Current Landscape of Immunotherapy for the Treatment of Metastatic Non-Small-Cell Lung Cancer

For patients with advanced non-small-cell lung cancer (NSCLC) lacking a targetable molecular driver, the mainstay of treatment has been cytotoxic chemotherapy. The survival benefit of chemotherapy in this setting is modest and comes with the potential for significant toxicity. The introduction of immunotherapeutic agents targeting the programmed cell death 1 protein (PD-1) and the programmed cell death ligand 1 (PD-L1) has drastically changed the treatment paradigms for these patients. Three agents—atezolizumab, nivolumab, and pembrolizumab—have been shown to be superior to chemotherapy in the second-line setting. For patients with tumours strongly expressing PD-L1, pembrolizumab has been associated with improved outcomes in the first-line setting. Demonstration of the significant benefits of immunotherapy in NSCLC has focused attention on new questions. Combination checkpoint regimens, with acceptable toxicity and potentially enhanced efficacy, have been developed, as have combinations of immunotherapy with chemotherapy. In this review, we focus on the published trials that have changed the treatment landscape in advanced NSCLC and on the ongoing clinical trials that offer hope to further improve outcomes for patients with advanced NSCLC.