1372TiPA phase III, randomised, double-blind study of adjuvant cemiplimab versus placebo post-surgery and radiation in patients with high-risk cutaneous squamous cell carcinoma (CSCC)

Abstract Background CSCC is the second most common skin cancer. While the surgical cure rate for CSCC is > 95%, a proportion of pts are considered to have high-risk for recurrence as assessed by immune status, primary disease stage, extent of nodal involvement, presence of extracapsular extension, and prior treatment. Post-operative RT is recommended for pts with high-risk features, but relapse with locoregional recurrence or distant metastases may still occur. This study evaluates the efficacy of cemiplimab, a human anti–PD-1 monoclonal antibody, as an adjuvant therapy for pts with CSCC with high-risk features, after surgery and RT. Trial design This randomised, placebo-controlled, double-blind, multicentre, Phase III study will evaluate cemiplimab as an adjuvant treatment for pts with high-risk CSCC, based on surgical and clinicopathologic findings, who have completed surgery and post-operative RT. Immunocompromised pts were excluded. The trial will enrol 412 pts from about 100 sites in North America, Europe, and Asia-Pacific regions. Pts with at least one of the following high-risk features are eligible: a) nodal disease with extracapsular extension b) in-transit metastases c) T4 lesion d) perineural invasion and e) recurrent CSCC with at least one other risk factor. In Part 1 (blinded), pts will be randomised 1:1 to receive 350 mg cemiplimab or placebo intravenously every 3 weeks (Q3W) for up to 48 weeks. In optional Part 2 (unblinded), pts in the placebo arm who experience disease recurrence or pts in the cemiplimab arm who experience disease recurrence ≥3 months after completion of 48-week treatment in Part 1 will be eligible to receive open-label 350 mg Q3W cemiplimab for up to 96 weeks. Key objectives are to compare disease-free survival (primary) as well as overall survival, freedom from locoregional relapse, and distant relapse (secondary) of adjuvant cemiplimab vs placebo in pts with high-risk CSCC. Editorial acknowledgement Medical writing support and typesetting was provided by Bu Reinen of Prime, Knutsford, UK, funded by Regeneron Pharmaceuticals, Inc., and Sanofi. Legal entity responsible for the study Regeneron Pharmaceuticals, Inc., and Sanofi. Funding Regeneron Pharmaceuticals, Inc., and Sanofi. Disclosure D. Rischin: Research grant / Funding (institution), Non-remunerated activity/ies: Regeneron Pharmaceuticals, Inc.; Research grant / Funding (institution), Non-remunerated activity/ies: GSK; Research grant / Funding (institution), Travel