Abstract
This study aimed to evaluate endoscopic healing (EH) efficacy and the durability of infliximab (IFX) in combination therapy with IFX and AZA versus IFX monotherapy in pediatric patients with Crohn’s disease (CD). In this retrospective observational study, clinical remission (CR), biochemical remission (BR), EH, transmural healing (TH) after 1-year of treatment, IFX trough levels (TLs), antibodies-to-IFX (ATIs), and IFX durability of 108 patients receiving IFX therapy, who were grouped into AZA combo-therapy (combination therapy group) and IFX monotherapy (monotherapy group), were compared. Of 108 patients who received IFX therapy, 85 (78.7%) received AZA combo-therapy for ≥3 months, and 23 (21.3%) received IFX monotherapy. No significant differences were observed in CR and TH at 1-year between the groups. However, the BR (92.9% vs. 66.7%, p = 0.003) and EH (78.6% vs. 33.3%, p < 0.001) were higher in the combination therapy group than in the monotherapy group. Further, the proportion of patients with TLs above the therapeutic drug levels was significantly higher in the combination therapy group than in the monotherapy group (p = 0.023). ATI formation was also significantly lower in the combination therapy group than in the monotherapy group (25.0% vs. 52.2%, p = 0.025). Multivariable Cox proportional hazard regression analysis showed that ATI positivity (hazard ratio [HR] 5.33, 95% CI [confidence interval] 1.61–17.60, p = 0.006) and combination therapy with IFX and AZA (HR 0.13, 95% CI 0.03–0.51, p = 0.004) were associated with IFX durability. Kaplan–Meier survival curves revealed significantly higher IFX durability in the combination therapy group (log-rank test, p = 0.0026) than in the monotherapy group. Compared with IFX monotherapy, combination therapy with IFX and AZA was associated with higher EH rates and longer IFX durability in pediatric patients with CD.