Abstract
Activation of the host immune system represents an attractive treatment approach for cancers. In non-small-cell lung cancer (NSCLC), a variety of immunotherapies, including nonspecific immune stimulants, vaccines and checkpoint inhibitors, have been evaluated in clinical trials. Several randomized Phase III trials have failed to demonstrate clinical benefit from nonspecific immune stimulants and vaccines in the overall trial populations. Activity of vaccines in subsets of patients in these trials needs further evaluation. Unlike vaccines aimed at stimulating a cellular immune response to antigens differentially expressed in cancers, checkpoint inhibitors aim at overcoming immune inhibitory signals in the tumor microenvironment via pharmacological inhibition of immune checkpoints – a crucial tumoral immune escape mechanism. Early clinical trials of checkpoint inhibitors showed promising results with some durable responses. Better understanding of the mechanisms of immunosuppression specific to NSCLC will be crucial for successful patient selection for immunotherapy.