FDA

Libtayo OK’d for adjuvant treatment of cutaneous squamous cell carcinoma

October 16, 2025

On October 8, 2025, FDA approved the PD-1 inhibitor Libtayo (cemiplimab-rwlc) as an adjuvant treatment for adults with cutaneous squamous cell carcinoma (CSCC) at high risk of recurrence after surgery and radiation.

Efficacy

Efficacy was evaluated in the randomized, double-blind, multicenter, placebo-controlled C-POST trial (NCT03969004) involving 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. Participants 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 wasn’t reached in the cemiplimab-rwlc arm (95% confidence interval [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).

Safety

The most common adverse reactions reported in the trial were rash (37%), pruritus (16%), and hypothyroidism (12%).

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 dose

The recommended dosage of Libtayo is 350 mg IV 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 of total therapy.

Sources:

FDA approves cemiplimab-rwlc for adjuvant treatment of cutaneous squamous cell carcinoma. [News release]. 2025. https://www.fda.gov/drugs/resources-information-approved-drugs/fda-approves-cemiplimab-rwlc-adjuvant-treatment-cutaneous-squamous-cell-carcinoma

Libtayo (cemiplimab-rwlc) [package insert]. Food and Drug Administration. https://www.accessdata.fda.gov/drugsatfda_docs/label/2025/761097s030lbl.pdf Revised October 2025. Accessed October 15, 2025.

Libtayo® (cemiplimab-rwlc) approved in the US as first and only immunotherapy for adjuvant treatment of cutaneous squamous cell carcinoma (CSCC) with a high risk of recurrence after surgery and radiation. [News release]. 2025. https://investor.regeneron.com/news-releases/news-release-details/libtayor-cemiplimab-rwlc-approved-us-first-and-only