Chemo-immunotherapy in Patients With Resectable Merkel Cell Carcinoma Prior to Surgery

This is a window-of-opportunity study for patients with resectable Merkel Cell Carcinoma. The aim of this study is to test the activity of a course of chemo-immunotherapy followed by surgery in patients with operable Merkel cell carcinoma. Participants will receive one cycle of retifanlimab plus platinum-etoposide chemotherapy prior to their scheduled surgery.

This is a multicenter, single-arm, open-label, phase 2 Window-of-opportunity trial to assess the activity of 1 cycle of preoperative retifanlimab plus platinum-etoposide chemo-immunotherapy regimen in patients with resectable MCC (stage IIA-III). Patients who meet the eligibility criteria will be treated with one cycle of chemo-immunotherapy. After receiving the short-course preoperative chemo-immunotherapy study regimen, patients will undergo standard radical surgery between weeks 5 and 6 from enrollment. After surgery, patients will receive adjuvant radiation therapy, if indicated, and afterwards, standard follow up will be started as per clinical practice and guidelines. Baseline radiological assessments will include chest/abdomen/pelvis CT scan with contrast and CT scan of additional anatomical sites should be performed if the primary tumor is elsewhere. The enrollment of patients will be temporary interrupted after the inclusion of first 6 patients in the trial. When 6 patients will complete the study treatment, a Safety Monitoring Committee will complete a safety evaluation. The enrollment will then resume only if the study treatment combination is judged feasible and no major safety concerns arise. The study primary endpoint will be the pathological complete response rate or pCR rate, defined as the percentage of patients, relative to the total of enrolled subjects in the intention-to-treat population, who will achieve a pathological complete response, as per central pathological review.