What is the approach for managing microscopic colitis with biologics, such as infliximab (Infliximab) or adalimumab (Adalimumab)?

Management of Microscopic Colitis with Biologics

For patients with microscopic colitis who are refractory to budesonide therapy, biologics such as anti-TNF agents (infliximab, adalimumab) or vedolizumab can be considered as effective treatment options, though evidence is limited to case series and observational studies.

Current Treatment Algorithm for Microscopic Colitis

1. First-line therapy: Budesonide (9 mg daily for induction, followed by maintenance at 6 mg daily or lower)

   • Budesonide is the only medication with strong evidence from controlled clinical trials 1
   • Most patients respond to initial budesonide therapy

2. For budesonide-refractory, dependent, or intolerant cases:

   • Consider biologic therapy as a second-line option 1, 2
   • Immunomodulatory drugs may be indicated in these cases

Evidence for Biologic Therapy in Microscopic Colitis

Efficacy Data

• A systematic review and meta-analysis found clinical remission rates of:
  • 66.1% at weeks 3-6
  • 54.2% at weeks 12-16 2
• Clinical response rates were:
  • 100% at weeks 3-6
  • 67.2% at weeks 12-16 2

Available Biologic Options

1. Anti-TNF agents:

   • Infliximab and adalimumab have been used in case series 2
   • The Spanish Microscopic Colitis Group recommends anti-TNF drugs for severe cases that fail to respond to corticosteroids or immunomodulators 3

2. Vedolizumab:

   • Used in several case series with favorable outcomes 2
   • May be considered for patients with contraindications to anti-TNF therapy

3. Other biologics:

   • Limited data exists for ustekinumab and JAK inhibitors in microscopic colitis

Special Considerations

Checkpoint Inhibitor-Induced Microscopic Colitis

• For microscopic colitis induced by checkpoint inhibitors (used in cancer treatment):
  • A more aggressive approach with early introduction of biologics is reasonable 4
  • These cases may be more severe and less responsive to standard therapy

Safety Considerations

• Most common adverse event with biologics is medication discontinuation (16.1% pooled incidence) 2
• No deaths attributable to biologic use have been reported in microscopic colitis patients 2
• Consider the benefit-risk profile, especially in elderly patients (microscopic colitis is more common in older populations) 1

Practical Approach to Biologic Therapy in Microscopic Colitis

1. Patient selection:

   • Confirm diagnosis with colonoscopy and biopsies from all parts of the colon 1
   • Document failure of or intolerance to budesonide therapy
   • Rule out other causes of persistent diarrhea

2. Choice of biologic:

   • Anti-TNF agents (infliximab, adalimumab) have the most clinical experience 3, 2
   • Consider vedolizumab in patients with contraindications to anti-TNF therapy

3. Monitoring:

   • Assess clinical response based on stool frequency and consistency
   • Consider follow-up colonoscopy with biopsies in partial responders

Limitations and Knowledge Gaps

• The overall quality of evidence for biologic use in microscopic colitis is very low 2
• Most studies are small case series rather than randomized controlled trials
• Long-term efficacy and safety data are lacking
• No specific biologics are FDA-approved for microscopic colitis
• Evidence-based guidelines are currently lacking due to insufficient data 5

While biologics show promise in treating budesonide-refractory microscopic colitis, treatment decisions should be made carefully given the limited evidence base. Randomized controlled trials are needed to better define the role of specific biologic agents in the management of microscopic colitis.