Impact of concurrent CMV-positive colitis on clinical outcomes in immune checkpoint inhibitor-induced colitis
File(s)
Published version
Author(s)
Type
Journal Article
Abstract
Background and aims
Immune checkpoint inhibitors (ICI) frequently trigger ICI-colitis, commonly leading to ICI discontinuation. With expanding ICI use, ICI-colitis is emerging as a significant clinical challenge. Cytomegalovirus (CMV) infection is known to occur in ICI-colitis, but its prevalence, risk factors and clinical impact are poorly defined. This study aimed to characterise the clinical trajectory of ICI-colitis patients with concurrent colonic CMV infection as compared to a CMV-negative colitis group.
Methods
We retrospectively analysed consecutive ICI-treated patients with endoscopically and/or histologically confirmed ICI-colitis at two UK hospitals between 2015 and 2024. Clinical, endoscopic (Mayo Endoscopic Score, MES), treatment and oncologic outcome data were collected. CMV was identified by immunohistochemistry (IHC) on colonic biopsies. CMV-positive colitis cases were compared with CMV-negative colitis using chi- squared, Mann–Whitney U, and multivariable regression analyses.
Results
Among 249 ICI-colitis patients, IHC proven CMV-positive colitis was detected in 21 (8.4%). CMV-positive colitis was associated with dual ICI therapy (OR 2.8, CI 1.06–7.15), prior infliximab exposure (OR 6.4, CI 2.56–16.7), bloody stool (OR 2.7, CI 1.05–6.69), and higher endoscopic severity (MES 2–3; OR 4.1, CI 1.60–10.38), despite similar CTCAE diarrhoea grades between groups. They also had a higher likelihood of requiring escalation to advanced therapy (80% vs 41.5%; OR 5.6, CI 1.96–15.74), with this association remaining significant after adjusting for endoscopic severity (p = 0.049).
Colectomy rates were higher albeit low overall. Antiviral therapy did not significantly affect corticosteroid duration or recurrence, and CMV tissue status did not influence overall or progression-free survival.
Conclusion
Concurrent CMV-positive colitis occurs in a notable subset of ICI-colitis patients and may worsen disease severity, highlighting the importance of endoscopic biopsy, especially in steroid-refractory cases.
Immune checkpoint inhibitors (ICI) frequently trigger ICI-colitis, commonly leading to ICI discontinuation. With expanding ICI use, ICI-colitis is emerging as a significant clinical challenge. Cytomegalovirus (CMV) infection is known to occur in ICI-colitis, but its prevalence, risk factors and clinical impact are poorly defined. This study aimed to characterise the clinical trajectory of ICI-colitis patients with concurrent colonic CMV infection as compared to a CMV-negative colitis group.
Methods
We retrospectively analysed consecutive ICI-treated patients with endoscopically and/or histologically confirmed ICI-colitis at two UK hospitals between 2015 and 2024. Clinical, endoscopic (Mayo Endoscopic Score, MES), treatment and oncologic outcome data were collected. CMV was identified by immunohistochemistry (IHC) on colonic biopsies. CMV-positive colitis cases were compared with CMV-negative colitis using chi- squared, Mann–Whitney U, and multivariable regression analyses.
Results
Among 249 ICI-colitis patients, IHC proven CMV-positive colitis was detected in 21 (8.4%). CMV-positive colitis was associated with dual ICI therapy (OR 2.8, CI 1.06–7.15), prior infliximab exposure (OR 6.4, CI 2.56–16.7), bloody stool (OR 2.7, CI 1.05–6.69), and higher endoscopic severity (MES 2–3; OR 4.1, CI 1.60–10.38), despite similar CTCAE diarrhoea grades between groups. They also had a higher likelihood of requiring escalation to advanced therapy (80% vs 41.5%; OR 5.6, CI 1.96–15.74), with this association remaining significant after adjusting for endoscopic severity (p = 0.049).
Colectomy rates were higher albeit low overall. Antiviral therapy did not significantly affect corticosteroid duration or recurrence, and CMV tissue status did not influence overall or progression-free survival.
Conclusion
Concurrent CMV-positive colitis occurs in a notable subset of ICI-colitis patients and may worsen disease severity, highlighting the importance of endoscopic biopsy, especially in steroid-refractory cases.
Date Issued
2026-07-26
Date Acceptance
2026-05-05
Citation
European Journal of Cancer, 2026, 243
ISSN
0959-8049
Publisher
Elsevier
Journal / Book Title
European Journal of Cancer
Volume
243
Copyright Statement
© 2026 The Authors. Published by Elsevier Ltd. This is an open access article under the CC BY license (http://creativecommons.org/licenses/by/4.0/).
License URL
Publication Status
Published
Article Number
116795
Date Publish Online
2026-05-22