Checkpoint inhibitors and gastrointestinal immune-related adverse events

Recent development of checkpoint inhibitors is a challenge for oncologists. Indeed, it leads to specific immune adverse events, close to autoimmune disorders, which require a specific management. Colitis is one of the most frequent immune adverse events, in particular with anticytotoxic T-lymphocyte-associated antigen 4 (CTLA-4) therapy.

Severe colitis is frequent with immune checkpoint inhibitors and leads in a few cases to bowel perforation and death. This review focuses on specific pathogenic pathway and recent findings on risk factors and managements of colitis.

Anti-CTLA-4 antibodies are the most involved immune checkpoint inhibitors in colitis, and the combinations with anti-programmed death ligand 1 dramatically increase the rate of colitis. The early use of budesonide, and in some cases corticosteroids and/or infliximab should be recommended, as colitis is responsive to infliximab in almost all cases. Immune-related colitis shares some characteristics with inflammatory bowel disease but with little specificity. In particular, it has been recently showed that gut microbiota could interact with anti-CTLA-4 treatment to modulate efficacy but also to induce colitis. This opens the way for preventive or curative treatments capable of inducing modulation of the microbiota or fecal transplantation.