Predictive and Prognostic Value of p16 in Head and Neck Squamous Cell Carcinoma Patients Treated with Molecular Targeted Agents or Immune Checkpoint Inhibitors: Subgroup Analysis of the TRIUMPH Study

Objective The aim of this study is to assess the predictive and prognostic value of p16 in recurrent/metastatic HNSCC patients treated with molecular targeted agents (MTAs) or immune checkpoint inhibitors (ICIs).Study design The TRIUMPH trial (NCT03292250) was a multi-arm phase II umbrella trial using next-generation sequencing for patients with HNSCC. Patients were assigned to specific treatment arms including PIK3CA, EGFR/HER2, FGFR, CDK4/6 inhibitors, and ICI based on their genomic profiles. We performed post hoc analysis using 86 patients who had available p16 immunohistochemistry results. ORR, PFS, and OS were analyzed by p16 positivity.Results The p16 positivity rate was 33.7%. ORR was 20.7% for p16 (+) compared to 8.8% for p16 (–) patients (P = 0.072). Median PFS was 3.8 months for p16 (+) and 1.8 months for p16 (–) (P = 0.030). Median OS was 12.9 months for p16 (+) and 6.2 months for p16 (–) (P = 0.100).Conclusion Patients with p16 (+) showed longer PFS and OS compared to p16 (–) patients. This suggests that p16 has prognostic and predictive values in HNSCC patients who are treated with MTAs or ICIs.