Study To Evaluate The Safety, Tolerability And Immunogenicity Of 4 mg Of ITI-3000 In Patients With Polyomavirus-Positive Merkel Cell Carcinoma (MCC)

This is a single dose design examining 4 mg dose of the DNA vaccine ITI-3000 in participants who were diagnosed with polyomavirus-positive MCC, histologically confirmed by an expert pathologist on standard clinical staining, that may have been supplemented by specific staining for Cytokeratin 20 (CK20) and/or other markers used to distinguish MCC.

Evidence of Merkel cell polyomavirus (MCPyV) in the tumor at initial presentation (pre-therapy) can be provided by a positive anti-MCPyV oncoprotein antibody AMERK Test.

Participants in the study are those who are both diagnosed and have completed standard of care (SOC) surgical and/or radiation therapy at least 1 year prior to enrollment in the study and have no evidence of active disease (NEAD). Participants those who were previously diagnosed with MCC, and had recurrence and also exhibited no evidence of active disease (NEAD) for more than 2 years prior to enrollment in the study.

NEAD is confirmed by physical examination, a negative AMERK test (\<74 STU) in participants with a prior positive AMERK test, or significantly decreased, stable AMERK titers in 2 or more consecutive draws compared to prior positive AMERK test at the time of diagnosis, in the setting of a negative computed tomography (CT) scan of the chest, abdomen and pelvis or PET-CT within 3 months of enrollment into the study.

Eight participants will be enrolled at 4 mg total DNA dose to assess safety, tolerability, and immunologic response to the ITI-3000 vaccine.