Effectiveness and safety of biosimilars in pediatric inflammatory bowel diseases: an observational longitudinal study on the French National Health Data System

Background: Data on biosimilar use in pediatric inflammatory bowel diseases (IBD) is scarce, as no clinical trial and few observational studies evaluating those products were conducted in this population.

Objectives: To evaluate effectiveness and safety of biosimilar products compared to originators in the real world.

Methods: We used data from the French National Health Data System (SNDS), covering 99% of the French population, to identify children (less than 18 years old at treatment initiation) initiating treatment with a biosimilar or originator product of infliximab (IFX) or adalimumab (ADA) for Crohn’s disease (CD) or ulcerative colitis (UC), from first biosimilar launch (January 2015 and October 2018 respectively) to 31 December 2022. Patients’ follow-up went until 30 June 2023. We compared the risks of treatment failure (treatment discontinuation or modification, dose escalation or IBD-related surgery) and of safety events (all-cause or infection-specific hospitalization for at least one night) in biosimilar versus originator new users using inverse probability of treatment weighted (IPTW) Cox regressions. Multiple sensitivity analyses were carried out varying the definition of the treatment failure, the follow-up duration. We also analyzed subgroups of biosimilar products, periods of initiation and treatment history.

Results: We included 5870 patients (infliximab: n = 3491; adalimumab: n = 2379) in the study. Biosimilars represented respectively 76·0% (n = 2652) and 29·0% (n = 691) of infliximab and adalimumab initiations. CD represented 70·9% (n = 2476) and 69·0% (n = 1642) of infliximab and adalimumab initiations. Biosimilar use was not associated with increased risks of treatment failure (IPTW HR [95% confidence interval, CI]: infliximab 0·92 [0·78-1·09] in CD, 0·98 [0·76-1·27] in UC; adalimumab 0·98 [0·85-1·14] in CD, 1·01 [0·82-1·24] in UC). Occurrence of all-cause hospitalisation was not different between exposure groups (IPTW HR [95% CI]: infliximab 0·96 [0·78-1·18]; adalimumab 1·03 [0·80-1·33]). No difference in occurrence of serious infections, mainly gastro-intestinal or dermatological, was found.

Conclusions: We provide reassuring results on the use, effectiveness and safety of biosimilars in a large unselected pediatric population suffering from IBD. Further works need to be carried in other pediatric immune-mediated inflammatory diseases.