Clinical and endoscopic features of checkpoint inhibitor-induced colitis and their association with selective immunosuppressive therapy use.

BACKGROUND AND AIMS: Immune checkpoint-inhibitor (ICI) colitis is a common adverse event that is primarily treated with corticosteroids but may require selective immunosuppressive therapy (SIT). Although endoscopic features have been associated with SIT use, it remains unclear whether these associations differ by ICI type. METHODS: We conducted a 2-center retrospective cohort study and included patients with histologically confirmed ICI colitis. Endoscopic images were reviewed by gastroenterologists specialized in inflammatory bowel disease (IBD) and scored using the Mayo score and the Immune-Mediated Colitis Endoscopic Score (IMCES). Early SIT use was defined as SIT use within 3 weeks after the start of colitis treatment. Features associated with SIT use were stratified by ICI type, and discriminative performance was evaluated using receiver operating characteristic (ROC) analysis. RESULTS: Among 255 included patients, 38% required SIT. Biochemical parameters associated with early SIT use were C-reactive protein (CRP) (odds ratio (OR), 1.41; P = .005), and albumin (OR, 0.92; P = .020). Endoscopic features associated with SIT use included erythema (OR, 4.09; P = .006) and exudate (OR, 3.24; P = .012), which were limited to patients treated with anti-cytotoxic T-lymphocyte-associated antigen 4-based (aCTLA-4-based) therapy. In multivariable analysis, ICI type remained the only variable associated with early SIT use (OR, 12.8; P < .001). The IMCES demonstrated areas under the curves (AUCs) of 0.57 (95% CI, 0.50-0.65) for overall and 0.61 (95% CI, 0.53-0.69) for early SIT use. CONCLUSIONS: In patients with ICI colitis, escalation to SIT use was primarily associated with ICI type, with limited additional value of biochemical or endoscopic features. The IMCES showed poor predictive performance in this external validation cohort.