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

Endoscopy retrospective · n=255 · Aug 21, 2026 · Inflamm Bowel Dis · IF 4.5

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

Diagnosticbiomarker

Clinical takeawayIn ICI colitis, escalation to immunosuppressive therapy is primarily determined by ICI type and clinical progression, not mucosal endoscopic appearance. Do not use IMCES (AUC 0.57) or endoscopic features (erythema, exudate) to predict escalation. Monitor for clinical worsening-progressive diarrhea especially bloody, fever, severe abdominal pain, or laboratory decline (rising CRP, falling albumin)-as signals for escalation need. ICI type carries dominant risk; ipilimumab and aCTLA-4-based therapies warrant particular vigilance. Base escalation decisions on symptom trajectory and known ICI immunobiology, not endoscopic severity scoring.

What it foundAmong 255 patients with histologically confirmed ICI colitis, 38% required selective immunosuppressive therapy escalation. ICI type was the dominant multivariable predictor (OR 12.8). Endoscopic features (erythema OR 4.09, exudate OR 3.24) and biochemical markers offered minimal additional predictive value. The Immune-Mediated Colitis Endoscopic Score (IMCES) demonstrated poor discriminative ability (AUC 0.57 overall, 0.61 for early escalation).

ContextCurrent practice often applies endoscopic severity scoring (Mayo, IMCES) to grade ICI colitis severity and inform escalation to immunosuppressive therapy. This external validation shows IMCES performs poorly (AUC 0.57, barely better than chance) and reveals that ICI type and drug immunology, rather than mucosal findings, determine escalation risk.

Reinforcessuggested applicable standard· American Gastroenterological Association (AGA), "AGA Clinical Practice Update on Diagnosis and Management of Immune Checkpoint Inhibitor Colitis and Hepatitis: Expert Review" (Dougan M, Wang Y, Rubio-Tapia A, Lim JK), Gastroenterology 2021;160(4):1384-1393

Decision at stakewhether endoscopic severity scoring helps identify ICI colitis patients who will need escalation to selective immunosuppressive therapy

… In grade 2 or higher colitis/diarrhea, early stool inflammatory markers (lactoferrin, calprotectin) may help stratify patients for endoscopy, and endoscopic confirmation of the diagnosis and severity should be considered before starting high-dose systemic glucocorticoids; abdominal imaging is reserved for dominant pain, fever, or bleeding and should not be done routinely for diarrhea alone. …

From our summary of this standard, unedited — the part the paper bears on. … marks omitted text. Our wording, not the guideline's; read the source for its own text.

Our full summary of this standard

For suspected ICI colitis, exclude infectious causes of diarrhea (including C. difficile) before treating. In grade 2 or higher colitis/diarrhea, early stool inflammatory markers (lactoferrin, calprotectin) may help stratify patients for endoscopy, and endoscopic confirmation of the diagnosis and severity should be considered before starting high-dose systemic glucocorticoids; abdominal imaging is reserved for dominant pain, fever, or bleeding and should not be done routinely for diarrhea alone. The AGA cautions that no validated severity index for ICI colitis exists and that symptoms correlate poorly with endoscopic, radiologic, and treatment-response severity, and that rapid progression over days can occur, particularly with ipilimumab. ICI colitis typically responds to high-dose systemic glucocorticoids at 0.5-2 mg/kg prednisone-equivalent daily tapered over 4-6 weeks (the AGA explicitly notes these doses and schedules have not been rigorously examined). If there is no improvement after 2-3 days, add infliximab or vedolizumab while continuing glucocorticoids; both are reasonable options for glucocorticoid-refractory colitis. Budesonide is ineffective as prophylaxis and is not a standard treatment for ICI colitis, it is reserved for ICI-associated microscopic colitis. Retreatment with immunotherapy is possible under select conditions. For hepatitis, obtain baseline liver chemistries (total bilirubin, alkaline phosphatase, AST, ALT) and HBV serologies before ICI; grade by CTCAE and manage as follows: grade 1 (AST/ALT 1-3x ULN or bilirubin 1-1.5x ULN), monitor liver chemistries 1-2 times weekly; grade 2 (AST/ALT >3-5x ULN or bilirubin >1.5-3x ULN), hold ICI until resolution to grade 1, and if symptomatic give prednisone 0.5-1.0 mg/kg/d or equivalent; grade 3 (AST/ALT >5-20x ULN or bilirubin >3-10x ULN), discontinue ICI and start methylprednisolone 1-2 mg/kg/d or equivalent; grade 4 (AST/ALT >20x ULN or bilirubin >10x ULN or hepatic decompensation), permanently discontinue ICI and start methylprednisolone 2 mg/kg/d. For ICI hepatitis that does not adequately improve after 3-5 days of high-dose glucocorticoids, escalate to a second-line immunosuppressant, mycophenolate mofetil (with azathioprine as an accepted alternative), while continuing glucocorticoids; infliximab is not recommended for ICI hepatitis because of its potential for hepatotoxicity. Evaluate all ICI-related liver-chemistry elevations for alternate etiologies (consider liver biopsy), and obtain biliary imaging when alkaline phosphatase and/or bilirubin are elevated.

American Gastroenterological Association (AGA), "AGA Clinical Practice Update on Diagnosis and Management of Immune Checkpoint Inhibitor Colitis and Hepatitis: Expert Review" (Dougan M, Wang Y, Rubio-Tapia A, Lim JK), Gastroenterology 2021;160(4):1384-1393 · reviewed 2026-07-23 ↗

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