Patients with inflammatory bowel disease can safely receive immune checkpoint inhibitors for cancer, most of whom continue treatment despite a nearly five-fold increased risk of immune-mediated colitis, research has found.

The results challenge the routine exclusion of patients with autoimmune diseases including ulcerative colitis, Crohn’s disease and microscopic colitis from immunotherapy trials due to concerns about exacerbating their underlying condition, the researchers say.

The Danish nationwide cohort included 85 patients with those conditions who received checkpoint inhibitors between 2010 and 2024, comparing them with 81 melanoma patients without intestinal disease.

Immune-mediated enterocolitis developed in 46% of IBD patients compared with 16% of controls. Patients with intestinal inflammatory diseases had a significantly higher risk when treated with anti-PD-1/anti-PD-L1 inhibitors (hazard ratio 4.93, P<0.001).

However, multivariate analysis revealed patients with Crohn’s disease had substantially lower odds of developing enterocolitis compared with UC and microscopic colitis patients (OR 0.07, P=0.02).

“Treatment with ICI in patients with UC, CD, and MC is overall well tolerated and should be considered on the basis of the same criteria as in patients without intestinal diseases,” the authors concluded in JCO Oncology Practice [link here].

Of 39 patients who developed immune-mediated colitis, 23 required hospitalisation with a median stay of five days. Six patients received rescue biologic treatment with infliximab or vedolizumab as first-line therapy.

Two patients required colectomy, but notably, none of the deaths recorded during follow-up were directly attributable to immune-mediated enterocolitis.

The study had several limitations. Its retrospective design meant many patients did not undergo endoscopy during colitis episodes. Treatment selection bias was likely, as oncologists may have avoided offering checkpoint inhibitors to patients with severe active IBD.

Beyond that, the high proportion of patients without immunosuppressive medication at checkpoint inhibitor initiation suggested oncologists exercised caution in patient selection, potentially limiting generalisability, they said.

“Although the risk of IMC in patients with UC, CD, or MC is elevated, ICIs remain an essential therapy for malignancies such as melanoma, renal cancer, and lung cancer, given their demonstrated survival benefits,” the authors concluded.