A Real-World Experience of Cemiplimab in Patients with Advanced Cutaneous Squamous Cell Carcinoma.

Cutaneous squamous cell carcinoma (cSCC) represents the second most common form of non-melanoma skin malignancy, and, when not amenable to curative surgery or radiotherapy, it is a life-threatening disease. The anti-PD-1 monoclonal antibody cemiplimab has transformed the outcome of advanced or metastatic cSCC, with response rates approaching 50% and sustained benefit beyond three years in clinical trials. Cemiplimab is now the first-line standard of care treatment for advanced disease. This retrospective observational study included consecutive adult patients with locally advanced (lac) or metastatic (m) cSCC who received cemiplimab (350 mg every three weeks) at the Center for Immuno-Oncology, University Hospital of Siena, Italy, either through an Expanded Access Program or routine clinical practice. Clinical outcome and treatment related adverse events (TRAEs) are reported. Between December 2019 and December 2023, 27 patients (24 male; median age 82 years [range 41-90]) diagnosed with lacSCC (n = 20 [74.0%]) or mcSCC (n = 7 [25.9%]) were treated with cemiplimab as first line therapy and were followed until June 2024. Head and neck were the primary tumor location for 88.8% of patients, followed by trunk (7.4%) and lower extremities (3.7%). All patients had comorbidities, including six patients (22.2%) with hematologic malignancies. With a median follow-up of 31 months (data cut-off June 2024), the ORR was 66.6% (complete response 22.2%) and the disease control rate (DCR) 77.7%. Median progression-free survival (mPFS) and overall survival (mOS) were not reached, while 2-year PFS and OS rates were 65.2% and 71%, respectively. Treatment was well-tolerated, with three (11.1%) patients experiencing grade ≥3 TRAEs, and three patients discontinuing treatment due to TRAEs. Our real-world experience confirms the high rate of durable objective responses, good tolerability and long treatment duration of cemiplimab in elderly and frail cSCC patients as well.