Libtayo® Gains FDA Approval as First Adjuvant PD-1 Therapy for High-Risk Cutaneous Squamous Cell Carcinoma
The FDA has approved cemiplimab-rwlc (Libtayo®) for adjuvant treatment of adults with high-risk cutaneous squamous cell carcinoma after surgery and radiation. Libtayo is already approved for advanced CSCC, basal cell carcinoma, and NSCLC.
On October 8, 2025, the U.S. Food and Drug Administration (FDA) approved cemiplimab-rwlc (Libtayo®, developed by Regeneron) for the adjuvant treatment of adults with cutaneous squamous cell carcinoma (CSCC) at high risk of recurrence after surgery and radiation.
Libtayo, a PD-1 inhibitor, was previously approved for advanced CSCC, basal cell carcinoma, and non-small cell lung cancer, and this latest approval extends its reach into the adjuvant setting, marking another major milestone for Regeneron’s immuno-oncology portfolio.
Efficacy and Safety
- Clinical Study:
Approval was based on the C-POST trial (NCT03969004), a randomized, double-blind, multicenter, placebo-controlled study of 415 patients with high-risk CSCC. Patients received adjuvant radiation therapy 2–10 weeks prior to randomization. Key exclusion criteria included autoimmune disease requiring systemic immunosuppressants within 5 years, prior organ or stem cell transplant, uncontrolled HIV or hepatitis B/C, and ECOG performance status ≥2. - Efficacy Outcome:
The primary endpoint was disease-free survival (DFS). Median DFS was not reached in the cemiplimab arm versus 49.4 months in the placebo arm (Hazard Ratio 0.32; 95% CI: 0.20–0.51; p<0.0001), demonstrating a 68% reduction in the risk of recurrence or death. - Safety Profile:
Warnings include immune-mediated adverse reactions, infusion-related reactions, complications in patients with prior allogeneic hematopoietic stem cell transplant, and embryo-fetal toxicity. Common adverse events were fatigue, rash, diarrhea, and musculoskeletal pain. - Recommended Dosage:
- Option 1: 350 mg IV every 3 weeks for 12 weeks, followed by 700 mg every 6 weeks
- Option 2: 350 mg IV every 3 weeks until disease recurrence, unacceptable toxicity, or up to 48 weeks
Other FDA-Approved Indications for Cemiplimab (Libtayo®)
| Indication | FDA Approval Year |
|---|---|
| Advanced or metastatic cutaneous squamous cell carcinoma | 2018 |
| Locally advanced basal cell carcinoma (patients ineligible for or progressed on Hedgehog inhibitors) | 2021 |
| Non-small cell lung cancer (NSCLC) with PD-1 therapy ± platinum-based chemotherapy | 2022 |
| Adjuvant therapy for high-risk CSCC | 2025 |