Diagnosis and Management of Immune Checkpoint Inhibitor Colitis

Abstract

Increased use of immune checkpoint inhibitors (ICIs) has created a rise in immune-related adverse events (irAEs), which may affect any system in the body. Gastrointestinal (GI) irAEs such as immune-mediated colitis are common, occurring in 35% to 50% of patients receiving ICIs. GI irAEs usually develop 6 to 8 weeks after ICI initiation and can involve any part of the GI system. Patients with immune-mediated colitis are categorized into 1 of 5 grades based on the National Cancer Institute's Common Terminology Criteria for Adverse Events, which also guide treatment decisions. An infectious cause for the diarrhea should be excluded in all patients. Patients with grade 1 symptoms are managed conservatively. Patients with grade 2 or higher symptoms should undergo a colonoscopy and are treated with systemic corticosteroids and, depending on their response, biologic therapy. The aim of this article is to review the diagnosis and management of patients with immune-mediated colitis, which should be identified early and addressed promptly to avoid detrimental outcomes.

Keywords: Immune checkpoint inhibitors; biologic therapy; colitis; diarrhea; immune-related adverse events.

Figure 1.

Endoscopic appearance of immune-mediated colitis.

Figure 2.

Management algorithm for patients with immune-mediated colitis. Adapted from Collins et al and Powell et al. ASCO, American Society of Clinical Oncology; CTLA-4, cytotoxic T-lymphocyte–associated antigen 4; ICI, immune checkpoint inhibitor; NCCN, National Comprehensive Cancer Network. ^aWhen biologic therapy is initiated, either infliximab or vedolizumab can be administered. Infliximab is given at a dose of 5 mg/kg at weeks 0, 2, and 6, whereas vedolizumab is given at a dose of 300 mg at weeks 0, 2, and 6.