Impact of p16 Status and Anatomical Site in Anti-PD-1 Immunotherapy-Treated Recurrent/Metastatic Head and Neck Squamous Cell Carcinoma Patients

SIMPLE SUMMARY: Anti-PD-1 immunotherapies are approved for head and neck squamous cell carcinoma in the recurrent/metastatic setting, and utilization of these high-cost biologics is expected to increase as other indications are approved. Due to the high cost and selective response rate of these immunotherapy biologics in HNSCC, it is imperative to better define which patient subsets will realize a clinically meaningful benefit with anti-PD-1 treatment. The impact of anatomical site and p16 status on the efficacy of anti-PD-1 inhibitors remains unresolved. We showed that anatomical site and p16 status are associated with overall survival in anti-PD-1-treated HNSCC patients from a single-institution, real-world cohort. ABSTRACT: In head and neck squamous cell carcinoma (HNSCC), anti-PD-1 inhibitors are approved for recurrent/metastatic (R/M) disease and anticipated to expand to other indications. The impact of p16 status and anatomical site on overall survival (OS) in immunotherapy-treated HNSCC patients remains unresolved. We performed a retrospective analysis of R/M HNSCC patients receiving anti-PD-1 immunotherapy at our academic medical center with an extensive community satellite network. Fifty-three R/M HNSCC patients were treated with anti-PD-1 immunotherapy and had a median OS of 6 months. Anatomical site was associated with distinct OS; oropharynx and larynx patients have superior OS compared to oral cavity patients. Analysis of the OPSCC subset showed p16+ status as a favorable, independent prognostic biomarker (HR 7.67 (1.23–47.8); p = 0.029). Further studies to assess the link between anatomical site, p16 status, and anti-PD-1 treatment outcomes in large cohorts of R/M HNSCC patients managed in real-world clinical practices and clinical trials should be prioritized.