Ustekinumab for children and adolescents with inflammatory bowel disease at a tertiary children's hospital in Japan.

Background And Aim: Ustekinumab is a human monoclonal antibody targeting the p40 subunit of both interleukin-12 and interleukin-23 with reported efficacy to treat Crohn's disease. However, few studies have reported the use of ustekinumab for pediatric inflammatory bowel disease. This study aimed to assess the clinical efficacy and safety of ustekinumab in children and adolescents with inflammatory bowel disease.

Methods: Medical records of patients aged under 20 years with Crohn's disease or Crohn's disease-like inflammatory bowel disease who had received ustekinumab at a Japanese pediatric inflammatory bowel disease center were retrospectively reviewed for efficacy and safety. The primary outcome was the steroid-free clinical remission rate at weeks 26 and 52. The steroid-free remission rate beyond week 52 was also evaluated. Weighted pediatric Crohn's disease activity index and simple endoscopic score for Crohn's disease were used to assess disease activity.

Results: Seventeen patients were included (male : female = 8:9, A1a [diagnosed < 10 years old]:A1b [diagnosed ≥ 10 years old] = 8:9). All patients were on ustekinumab at week 26, and 9/10 continued treatment over 1 year. The steroid-free clinical remission rates were 59% at week 26, 50% at week 52, and 70% over 1 year. Three of eight children who underwent endoscopy after ustekinumab introduction achieved endoscopic remission. No serious adverse events were recorded during the study period.

Conclusions: Ustekinumab may be an effective and safe treatment option for pediatric and adolescent Crohn's disease and Crohn's disease-like inflammatory bowel disease patients having nonresponse or adverse reactions to anti-tumor necrosis factor agents.