Immune Checkpoint Inhibitors in the Treatment of Cancer

Background: Immunotherapy drugs, known as immune checkpoint inhibitors (ICIs), work by blocking checkpoint proteins from binding with their partner proteins. The two main pathways that are specifically targeted in clinical practice are cytotoxic T-lymphocyte antigen-4 (CTLA- 4) and programmed cell death protein 1 (PD-1) that showed potent immune-modulatory effects through their function as negative regulators of T cell activation. Methods: In view of the rapid and extensive development of this research field, we conducted a comprehensive review of the literature and updated on the use of CTLA-4, PD-1, and PD-L1 targeted therapy in the treatment of several types of cancer, including melanoma, non-small-cell lung carcinoma, breast cancer, hepatocellular carcinoma, Hodgkin lymphoma, cervical cancer, and head and neck squamous cell carcinoma. Results: Based on the last updated list released on March 2019, seven ICIs are approved by the FDA, including ipilimumab, pembrolizumab, nivolumab, atezolizumab, avelumab, durvalumab, and cemiplimab. Conclusion: This review highlighted the most common adverse effects caused by ICIs which affect people in different ways.