What is the treatment for immune-mediated colitis?

Treatment of Immune-Mediated Colitis

For immune-mediated colitis, the first-line treatment is corticosteroids, with infliximab or vedolizumab recommended for steroid-refractory cases, as these biologics significantly reduce symptom duration and improve steroid taper success. 1

Diagnosis and Assessment

Before initiating treatment, proper diagnosis is essential:

• Check stool for infections (culture, C. difficile, parasites, CMV, viral etiologies)
• Test for fecal lactoferrin and calprotectin to determine disease activity
• Consider endoscopy with biopsy for patients with positive stool inflammatory markers
• CT scan of abdomen/pelvis may be needed to rule out complications like perforation or abscess

Treatment Algorithm Based on Severity

Mild (Grade 1) Colitis

• Characterized by <4 bowel movements per day above baseline
• Management:
  • Hydration
  • Consider holding immunotherapy
  • Monitor closely for worsening symptoms
  • Loperamide or diphenoxylate/atropine may be used cautiously
  • If diarrhea persists >2-3 days, proceed with infection workup and fecal lactoferrin testing
  • If lactoferrin positive, treat as moderate colitis

Moderate to Severe (Grade 2+) Colitis

• Characterized by ≥4 bowel movements per day above baseline and/or abdominal pain, blood in stool
• Management:

  1. Corticosteroids: First-line therapy 1

     • Prednisone 1-2 mg/kg/day or equivalent
     • Continue until symptoms improve to grade 1 or less, then taper over 4-6 weeks

  2. For steroid-refractory cases (symptoms persist >3-5 days on steroids):

     • Infliximab: 5 mg/kg IV 1, 2

       • May require multiple doses (typically at weeks 0,2, and 6)
       • Screening for TB, hepatitis B, and HIV recommended before starting

     • Vedolizumab: Alternative for patients who don't respond to infliximab 1

       • More gut-specific immunosuppression
       • May theoretically preserve anti-tumor immune responses

Important Clinical Considerations

• Introduction of biologics (infliximab or vedolizumab) within 10 days of colitis onset reduces symptom duration and improves steroid taper success 1
• Treatment with ≥3 doses of infliximab or vedolizumab and achieving endoscopic/histologic remission lowers risk of colitis relapse 1
• Endoscopic remission is often a better predictor of cure than clinical remission alone 1
• NSAIDs may increase the risk of immune checkpoint inhibitor-induced colitis and should be avoided 1
• For patients with ulcerative colitis receiving biologics, the American Gastroenterological Association suggests combining TNF antagonists with immunomodulators rather than TNF antagonist monotherapy 1

Monitoring Response

• Follow fecal calprotectin levels to monitor disease activity
• Consider repeat endoscopy to confirm mucosal healing, especially before resuming immunotherapy
• Mucosal healing on endoscopy and/or fecal calprotectin ≤116 mg/g can be considered treatment targets 1

Treatment-Resistant Cases

For cases resistant to steroids, infliximab, and vedolizumab:

• Fecal microbiota transplantation may be considered as a rescue therapy 1
• Consider other immunosuppressive agents in consultation with gastroenterology specialists

By following this treatment algorithm and promptly escalating therapy when needed, most cases of immune-mediated colitis can be effectively managed with improvement in morbidity, mortality, and quality of life outcomes.