Regeneron’s Libtayo has become the first checkpoint inhibitor to be cleared by the FDA as an adjuvant treatment for adults with cutaneous squamous cell carcinoma (CSCC) – a form of skin cancer – at high risk of recurrence after surgery and radiation therapy.
The US approval extends the use of Libtayo (cemiplimab) from its current indication in CSCC, approved in 2018, for treating patients with advanced disease who are not candidates for curative surgery and/or radiation. It has subsequently also picked up additional FDA approvals in basal cell carcinoma, non-small cell lung cancer, and cervical cancer.
The latest approval for adjuvant use in cSCC is significant for Regeneron, however, as it takes Libtayo into an area where it does not have to compete with other checkpoint inhibitors. That includes MSD’s market-leading Keytruda (pembrolizumab), which was unable to demonstrate efficacy as an adjuvant therapy for high-risk CSCC in the KEYNOTE-630 study.
There is a larger addressable patient population in the adjuvant setting compared to the advanced disease setting, where Libtayo is already considered the standard of care.
In the C-POST study that supported the new approval – which was a highlight of this year’s ASCO cancer conference – Libtayo achieved a 68% reduction compared to placebo in the risk of disease recurrence or death when given after surgery and radiotherapy for CSCC patients at high risk of disease recurrence due to factors like lymph node involvement.
At two years, 87% of Libtayo-treated patients remained disease-free, compared to 64% of those on placebo, and there were also trends towards an improvement in overall survival.
Libtayo was a relatively late entrant into the PD-1/PD-L1 inhibitor category but has grown steadily since launch and has latterly started to gather momentum, with sales rising 41% to $1.22 billion last year and reaching $662 million in the first six months of 2025.
“CSCC is one of the most common skin cancers in the world, with an estimated 1.8 million cases diagnosed each year in the U.S. alone,” said Samantha Guild, president of the AIM at Skin Cancer Foundation.
“While it can often be treated successfully with surgery and radiation, many patients face serious risk of advanced disease recurrences,” she added. “This approval is wonderful news for people living with CSCC, and we commend Regeneron for its long-standing commitment to addressing needs in non-melanoma skin cancer through its pioneering research.”
Libtayo has also been submitted for approval in Europe for the adjuvant CSCC indication, with a decision expected in the first half of 2026.
Top image Valerie Yanofsky/Stephen Mercer/Robert Phelps via Wikipedia
