PROSTVAC in Combination With Nivolumab in Men With Prostate Cancer

PROSTVAC-V (vaccinia) will be administered subcutaneously in an extremity (e.g., thigh) at a dose of 2x10\^8 infectious units. PROSTVAC-F (fowlpox) will be administered subcutaneously in an extremity (e.g., thigh) at a dose of 1x10\^9 infectious units.

Nivolumab is to be administered as a flat dose over approximately 30-minutes via intravenous (IV) infusion.

Participants in the neoadjuvant cohort will undergo a radical prostatectomy in week 9. (If surgery is scheduled earlier than 9 weeks after initial dosing, the 6 and 8 week dosing may be skipped, and surgery may be done as early as week 5.)

A baseline biopsy is performed for participants in the neoadjuvant cohort that do not have a previous collection of biopsy material.

Participants who experience aches or fever after vaccination may take Tylenol as directed.