On October 17, 2025 Regeneron Pharmaceuticals, Inc. (NASDAQ: REGN) reported that the European Medicines Agency’s (EMA) Committee for Medicinal Products for Human Use (CHMP) has adopted a positive opinion for Libtayo (cemiplimab) as an adjuvant treatment for adult patients with cutaneous squamous cell carcinoma (CSCC) at high risk of recurrence after surgery and radiation. The European Commission is expected to make a final decision on the application in the coming months. Libtayo was approved by the U.S. Food and Drug Administration (FDA) for these patients in the U.S. earlier this month.
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The positive opinion is supported by results from the global Phase 3 C-POST trial investigating adjuvant Libtayo versus placebo in patients with CSCC at high risk of recurrence following surgery and radiation. In the trial, Libtayo reduced the risk of disease recurrence or death by 68% compared to placebo (hazard ratio [HR]: 0.32; 95% confidence interval [CI]: 0.20-0.51; p<0.0001). Fewer patients treated with Libtayo had locoregional or distant recurrence compared with those who received placebo (4% vs. 17% and 5% vs. 13%, respectively). Detailed data were published in the New England Journal of Medicine (NEJM) in May 2025.
The safety profile of Libtayo as adjuvant treatment of patients with CSCC at high risk of recurrence after surgery and radiation is consistent with the known safety profile for Libtayo monotherapy in advanced cancers. In the trial, adverse events (AEs) occurred in 91% of patients receiving Libtayo (n=205) and 89% of patients receiving placebo (n=204). Grade ≥3 AEs occurred in 24% and 14% of patients in the Libtayo arm and the placebo arm, respectively. The most common AEs occurring in at least 10% of patients who received Libtayo were fatigue, pruritus, rash, diarrhea, arthralgia, hypothyroidism and maculo-papular rash. The only grade ≥3 AE that occurred in more than 2% of patients in the Libtayo arm was hypertension. AEs led to permanent discontinuation of treatment in 10% of patients who received Libtayo and 2% of patients who received placebo. Two patients in each arm experienced an AE leading to death.
About the Phase 3 Trial
C-POST was a randomized, placebo-controlled, double-blind, multicenter, global Phase 3 trial investigating Libtayo versus placebo as adjuvant treatment for patients with features associated with a high risk of CSCC recurrence and who had completed surgery and post-operative radiation therapy. Trial participants were at high risk of recurrence due to nodal features (extracapsular extension or ≥3 involved lymph nodes) and/or non-nodal features (in-transit metastases, T4 lesion, perineural invasion, or locally recurrent tumor with ≥1 additional poor prognostic features).
The trial enrolled 415 patients who were randomized to receive either Libtayo (n=209) or placebo (n=206) for up to 48 weeks. For the first 12 weeks, Libtayo 350 mg or placebo was administered intravenously every three weeks, followed by Libtayo 700 mg or placebo administered intravenously every six weeks for 36 weeks.
About CSCC
Cutaneous squamous cell carcinoma (CSCC) is a type of non-melanoma skin cancer (NMSC), and one of the most common cancers in the world. In the EU, the incidence of NMSC overall is expected to increase by 40% by 2040. CSCC can often be treated successfully with surgery, but many patients may have a "high risk" form that is more aggressive, and they face an increased risk of recurrence and disease progression.
(Press release, Regeneron, OCT 17, 2025, View Source [SID1234656777])