Maintenance-phase serum anti-TNF levels are not associated with mucosal healing in pediatric Crohn's disease

Objectives: Mucosal healing (MH) is a key therapeutic target in Crohn's disease (CD) and is associated with improved outcomes. While adult studies indicate a positive correlation between serum anti-tumor necrosis factor (TNF) levels and MH, data in pediatric patients is limited. We aimed to define the association of serum anti-TNF levels with MH in pediatric patients with CD during maintenance therapy. Methods: Retrospective data (2014–2023) was collected from pediatric CD patients treated with infliximab or adalimumab who performed an ileocolonoscopy at least 26 weeks after initiating therapy. Serum anti-TNF levels around endoscopic time were compared with endoscopic findings. MH was defined as complete absence of inflammatory or ulcerative lesions across all segments of the gastrointestinal tract. Univariable and multivariable logistic regression analysis was conducted to identify factors associated with MH. Results: Data were obtained from 107 patients (41 infliximab and 66 adalimumab), with a median age at diagnosis of 12.6 (9.9–14.0) years. Median time until ileocolonoscopy following anti-TNF initiation was 89.0 (56.3–152.3) weeks. MH was identified in 31 (29.0%) patients. Anti-TNF serum levels were comparable in the MH and non-MH groups (9.5 [4.9–13.9] vs. 9.3 [6.4–15.7] µg/mL; p = 0.73), without differences in patients treated with infliximab or adalimumab. In multivariable analysis, diagnosis weight Z-score (odds ratio [OR] = 2.860, 95% confidence interval [CI] = 1.005–8.138; p = 0.049), along with C-reactive protein (OR = 0.037, 95% CI = 0.002–0.687; p = 0.027) and fecal calprotectin (OR = 0.995, 95% CI = 0.990–1.000; p = 0.037) at time of ileocolonoscopy were significantly associated with MH. Conclusions: In our cohort, anti-TNF levels during maintenance were not associated with MH in pediatric CD.