Phase II Study of Neoadjuvant Cemiplimab for Stage II to IV Cutaneous Squamous Cell Carcinoma: Final Analysis

We previously reported the results of a multicenter phase II trial (ClinicalTrials.gov identifier: NCT04154943 ) of neoadjuvant cemiplimab in resectable stage II to IV cutaneous squamous cell carcinoma (CSCC), in which the pathologic complete response (pCR) rate was 51%. At the 19-month follow-up, estimated 12-month event-free survival (EFS) was 89%, with 11 EFS events. In this study, we report final EFS and overall survival (OS) at a median follow-up of 54 months. Overall, 16 EFS events occurred at final analysis. There were no new disease recurrence events. The five new EFS events were all comorbidity-related deaths without CSCC recurrence. Overall estimated 54-month EFS was 76.2% (81.5% in patients with pCR, 88.9% in patients with major pathologic response, 100% in patients with partial pathologic response, and 45.7% in nonresponders/not-evaluable patients). Among 40 patients with pCR, none had experienced disease recurrence. Overall estimated 54-month OS was 79.4%. No new grade ≥3 treatment-emergent adverse events occurred. The final analysis demonstrates durable EFS and OS, no late recurrences, and no new safety signals with neoadjuvant cemiplimab.