Libtayo® (cemiplimab-rwlc) Receives U.S. FDA Approval As The First And Only Immunotherapy For Adjuvant Treatment Of High-Risk CSCC After Surgery And Radiation

Regeneron Pharmaceuticals, Inc. has announced that the U.S. Food and Drug Administration (FDA) has approved its PD-1 inhibitor Libtayo (cemiplimab-rwlc) as an adjuvant treatment for adult patients with cutaneous squamous cell carcinoma (CSCC) who are at high risk of recurrence after surgery and radiation therapy. The approval was granted under the FDA’s Priority Review program, which is reserved for treatments offering significant advances in the management of serious conditions. A regulatory review for the same indication is also underway in the European Union, with a decision expected in the first half of 2026.

This approval marks a major advancement for patients with high-risk CSCC, who previously had limited options to prevent disease recurrence following surgery and radiation. Libtayo is now the first and only immunotherapy approved in the adjuvant setting for these patients. The FDA’s decision was based on results from the pivotal Phase 3 C-POST trial, which compared adjuvant Libtayo to placebo in patients with CSCC at high risk of recurrence. Findings from the study, published in the New England Journal of Medicine and presented at the 2025 ASCO Annual Meeting, showed that Libtayo reduced the risk of disease recurrence or death by 68% compared with placebo (hazard ratio [HR]: 0.32; 95% CI: 0.20–0.51; p<0.0001).

Libtayo demonstrated a safety profile consistent with its known use in advanced cancers. The most common side effects (≥10% and ≥3% higher than placebo) included rash, itching (pruritus), and hypothyroidism. Serious adverse reactions occurred in 18% of patients, with pneumonia, rash, diarrhea, adrenal insufficiency, and arrhythmia being reported in 1% or more of cases. Regeneron’s President and Chief Scientific Officer, Dr. George D. Yancopoulos, emphasized that this approval establishes Libtayo as the only immunotherapy proven effective for preventing recurrence in high-risk CSCC, reinforcing its role as a leading PD-1 inhibitor across multiple cancer types.

Cutaneous squamous cell carcinoma is among the most common skin cancers globally, with an estimated 1.8 million new cases each year in the United States alone. While most cases can be treated with surgery and radiation, many patients remain at risk of advanced recurrences. To support patient access, Regeneron has introduced Libtayo Surround™, a program offering financial assistance and educational resources to help patients throughout their treatment. Patients seeking support can contact 1-877-LIBTAYO (1-877-542-8296). The supplemental Biologics License Application (sBLA) approved by the FDA did not include Catalent Indiana, LLC as a filling site.