Pembrolizumab, a newer drug, harnesses T cells to tackle cancer. For certain lung cancer patients, this means having twice the lifespan than that accorded by chemotherapy!
For patients battling lung cancer, the majority are of the non-small-cell lung carcinoma (NSCLC) subtype. Among these, a subgroup of tumors produce a protein, PD-L1, which enables escape from attack by the patient’s immune system (see here). Specifically, PD-L1 binds to PD-1 receptors on T cells, thereby preventing T cells from activating, proliferating, and/or producing cytokines, so that T cells do not mount an attack towards the PD-L1-positive tumor cells.