FDA approves cemiplimab-rwlc for adjuvant treatment of cutaneous squamous cell carcinoma

On Oct 8, 2025, the FDA approved cemiplimab-rwlc (Libtayo) for adjuvant treatment of adults with cutaneous squamous cell carcinoma (CSCC) at high risk of recurrence after surgery and radiation. Approval was supported by the phase 3 C-POST trial (NCT03969004), which showed improved disease-free survival versus placebo (HR 0.32; p<0.0001). Labeling includes warnings for immune-mediated adverse reactions, infusion-related reactions, HSCT complications, and embryo-fetal toxicity.

Type: Regulatory approval (FDA)

Date: 2025-10-08

The FDA 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.

Supporting evidence (C-POST; NCT03969004)

  • Design: Randomized, double-blind, multicenter, placebo-controlled trial
  • Population: 415 patients with CSCC at high risk of recurrence after surgery and radiation; adjuvant radiation had to be completed 2–10 weeks before randomization
  • Key exclusions: Autoimmune disease requiring systemic immunosuppressants within 5 years; history of solid organ transplant; prior allogeneic/autologous stem cell transplant; uncontrolled HIV; hepatitis B or C infection; ECOG ≥2
  • Randomization: 1:1 cemiplimab-rwlc vs placebo
  • Primary endpoint: Disease-free survival (DFS)

DFS results: Median DFS was not reached with cemiplimab-rwlc (95% CI: NE, NE) vs 49.4 months with placebo (95% CI: 48.5, NE); HR 0.32 (95% CI: 0.20–0.51); p<0.0001.

Safety and dosing (per prescribing information)

Warnings/precautions include immune-mediated adverse reactions, infusion-related reactions, complications of allogeneic hematopoietic stem cell transplantation, and embryo-fetal toxicity.

Recommended dosage: 350 mg IV every 3 weeks for 12 weeks then 700 mg every 6 weeks, or 350 mg every 3 weeks, until recurrence, unacceptable toxicity, or up to 48 weeks.

The review used Real-Time Oncology Review and priority review pathways.

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