Immune checkpoint inhibitors: making immunotherapy a reality for the treatment of lung cancer.

Despite the limited success of immunotherapies in solid malignancy, two human cancers, melanoma and renal cancer, have, for many years, responded to systemic administration of immune-targeted biologics and showed signals of response to certain therapeutic vaccines. These findings underpinned a long-held perception that melanoma and renal cancer were uniquely "immunogenic" but that virtually all other human cancers were not and thus would not respond to immune modulation. That notion has now been shattered by the significant and durable responses in non-small cell lung cancer induced by therapeutic treatment with antibodies blocking the PD-1 checkpoint. The immunotherapy success in lung cancer thus provides a gateway to development of treatments for multiple cancer types that were previously believed not accessible to immune-based therapies. ©2013 AACR.