# Immune-related diarrhoea and colitis from checkpoint inhibitors, by grade

Source: https://onco.cc/protocols/irae-colitis/  
OnCo record `irae-colitis` (Protocol). Data CC BY-NC 4.0, attribute "Data from OnCo (onco.cc)"; commercial use needs a licence.

## TL;DR

Immunotherapy drugs such as pembrolizumab, nivolumab and ipilimumab can make the immune system attack the bowel, causing diarrhoea, tummy pain or blood in the stool. Ring your cancer team's 24-hour line as soon as diarrhoea starts. Mild cases are watched; anything more is treated with steroids, and if steroids do not work within a few days, with a drip such as infliximab.

## Summary

Diarrhoea is reported in about 44% of patients on combined CTLA-4 and PD-(L)1 blockade (10% grade 3 or more), 36% on CTLA-4 inhibitors and 11% on PD-(L)1 inhibitors; colitis in 16%, 8% and 1% respectively (SITC 2021). Median onset is 5 to 10 weeks.

SITC 2021: work up grade 1 with full blood count, metabolic panel and faecal lactoferrin, and continue the checkpoint inhibitor with monitoring. From grade 2, add faecal calprotectin and stool infection tests (C. difficile, CMV), hold the drug and start prednisone 1 mg/kg/day; grades 3 and 4 take 1 to 2 mg/kg/day, grade 4 intravenously. Sigmoidoscopy or colonoscopy with biopsy for grade 3 or more, or grade 2 lasting 5 days or more; CT for suspected perforation or toxic megacolon. Steroids are tapered within 4 weeks once symptoms reach grade 1 or less. No response in 3 to 5 days, recurrence on taper or severe ulceration at endoscopy: infliximab 5 mg/kg at 0, 2 and 6 weeks, switching to vedolizumab 300 mg on the same schedule if symptoms persist after the second infliximab dose. Screen for hepatitis B, HIV and tuberculosis first without delaying the dose. Re-challenge once symptoms are grade 1 or less on under 10 mg prednisone a day, after repeat endoscopy.

ASCO 2021 sets the general frame (continue for grade 1, hold for grade 2, high-dose steroids for grade 3, permanently stop for most grade 4) and tapers over at least 4 to 6 weeks, longer than SITC's 4 weeks for colitis. ESMO 2022 could not be read.

## Fields

- Kind: Protocol
- Last checked: 2026-11-11
- Also known as: checkpoint inhibitor colitis; immune checkpoint inhibitor diarrhoea; immune-mediated colitis; ICI colitis management; immunotherapy colitis
- Tags: protocol; irae; acute-oncology

## Connected records

- ideas: [Treat immunotherapy side-effects without wiping out the response](https://onco.cc/ideas/idea-bio2-steroid-sparing-irae/)
- technologies: [Immune checkpoint inhibitors](https://onco.cc/technologies/checkpoint-inhibitor/)
- drugs: [Atezolizumab](https://onco.cc/drugs/atezolizumab/), [Avelumab](https://onco.cc/drugs/avelumab/), [Cemiplimab](https://onco.cc/drugs/cemiplimab/), [Dostarlimab](https://onco.cc/drugs/dostarlimab/), [Durvalumab](https://onco.cc/drugs/durvalumab/), [Ipilimumab](https://onco.cc/drugs/ipilimumab/), [Nivolumab](https://onco.cc/drugs/nivolumab/), [Pembrolizumab](https://onco.cc/drugs/pembrolizumab/), [Prednisone](https://onco.cc/drugs/prednisone/), [Tremelimumab](https://onco.cc/drugs/tremelimumab/)
- institutions: [American Society of Clinical Oncology (ASCO)](https://onco.cc/institutions/asco/), [European Society for Medical Oncology (ESMO)](https://onco.cc/institutions/esmo/), [Society for Immunotherapy of Cancer](https://onco.cc/institutions/sitc/)
- terms: [Immune-mediated colitis and diarrhoea](https://onco.cc/terms/immune-colitis/), [Immune-related adverse events (irAEs)](https://onco.cc/terms/irae/)
- key papers: [ASCO 2021 guideline: how to recognise and manage the immune-related side effects of checkpoint inhibitors](https://onco.cc/key-papers/paper-asco-irae-guideline-jco-2021/)
- protocols: [Baseline tests and monitoring before and during checkpoint inhibitor treatment](https://onco.cc/protocols/checkpoint-inhibitor-baseline-and-monitoring/), [Checkpoint inhibitor hypophysitis and adrenal insufficiency: emergency treatment, replacement and steroid emergency card](https://onco.cc/protocols/irae-hypophysitis-adrenal/), [Immune-mediated hepatitis from checkpoint inhibitors, by grade](https://onco.cc/protocols/irae-hepatitis/), [Immune-related pneumonitis from checkpoint inhibitors, by grade](https://onco.cc/protocols/irae-pneumonitis/), [Immune-related skin reactions from checkpoint inhibitors, including blistering and severe erosive rashes](https://onco.cc/protocols/irae-skin/), [Restarting a checkpoint inhibitor after an immune-related side effect](https://onco.cc/protocols/irae-rechallenge/), [Steroid taper after immunotherapy side effects, with Pneumocystis prophylaxis and adrenal checks](https://onco.cc/protocols/irae-steroid-taper-and-pjp/)

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