Published online Feb 26, 2019. doi: 10.12998/wjcc.v7.i4.405
Peer-review started: September 21, 2018
First decision: October 16, 2018
Revised: January 21, 2019
Accepted: January 26, 2019
Article in press: January 26, 2019
Published online: February 26, 2019
Processing time: 158 Days and 7.9 Hours
Immune checkpoint inhibitors (ICIs) are monoclonal antibodies that target down-regulators of the anti-cancer immune response: Cytotoxic T-lymphocyte antigen-4, programmed cell death protein-1, and its ligand programmed death-ligand 1. ICIs have revolutionized the treatment of a variety of malignancies. However, many immune-related adverse events have also been described which mainly occurs as the immune system becomes less suppressed, affecting various organs including the gastrointestinal tract and causing diarrhea and colitis. The incidence of immune-mediated colitis (IMC) ranges from 1%-25% depending on the type of ICI and if used in combination. Endoscopically and histologically there is a significant overlap between IMC and inflammatory bowel disease, however more neutrophilic inflammation without chronic inflammation is usually present in IMC. Corticosteroids are recommended for grade 2 or more severe colitis while holding the immunotherapy. About one third to two thirds of patients are steroid refractory and benefit from infliximab. Recently vedolizumab has been found to be efficacious in steroid and infliximab refractory cases. While in grade 4 colitis, the immunotherapy is permanently discontinued, the decision is controversial in grade 3 colitis.
Core tip: Immune-mediated colitis (IMC) is a common immune related adverse event associated with immune checkpoint inhibitors. It typically occurs 5 wk-10 wk after the 2nd or 3rd dose of treatment. Endoscopically, it is indistinguishable from inflammatory bowel disease with significant overlap in histology. Optimal management of IMC requires early recognition and timely use of corticosteroids. About one third to two thirds of patients are steroid refractory. Infliximab is the second line therapy in these patients. Recent reports have shown that Vedolizumab is more gut specific and efficacious in steroid and infliximab refractory cases. Fecal microbiota transplant has recently been reported to be successful in steroid refractory cases.