Cemiplimab as first intervention for patients with locally advanced cutaneous squamous cell carcinoma.

10065 Cemiplimab as First Intervention for Patients with Locally Advanced Cutaneous Squamous Cell Carcinoma (cSCC) Background: Cutaneous squamous cell carcinoma is the second most common non-melanoma skin cancer. Early stage disease is managed with local intervention in the form of surgery or radiation and translates into cure for greater than 95% of the patients. Patients with high risk disease who have large primary lesions, neural, or nodal involvement are usually not amenable to cure with local intervention and may experience significant morbidity, disfigurement, or functional deficits. These patients had no effective systemic treatment options until recent approval of cemiplimab. We report the outcomes for upfront treatment with cemiplimab in locally advanced cSCC. Methods: This is a single institution retrospective study of patients with locally advanced cSCC defined as those requiring more than simple excision and/or complex repair or regional disease with nodal involvement who received at least two doses of cemiplimab between January 1, 2018 through January 17, 2020. Patients with radiologically measurable disease had response evaluated per RECIST criteria. Patients who had no measurable disease had their clinical response (complete resolution or healing of primary lesion) assessed per treating physician and need or lack of local intervention documented. Adverse events were assessed and graded per CTCAE criteria. The primary end point was to ascertain the need for local intervention. Results: Thirty six patients were eligible. Twenty-two (61%) patients treated with upfront cemiplimab were able to avoid local intervention with surgery and/or radiation; four patients progressed or died on treatment. Three (8%) patients received local intervention. Eleven (31%) patients are still receiving cemiplimab and local intervention decision is pending. The overall response rate was 69% and the clinical benefit rate was 92%. The median treatment duration was six months and the median number of doses received was six. Adverse events occurred in 31% of patients; the most common adverse event was dermatitis. Conclusions: Upfront treatment with cemiplimab in patients with locally advanced cSCC obviated need for disfiguring/complex surgery or radiation in majority of patients. Cemiplimab was tolerated well; no new safety signals were observed. Neo-adjuvant phase II study is in development.