On October 8, 2025, the Food and Drug Administration approved cemiplimab-rwlc (Libtayo, Regeneron Pharmaceuticals Inc.) for the adjuvant treatment of adults with cutaneous squamous cell carcinoma (CSCC) at high risk of recurrence after surgery and radiation.

Full prescribing information for Libtayo will be posted on Drugs@FDA.

Efficacy and Safety

Efficacy was evaluated in C-POST (NCT03969004), a randomized, double-blind, multicenter, placebo-controlled trial in 415 patients with CSCC at high risk of recurrence after surgery and radiation. Patients were required to complete adjuvant radiation therapy within two to 10 weeks of randomization. The study excluded patients with autoimmune disease requiring systemic immunosuppressant agents within five years, a history of solid organ transplant, prior allogeneic or autologous stem cell transplantation, uncontrolled HIV, hepatitis B or hepatitis C infection, or an Eastern Oncology Group performance status ≥ 2. Patients were randomized (1:1) to receive cemiplimab-rwlc or placebo.

The major efficacy outcome measure was disease-free survival (DFS) defined as the time from randomization to the first documented disease recurrence by investigator assessment or death due to any cause. Median DFS was not reached in the cemiplimab-rwlc arm (95% CI: not evaluable [NE], NE) and 49.4 months (95% CI: 48.5, NE) in the placebo arm (Hazard ratio 0.32 [95% CI: 0.20, 0.51]; p-value <0.0001).

The prescribing information includes warnings and precautions for immune-mediated adverse reactions, infusion-related reactions, complications of allogeneic hematopoietic stem cell transplantation, and embryo-fetal toxicity.

Recommended Dosage

The recommended dose is 350 mg intravenously every three weeks for 12 weeks, followed by 700 mg every six weeks, or 350 mg every three weeks until disease recurrence, unacceptable toxicity, or up to 48 weeks.

Expedited Programs

This review used the Real-Time Oncology Review pilot program, which streamlined data submission prior to the filing of the entire clinical application, and the Assessment Aid, a voluntary submission from the applicant to facilitate the FDA’s assessment.

This application was granted priority review. FDA expedited programs are described in the Guidance for Industry: Expedited Programs for Serious Conditions-Drugs and Biologics.

Healthcare professionals should report all serious adverse events suspected to be associated with the use of any medicine and device to FDA’s MedWatch Reporting System or by calling 1-800-FDA-1088.

For assistance with single-patient INDs for investigational oncology products, healthcare professionals may contact OCE’s Project Facilitate at 240-402-0004 or email OncProjectFacilitate@fda.hhs.gov.

Follow the Oncology Center of Excellence on X: @FDAOncology.