HPV-16 Vaccination and Pembrolizumab Plus Cisplatin for "Intermediate Risk" HPV-16-associated Head and Neck Squamous Cell Carcinoma

This study aims to enroll adult male and female patients who have intermediate risk disease with histologically-confirmed head and neck squamous cell carcinoma (HNSCC) with no evidence of distant metastasis. All patients will receive the same treatment and there is no active control group. In this trial, patients will undergo biopsy followed by treatment with the ISA101b vaccine which targets human papillomavirus (HPV). The vaccine treatment will begin 2 weeks prior to cisplatin and Intensity-Modulated Radiation Therapy (cisplatin-IMRT) and one week prior to the first dose of pembrolizumab, an anti-cancer immunotherapy targeting PD-1. The vaccine will be administered 2 additional times at weeks 2 and 5. Pembrolizumab will be initiated 1 week prior to cisplatin-IMRT at the dose of 200 mg IV q3 weeks (+/- 3 days). Pembrolizumab will be continued concurrently through cisplatin-IMRT (weeks 3, 6 ), and continued for a 15 week maintenance period after completion of cisplatin-IMRT for a total pembrolizumab treatment period of 24 weeks (8 doses; 6 months). The purpose of this study is to evaluate patient survival following this combination of treatments.