Until recently, palliative options for the treatment of platinum-refractory recurrent or metastatic head and neck squamous cell carcinoma (R/M HNSCC) have been cytotoxic chemotherapy and EGFR inhibitors. These agents offer limited efficacy with substantial toxicity. The development of novel immune checkpoint inhibitors has challenged the standard treatment. Pembrolizumab is a potent and highly selective humanized monoclonal antibody that blocks the interaction between PD-1, an immune checkpoint receptor and its ligands PD-L1 and -2. In August 2016, the US FDA approved the use of pembrolizumab in R/M HNSCC following disease progression on or after platinum-containing chemotherapy. This review highlights the pharmacology, therapeutic efficacy and tolerability data relevant to the use of pembrolizumab for the treatment of R/M HNSCC. Readers will gain greater insight into the HNSCC tumor microenvironment, available biomarkers, and learn about important clinical considerations associated with the use of pembrolizumab and similar immune checkpoint inhibitors.
Keywords: biomarkers; head and neck; immunotherapy.