A Study of INCMGA00012 in Metastatic Merkel Cell Carcinoma (POD1UM-201)

Inclusion Criteria: * Signed informed consent. * Diagnosis of MCC with distant metastatic disease or recurrent, advanced locoregional disease not amenable to surgery or radiation * Eastern Cooperative Oncology Group performance status of 0 to 1. * Measurable disease according to RECIST v1.1. * Availability of tumor tissue (fresh or archival) for central pathology review. * Willingness to avoid pregnancy or fathering children based on protocol-defined criteria. Exclusion Criteria: * Prior systemic therapy for MCC, including chemotherapy and prior PD-1 or PD-L1-directed therapy. * Treatment with anticancer drugs or participation in another interventional clinical study within 21 days before the first administration of study drug. * Has not recovered to ≤ Grade 1 or baseline from toxic effects of prior therapy (with the exceptions for anemia not requiring transfusion support and any grade of alopecia) and/or complications from prior surgical intervention within 7 days before starting study treatment. * Radiation therapy administered within 2 weeks of first dose of study treatment or radiation therapy to the thoracic region that is \> 30 Gy within 6 months of the first dose of study treatment. * Known central nervous system (CNS) metastases and/or carcinomatous meningitis. * History of second malignancy within 3 years (with exceptions). * Laboratory values outside the protocol-defined range at screening. * Clinically significant pulmonary, cardiac, gastrointestinal or autoimmu…