Immune-Related Adverse Events and Immune Checkpoint Inhibitor Efficacy in Patients with Gastrointestinal Cancer with Food and Drug Administration-Approved Indications for Immunotherapy.

Predictive clinical biomarkers for immune checkpoint inhibitor response have been understudied in the field of immuno-oncology. Immune-related adverse event onset appears to be one such biomarker. Across tumor types, immune-related adverse event onset has been associated with response to anti-programmed cell death protein 1 (PD-1) antibodies. The results of this study demonstrate this for the first time in patients with gastrointestinal cancer receiving anti-PD-1 antibodies. Before immune-related adverse event onset can be adopted clinically as a predictive biomarker for immune checkpoint inhibitor response, however, larger prospective studies are needed to better understand the nuances between immune-related adverse event characteristics (severity, site, management, timing of onset) and immune checkpoint inhibitor effectiveness.