“The addition of immunomodulators increases the efficacy of maintenance therapy with infliximab for up to one year in patients with Crohn’s disease who have not been previously treated with immunomodulators. However, there are questions about the effect of withdrawing immunomodulator therapy from these patients. David Drobne and colleagues studied the effects of treatment with infliximab and immunomodulators (co-treatment) and then immunomodulator withdrawal on long-term outcomes of patients, as well as trough levels of infliximab and formation of anti-infliximab antibodies (ATI). Reporting in Clinical Gastroenterology and Hepatology, they find that, in a retrospective analysis, withdrawal of immunomodulators after at least six months (median, 13 months) of co-treatment with infliximab does not reduce the trough levels of infliximab in patients with Crohn’s disease. Detectable trough levels of infliximab at the time of immunomodulator withdrawal are associated with long-term response.”
Some additional details:
This was a retrospective open-label cohort study with 223 patients and median followup of 34 months. At baseline, 65 received infliximab (IFX) monotherapy and 158 received co-therapy with an immunomodulator (46 methotrexate, 112 thiopurine). Immunomodulators were withdrawn “only in patients with durable response (ongoing clinical benefit with lasting disease control with low C-reactive protein [CRP] [below 10 mg/L]).” Among the 158 on co-therapy, 117 reached a durable response and had withdrawal of immunomodulator after >6 months of combination therapy (median time 13 months).
- At baseline, co-therapy patients, compared to monotherapy patients, had higher IFX trough levels (adjusted mean increase of 1.44-fold) and lower likelihood of antibodies to infliximab (ATI): 35/158 (22%) compared with 25/65 (38%), P=.01.
- When immunomodulator was withdrawn, IFX levels remained stable: before 3.2 mcg/mL compared with after 3.7 mcg/mL. However, 45 of 117 (38%) required increasing doses of IFX and 21 of 117 (18%) discontinued IFX.
- Trough levels of IFX and CRP were most strongly associated with response to IFX dosing on monotherapy.
- “Only 9 of 74 patients (12%) with detectable IFX trough levels at the time of immunomodulator withdrawal developed undetectable IFX trough levels during the subsequent follow-up.”
- None of the 27 patients with IFX trough level >5 mcg/mL at time of immunomodulator withdrawal lost response to IFX during median follow-up of 29 months.
Though the headlines covering this article have suggested that IFX levels will stay stable when immunomodulators are withdrawn after >6 months, the authors proposed algorithm only recommends withdrawal for those with IFX trough level >5 mcg/mL. In addition, the data showed that a large number of patients required dose escalation and/or lost detectable IFX levels. Despite their proposed algorithm to withdraw in this small group, the authors further backtrack in their conclusion: “a prospective parallel group trial during a period of 5-10 years in a large group of patients is required to ascertain the real long-term benefit to risk ratio of continuing combined infliximab and immunomodulator treatment.”
Bottomline: If a patient is doing well, withdrawing immunomodulator co-therapy still has risks. I worry that the misleading reporting of this article will result in detrimental outcomes.
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- More Lessons in TNF Therapy (Part 2) | gutsandgrowth
Disclaimer: These blog posts are for educational purposes only. Specific dosing of medications (along with potential adverse effects) should be confirmed by prescribing physician. This content is not a substitute for medical advice, diagnosis or treatment provided by a qualified healthcare provider. Always seek the advice of your physician or other qualified health provider with any questions you may have regarding a condition.