Adjuvant Libtayo® (cemiplimab) Significantly Improves Disease-Free Survival (DFS) After Surgery in High-Risk Cutaneous Squamous Cell Carcinoma (CSCC) in Phase 3 Trial

Clinical Trial Results - Libtayo demonstrated a 68% reduction in the risk of disease recurrence or death in high-risk CSCC patients compared to placebo, meeting the primary endpoint of DFS at the first prespecified interim analysis [1][2] - The Phase 3 C-POST trial enrolled 415 patients with high-risk CSCC, randomized to receive Libtayo or placebo for up to 48 weeks, with a median follow-up duration of 24 months [2] - Libtayo is the first and only immunotherapy to show a statistically significant and clinically meaningful benefit in high-risk CSCC in the adjuvant setting, following a recent Phase 3 trial with Keytruda that failed in the same setting [1] Safety Profile - Adverse events of any grade occurred in 91% of patients in the Libtayo arm and 89% in the placebo arm, with Grade ≥3 AEs occurring in 24% and 14% of patients, respectively [3] - Treatment discontinuations due to adverse reactions occurred in 10% of patients in the Libtayo arm and 1.5% in the placebo arm, with two patients experiencing an AE leading to death in each arm [3] Regulatory and Market Impact - Libtayo is already the standard of care for certain patients with advanced CSCC and has been approved in more than 30 countries for various indications, including advanced BCC, CSCC, NSCLC, and cervical cancer [5][25] - The company plans to submit the trial results to the U.S. FDA in the first half of 2025, with detailed results to be presented at an upcoming medical meeting [20] Company Background and Technology - Regeneron's VelocImmune technology, which utilizes a genetically engineered mouse platform, was instrumental in developing Libtayo and other FDA-approved fully human monoclonal antibodies [26] - The company's oncology strategy includes a robust pipeline with nearly half of its assets in clinical development, focusing on checkpoint inhibitors, bispecific antibodies, and costimulatory bispecific antibodies [16] Trial Design and Methodology - The C-POST trial is a randomized, placebo-controlled, double-blind, multicenter Phase 3 study investigating Libtayo as adjuvant treatment for high-risk CSCC patients who have completed surgery and post-operative radiation therapy [22] - The trial design includes a primary endpoint of DFS and secondary endpoints such as freedom from locoregional recurrence, freedom from distant recurrence, overall survival, and cumulative incidence of second primary CSCC tumors [24]