Objectives:~Primary Objective:~To assess whether adjuvant anti-PD1 will lead to the clearance of the virus in the oral rinse and/or plasma cfDNA in HPV+ OPC patients with persistent HPV following definitive therapy~Secondary Objectives:~One-year recurrence-free survival (1-yr RFS),~2-year RFS (2-yr RFS),~Overall survival (2-yr OS),~Safety and tolerability~Compliance~Quality of life (EORTC C30 will be utilized)~Correlative/Exploratory Objectives:~Time to viral clearance in the oral rinse and plasma cfDNA with anti-PD1 treatment~The concordance between plasma HPV and oral rinse HPV at diagnosis, post-definitive treatment and during adjuvant treatment~The correlation between tumor mutations and persistence of HPV in oral rinse/cfDNA.~The correlation between recurrence site (loco-regional vs. distant metastasis) and oral rinse vs.~plasma HPV detection
This study aims to leverage this unique property of HPV+ OPC to detect possible minimal residual disease represented by persistent viral detection after the completion of definitive treatment. The study will offer adjuvant immune therapy to patients with persistent viral detection and evaluate the clearance of viral load. It will evaluate the rate of viral clearance with immune therapy and establish the link between viral clearance and long-term disease control.