Infliximab originator and biosimilars have similar efficacy in children with inflammatory bowel disease

Abstract Objectives To evaluate whether children with inflammatory bowel disease (IBD) who initiate infliximab originator versus biosimilar experience similar clinical outcomes at 12 months. Methods We conducted a retrospective cohort study evaluating prospectively collected data from the ImproveCareNow (ICN) Network registry. Children <18 years old initiating infliximab originator or biosimilar between January 2016 and September 2022 were eligible. Matched groups initiating originator and biosimilar were created with propensity score matching based on age at initiation, sex, race, year therapy initiated, and IBD type. Clinical disease activity, growth, and laboratory values were assessed at 12 months between the two groups using χ 2 , Fisher's exact test, or Wilcoxon rank sum test. Cox proportional hazard models were created to compare time to drug discontinuation, hospitalizations, and surgery between the two groups. Results After propensity score matching, 428 children were included, 214 originator and 214 biosimilar starters. Efficacy at 12 months was similar as assessed by steroid‐free clinical remission ( p = 0.25), height‐ z ‐score ( p = 0.68), hematocrit ( p = 0.37), albumin ( p = 0.40), and erythrocyte sedimentation rate ( p = 0.06). Time to infliximab discontinuation ( p = 0.21), time to surgery ( p = 0.79), and time to hospitalization ( p = 0.66) were comparable between infliximab originator and biosimilar users. Fecal calprotectin values were statistically higher ( p = 0.032) at 12 months in patients started on the infliximab biosimilar versus originator, but only 30% of patients had values. Conclusion This is one of the largest, multicenter studies to evaluate infliximab biosimilar use. Rigorous propensity score‐matched methods demonstrated no differences in outcomes or treatment durability between children with IBD initiating infliximab originator or biosimilars.