Biomarkers of immune checkpoint inhibitor response and toxicity: Challenges and opportunities

Immune checkpoint inhibitors have transformed cancer therapy, but their optimal use is still constrained by lack of response and toxicity. Biomarkers of response may facilitate drug development by allowing appropriate therapy selection and focusing clinical trial enrollment. However, aside from PD-L1 staining in a subset of tumors and rarely mismatch repair deficiency, no biomarkers are routinely used in the clinic. In addition, severe toxicities may cause severe morbidity, therapy discontinuation, and even death. Here, we review the state of the field with a focus on our research in therapeutic biomarkers and toxicities from immune checkpoint inhibitors.

Automated summary

Immune checkpoint inhibitors have revolutionized cancer therapy, but their full potential is still limited by issues such as lack of response and toxicities. Biomarkers of response can aid in drug development by guiding appropriate therapy selection and clinical trial enrollment. However, apart from PD-L1 staining and mismatch repair deficiency, there are currently no routinely used biomarkers in clinical practice. Severe toxicities can also have detrimental effects on patient outcomes. In this review, we provide an overview of therapeutic biomarkers and toxicities associated with immune checkpoint inhibitors.