Pembrolizumab in the first-line treatment of advanced head and neck cancer

Recurrent or metastatic (R/M) head and neck squamous cell carcinoma (HNSCC) is associated with dismal prognosis and has limited therapeutic options. PD-1/PD-L1 axis blockade was initially shown to improve outcomes in platinum-refractory HNSCC. More recently, pembrolizumab monotherapy or pembrolizumab combined with chemotherapy resulted in better overall survival than platinum, 5-fluorouracil, and cetuximab (EXTREME regimen) as first-line therapy for R/M HNSCC, establishing a new standard-of-care therapy for this disease. We review pembrolizumab in the first-line treatment of R/M HNSCC and summarize the impact of PD-L1 expression, tumor and symptom burden, and patient’s performance status on treatment decisions. Future perspectives are summarized. The standard-of-care first-line therapy for R/M HNSCC is pembrolizumab monotherapy for patients with a PD-L1 combined positive score (CPS)≥1 or pembrolizumab combined with platinum and 5-fluorouracil for patients with any PD-L1 status. Addition of chemotherapy to pembrolizumab increases the response rate but also toxicity and is preferred for patients with good performance status and significant tumor and symptom burden. For patients with a PD-L1 CPS <1, the EXTREME regimen should be considered. New strategies combining pembrolizumab with targeted therapies and immune checkpoints inhibitors are being explored to synergize or overcome resistance to anti-PD-1.