Neoadjuvant Immunoradiotherapy With Evorpacept and Pembrolizumab in HPVOPC (Human Papilloma Virus Oropharynx Cancer)

After stereotactic radiation to primary tumor and neck on week 1 of study, Evorpacept 45 mg/kg is administered by IV infusion every three weeks starting on Week 2, Day 1 of study for a total two 21-day cycles (6 weeks)