What is the recommended duration of biological therapy, such as infliximab (Infliximab) or adalimumab (Adalimumab), for patients with Inflammatory Bowel Disease (IBD) in India?

Recommended Duration of Biological Therapy for IBD in India

Biological therapy for inflammatory bowel disease (IBD) should be continued indefinitely in patients who respond to treatment, with annual reviews to assess ongoing need, safety, and efficacy. 1

Initial Assessment and Response Evaluation

• Patients should be evaluated for response to anti-TNF induction therapy between 8-12 weeks to determine the need to modify therapy 1
• For vedolizumab, response should be assessed between 10-14 weeks after initiation 1
• Patients who achieve symptomatic response with anti-TNF induction therapy should continue the same therapy to maintain complete remission 1

Maintenance Therapy Duration

• Long-term biological therapy is recommended for patients who respond to induction, as there is high-quality evidence supporting continued anti-TNF therapy to achieve and maintain complete remission 1
• Annual review of patients on biological therapies is recommended to assess ongoing need, safety and efficacy of treatment 1
• There is no defined optimal duration of therapy, as studies show approximately 50% or more of patients who discontinue biological therapy experience disease relapse, with the proportion increasing over time 2

Optimizing Therapy for Long-term Use

• In patients who have suboptimal response to anti-TNF induction therapy, dose intensification is recommended to achieve complete remission 1
• For patients who lose response during maintenance therapy, dose optimization is suggested to recapture complete remission 1
• Therapeutic drug monitoring (TDM) should inform dose optimization decisions, measuring both trough levels and anti-drug antibody titers 1, 3

Combination Therapy Considerations

• When starting anti-TNF therapy, combining it with a thiopurine or methotrexate is suggested over monotherapy to improve pharmacokinetic parameters and reduce immunogenicity 1
• For infliximab specifically, combination with methotrexate may reduce immunogenicity and increase the likelihood of maintaining therapy long-term 1
• Combination therapy is particularly beneficial in patients with HLA-DQA1*05 who are more likely to develop antibodies against both adalimumab and infliximab 1, 4

Factors Affecting Treatment Duration

• Clinical factors that may lead to earlier treatment discontinuation include:
  • Ulcerative colitis (higher rates of primary non-response) 4
  • Articular manifestations 4
  • Use of infliximab (higher rates of adverse events compared to other biologics) 4
• Disease duration does not appear to affect the proportional treatment effect of biologics in either Crohn's disease or ulcerative colitis 5

Common Pitfalls and Caveats

• Stopping immunomodulator monotherapy after a period of remission is associated with high relapse rates (approximately 75% within 5 years) 2
• Discontinuing anti-TNF therapy after achieving remission results in approximately 50% of patients maintaining remission at 24 months, but this proportion decreases over time 2
• Interrupted therapy may result in lower response rates upon re-treatment, with studies showing only 38-55% of patients regaining response after restarting therapy 1
• When switching between biologics due to loss of response, therapeutic drug monitoring should guide decisions, as switching is more effective when antibodies are detected, while dose increases are more effective when drug levels are low 1

Conclusion for Indian Context

While there are no India-specific guidelines on the duration of biological therapy for IBD, the international consensus supports continuous therapy with annual reviews for patients who respond to treatment. The decision to continue or withdraw therapy should be based on therapeutic drug monitoring, disease activity markers, and individual risk factors for relapse.