Key points are not available for this paper at this time.
AbstractBackground and aims Immune checkpoint inhibitors (ICI) frequently trigger ICI-colitis, commonly leading to ICI discontinuation. With increasing ICI use, ICI-colitis is an emerging clinical challenge. Cytomegalovirus (CMV) infection is known to occur in ICI-colitis, but its prevalence, risk factors, and impact are poorly defined. This study aimed to characterise colonic CMV infection in ICI-colitis using robust definitions, and a CMV- negative colitis comparator 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), bloody stool (OR 2.7, CI 1.05-6.69) and higher endoscopic severity (MES 2–3; OR 4.1, CI 1.60 to 10.38), despite similar diarrhoea grades between groups. Prior infliximab exposure was strongly linked to CMV-positive colitis (OR 6.4, CI 2.56-16.7) and a higher likelihood of requiring escalation to advanced therapy (80% vs 41.5%; OR 5.6, CI 1.96-15.74), with the 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.
Ibraheim et al. (Fri,) studied this question.