Clinical impacts of immunomodulator withdrawal from anti-tumor necrosis factor combination therapy in pediatric inflammatory bowel disease.

Objectives: Combination therapy consists of both anti-tumor necrosis factor (anti-TNF) and an immunomodulator (IMM) and has been shown to improve outcomes in patients with inflammatory bowel disease (IBD). This study assesses the impacts of IMM withdrawal from combination therapy to anti-TNF monotherapy in children with IBD.

Methods: This single-center retrospective cohort study included children with IBD initiated on combination therapy between 2014 and 2019 who discontinued the IMM. We evaluated whether IMM withdrawal impacts laboratory values and disease activity. Linear mixed effects models with random intercepts were used to compare differences between groups. Chi-square and Kruskal-Wallis tests were used for comparisons between patients who did and did not require subsequent escalation of therapy.

Results: One hundred and fifty-two patients discontinued the IMM which did not significantly affect disease activity. However, 18% of patients escalated therapy after IMM withdrawal, primarily due to low anti-TNF levels. Lower anti-TNF and higher erythrocyte sedimentation rate (ESR) and C-reactive protein (CRP) levels before IMM withdrawal were associated with subsequent escalation of therapy. Overall, there was no statistically significant effect on anti-TNF drug levels. Patients with Crohn's disease (CD) on infliximab (IFX) and methotrexate (MTX) who discontinued the IMM had an increase in mean ESR and CRP (p < 0.05).

Conclusions: IMM withdrawal from anti-TNF combination therapy may be considered safe in the setting of higher anti-TNF levels and normal serum inflammatory markers. Clinicians should consider assessing anti-TNF levels and inflammatory markers after IMM withdrawal, especially in patients with CD receiving IFX who discontinued MTX.