Libtayo® (cemiplimab) Phase 3 Data in the Adjuvant Treatment of Post-Surgical High-Risk Cutaneous Squamous Cell Carcinoma (CSCC) Have Potential to Be Practice-Changing

Core Insights - Libtayo (cemiplimab) has shown a 68% reduction in the risk of disease recurrence or death in high-risk cutaneous squamous cell carcinoma (CSCC) patients after surgery, with significant reductions in locoregional (80%) and distant recurrence (65%) compared to placebo [1][5][6] - The Phase 3 C-POST trial results were presented at the 2025 ASCO Annual Meeting and published in the New England Journal of Medicine, establishing Libtayo as the first immunotherapy to demonstrate a statistically significant benefit in the adjuvant setting for high-risk CSCC [2][4] - Regulatory applications for Libtayo have been submitted in the United States and European Union for the treatment of adjuvant CSCC [1][7] Group 1: Trial Results - The C-POST trial was a randomized, placebo-controlled, double-blind study involving 415 patients, with 209 receiving Libtayo and 206 receiving placebo [9][10] - The median duration of follow-up was 24 months, with updated overall survival (OS) data suggesting an emerging benefit for Libtayo (HR: 0.78; 95% CI: 0.39-1.56) [3] - Disease-free survival (DFS) at two years was 87% for Libtayo versus 64% for placebo, with median DFS not reached for Libtayo-treated patients [5] Group 2: Safety and Efficacy - Safety assessments indicated that adverse events (AEs) of any grade occurred in 91% of patients in the Libtayo arm, with grade ≥3 AEs occurring in 24% [6] - The most common AEs in the Libtayo arm included fatigue, pruritus, rash, diarrhea, and hypothyroidism, with treatment discontinuations due to AEs at 10% for Libtayo compared to 2% for placebo [6] - An exploratory analysis showed that Libtayo reduced the risk of disease recurrence or death by 72% in tumors with PD-L1 ≥1% and by 68% in tumors with PD-L1 <1% [4] Group 3: Industry Context - The results from the C-POST trial highlight the critical unmet need for systemic therapies in high-risk CSCC, as surgery and radiotherapy remain the primary treatments [2] - Libtayo's promising results position it as a potential new standard of care in the adjuvant setting for high-risk CSCC patients [4] - Regeneron is actively working with global regulatory authorities to expedite the availability of Libtayo for patients [4]