Real-Life Study of the Benefit of Concomitant Radiotherapy with Cemiplimab in Advanced Cutaneous Squamous Cell Carcinoma (cSCC): A Retrospective Cohort Study.

backgroundCemiplimab is a monoclonal antibody targeting the PD-1, and phase II trials have shown its efficacy in the treatment of advanced cutaneous squamous cell carcinoma in patients who are not candidates for curative surgery or radiation therapy as a first- or later-line treatment. A synergistic antitumoral response has been demonstrated with concurrent radiotherapy and PD1-immunotherapy. However, no real-life study has demonstrated this effect in advanced cutaneous squamous cell carcinoma.

methodsWe conducted a real-life retrospective cohort study to investigate the benefit of concomitant therapy in 33 patients treated with cemiplimab at the University Hospital of Caen, alone (C group) or concomitant to radiotherapy (C/RT group). Our primary objectives were to evaluate the best overall response and objective response rate. Our secondary objectives were the disease control rate, median time to response, progression-free survival, overall survival, clinical benefit of radiotherapy, and safety data. After stopping cemiplimab administration, we performed a follow-up of our patients and performed a descriptive study.

resultsWe reported an objective response rate of 45.5%, including 47.6% in the cemiplimab group versus 41.6% in the concomitant group. The addition of radiotherapy to cemiplimab enables an earlier clinico-radiological response, with a median duration of 5.5 months in the cemiplimab group versus 3 months in the concomitant therapy group. The response to treatment was prolonged despite discontinuation of cemiplimab, with 91.6% (

conclusionsOur study confirms the efficacy of cemiplimab and radiotherapy in the management of advanced cutaneous squamous cell carcinoma. Concomitant therapy permitted to obtain an earlier radiological response, a beneficial local therapeutic effect of radiotherapy, without any safety alert.