Pembrolizumab for the treatment of thoracic malignancies: current landscape and future directions.

New insights into the interaction between the immune system and the tumor microenvironment have led to the development of checkpoint inhibitors that target the PD-1/PD-L1 pathway. Pembrolizumab (MK-3475, lambrolizumab, Keytruda(®)) is a PD-1 inhibitor that has shown clinical activity in a variety of solid tumors and is currently approved for the second-line treatment of PD-L1-positive non-small-cell lung cancer and for unresectable/metastatic melanoma. This article will discuss the results of early-phase trials of pembrolizumab in thoracic malignancies as well as ongoing studies aimed to confirm clinical benefit.