Gastrointestinal toxicity of immune checkpoint inhibitors: from mechanisms to management

Immune checkpoint inhibitors promote an antitumour immune response by blocking signalling via either the cytotoxic T lymphocyte antigen 4 (CTLA4) pathway or the programmed cell death protein 1 (PD1) pathwayTheir use can result in immune-related adverse events, including the development of gastrointestinal inflammation, which shares certain clinicopathological features with IBDIn suspected cases of persistent mild or moderate-to-severe immune checkpoint inhibitor-induced gastrointestinal inflammation, endoscopic and histological investigation should be arranged to confirm the diagnosis, and other possible causes of symptoms should be excludedCorticosteroids should be used in the first instance to manage inflammation, and in patients who are refractory to corticosteroids, the addition of infliximab or vedolizumab should be considered