Boosting Response: The Impact of Immune Checkpoint Inhibitors on Radiation Treatment Schedules

Abstract

The recent FDA approvals of immunomodulatory drugs such as Nivoluvamab (Opdivo),
Pembrolizumab (Keytruda) and Ipilimumab (Yervoy) for treatment of Non-small cell
lung cancer (NSCLC) and melanoma have renewed interest in cancer immunotherapy. Initial
attempts to activate the immune system to improve anti-tumor immunity by vaccination and/
or cytokine treatments failed due to low response rates and high toxicity.1,2 However, improved
knowledge of interactions between tumor cells and the immune system has led to a change in
strategy. Recently, it has been shown that tumors activate immune checkpoint pathways which
suppress any anti-tumor immune responses.3 Immune checkpoint inhibitors block these pathways
and can evoke the power of cytotoxic CD8+ T lymphocytes to eliminate cancer cells.