The U.S. Food and Drug Administration (FDA) has granted approval to the PD-1 inhibitor Libtayo (cemiplimab-rwlc) for use as an adjuvant treatment in adult patients with cutaneous squamous cell carcinoma (CSCC) who are at a high risk of recurrence following definitive surgery and radiation, according to an announcement by Regeneron Pharmaceuticals, Inc.

This FDA decision, evaluated under Priority Review due to its potential for significant therapeutic improvement, marks Libtayo as the first and only immunotherapy to be approved for patients in this earlier setting, fundamentally changing the current treatment paradigm where immunotherapy was previously reserved only for advanced CSCC cases. The approval is a significant breakthrough for patients who often face the poorest outcomes due to their high risk of the disease recurring, a fact highlighted by experts who note that many patients are confirmed as high-risk only after post-surgical pathological evaluation. Regeneron is also pursuing a similar regulatory application in the European Union, with a decision anticipated by the first half of 2026.

The foundation for this landmark approval rests on the compelling data from the pivotal Phase 3 C-POST trial, which compared adjuvant Libtayo to placebo. The study's results, published in the New England Journal of Medicine, met its primary endpoint by demonstrating that Libtayo significantly reduced the risk of disease recurrence or death by 68% compared to placebo, reporting a highly statistically significant hazard ratio of 0.32 (p<0.0001). This clinical benefit firmly establishes the drug as an efficacious option for preventing a devastating recurrence in this population. The safety profile of Libtayo in the adjuvant CSCC setting was consistent with its known profile in advanced cancers, with the most common adverse reactions being rash, pruritus, and hypothyroidism. To ensure patient support, Regeneron has launched Libtayo Surround™, a program offering financial and educational resources. This new indication solidifies Libtayo’s versatility, building on its four existing FDA approvals for various advanced cancers, and underscores Regeneron's commitment to addressing the needs in non-melanoma skin cancer.