Research in context
Evidence before this study
To identify other published studies of the programmed death 1 (PD-1) receptor or PD-L1 inhibitors in squamous cell carcinoma of the head and neck, we searched the PubMed database using the following search terms, not limited by date or language restrictions: “PD-1 OR PD-L1 OR MK-3475 OR lambrolizumab OR nivolumab OR BMS-936558 OR MPDL3280A OR BMS-936559 AND HNSCC.” Although preclinical evidence strongly supports the use of PD-1 blockade to enhance antitumour activity in squamous cell carcinoma of the head and neck (eg, Malm and colleagues, 2015), this search did not identify any other clinical studies assessing PD-1 or PD-L1 inhibitors in patients with squamous cell carcinoma of the head and neck.
Added value of this study
To our knowledge, this is the first report of the efficacy and safety of a PD-1 or PD-L1 inhibitor in patients with PD-L1-positive recurrent or metastatic squamous cell carcinoma of the head and neck. Pembrolizumab was well tolerated and showed clinically significant antitumour activity in this heavily pretreated population. Results of this study also show that pembrolizumab efficacy was associated with PD-L1 and interferon-γ-related gene expression, supporting further assessment of predictive biomarkers for pembrolizumab in future studies.
Implications of all the available evidence
The high proportions of patients achieving an overall response to PD-1 blockade and durability of responses and stable disease observed with pembrolizumab support the importance of the PD-1 pathway in squamous cell carcinoma of the head and neck, and warrants further study of pembrolizumab as an anticancer treatment for advanced head and neck cancers.