Pembrolizumab for the treatment of PD-L1 positive advanced or metastatic non-small cell lung cancer.

The emergence of immune checkpoint inhibitors marked an important advancement in the development of cancer therapeutics. Pembrolizumab is a selective humanized IgG4 kappa monoclonal antibody that inhibits the programmed death-1 (PD-1) receptor, an integral component of immune checkpoint regulation in the tumor microenvironment. The drug is currently approved by the Food and Drug Administration for the treatment of advanced melanoma and metastatic squamous and nonsquamous non-small cell lung cancer (NSCLC). Several published studies demonstrate that single-agent pembrolizumab is safe and has efficacy in patients with NSCLC. Many ongoing protocols are investigating the role of pembrolizumab in combination with other agents in lung cancer and various other cancer types. We review the available data on pembrolizumab in NSCLC and examine the role of potential predictive biomarkers of response to therapy.