Mutational Landscape of Recurrent/Metastatic Head and Neck Squamous Cell Carcinoma and Association with Immune Checkpoint Inhibitor Outcomes.

Abstract

Understanding the mutational landscape of recurrent/metastatic head and neck squamous cell carcinoma (R/M HNSCC) is important in identifying biomarkers to determine which patients may benefit from immune checkpoint inhibitors (ICI). The HAWK (NCT02207530), CONDOR (NCT02319044), and EAGLE (NCT02369874) studies evaluated R/M HNSCC treatment with durvalumab or durvalumab-tremelimumab. Tumor tissue samples pooled from HAWK/CONDOR (n = 153) and plasma cell-free DNA samples from EAGLE (n = 285) were analyzed to identify somatic alterations and association with survival. The mutational landscape was similar in tissue and plasma. Compared with the wild type, TP53 mutations were associated with significantly shorter overall survival (OS; HR; 95% confidence interval) with standard of care (SoC; EAGLE: 2.12; 1.20-3.78) and ICIs (HAWK/CONDOR: 1.49; 1.05-2.12 and EAGLE: 1.44; 0.99-2.10). In EAGLE, patients with TP53 mutations had significantly longer OS with durvalumab-tremelimumab versus SoC (P = 0.045). KMT2D mutations were associated with a trend toward longer OS (HR; 95% confidence interval) versus the wild type in HAWK/CONDOR (0.81; 0.56-1.19) and a trend toward longer OS with ICIs versus SoC in EAGLE. For both mutations, a European Cooperative Oncology Group performance status of 1 was associated with worsened OS, and PD-L1 positivity was associated with improved OS. This is the first large-scale study to show the mutational landscape of R/M HNSCC and its association with clinical outcomes in patients treated with ICIs or SoC. The TP53 mutation was a negative prognostic marker; however, treatment with durvalumab-tremelimumab significantly improved survival over SoC. Further investigation of KMT2D as a predictive biomarker for immunotherapy in R/M HNSCC is warranted.