A Study of INCMGA00012 in Metastatic Merkel Cell Carcinoma

Inclusion Criteria:

- Signed informed consent.

- Diagnosis of MCC with distant metastatic disease as a component of tumor burden and no
more than 3 prior systemic treatments, inclusive of systemic adjuvant therapy.

- 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 programmed cell death protein 1 (PD-1) or programmed cell death ligand protein 1
(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 in 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 autoimmune disorders.

- Active bacterial, fungal, or viral infections, including hepatitis A, B, and C.

- Receipt of a live vaccine within 90 days of planned start of study therapy.

- Current use of protocol-defined prohibited medication.

- Known hypersensitivity to another monoclonal antibody that cannot be controlled with
standard measures (eg, antihistamines and corticosteroids).

- Inability or unlikely, in the opinion of the investigator, to comply with the Protocol
requirements.

- Participant who is pregnant or breastfeeding.