
Libtayo has been on a steady uptick in recent years. A few months after Regeneron secured sole possession of the medicine, the FDA signed off on a label expansion for Libtayo in combination with chemotherapy as a first-line treatment for advanced non-small cell lung cancer.
Last year, Libtayo achieved blockbuster sales for the first time, generating $1.22 billion. Another increase is assured this year as second-quarter worldwide sales were up 27% year over year to $377 million.
Regeneron also is studying Libtayo as a combo therapy with the company’s own fianlimab in first-line melanoma, where the regimen is going up against Keytruda.
“If these data confirm best-in-class activity in melanoma, it will increase our confidence for this combination in other cancer settings,” Regeneron Chief Scientific Officer George Yancopoulos, M.D., Ph.D., said during the company’s second-quarter earnings call.