Management of paediatric patients with medically-refractory Crohn's disease using Ustekinumab: A multi-centred cohort study.

Background: Ustekinumab (UST) is effective in the treatment of adults with moderate to severe Crohn's disease (CD). There is a paucity of data on its use in children.

Aim: To evaluate the response to UST in children with moderate to severe CD.

Methods: This multi-centre retrospective cohort study identified children under 18 years old with CD who received open-labelled subcutaneous UST. The primary outcome was changes in mean abbreviated PCDAI (aPCDAI) between baseline and 3 and 12 months, and rate of clinical remission at 3 and 12 months. Secondary outcomes were clinical response at the same time points, changes in C-reactive protein (CRP) and albumin, improvement in growth parameters and rate of adverse events.

Results: 44 patients who failed at least one biologic treatment were identified. Linear mixed model (LMM) analysis revealed a statistically significant effect of UST (χ2(1) =42.7, P = 1.2 x 10 -8) which lowered the aPCDAI scores by about 16 ± 2.7 at 3 months, and 19.6 ± 2.9 at 12 months. At 12 months, 38.6% of the patients achieved clinical remission and 47.8% achieved clinical response. There was a significant increase in mean weight z-scores of 0.48 (+/- 0.13) (P<0.001) and in mean BMI z score of 0.66 (+/- 0.16) (P<0.001). The probability of remaining on UST at 12 months was 76.9%. The rate of adverse events was 12.4 per 1000 patient-months.

Conclusion: Subcutaneous UST should be considered a viable therapeutic option for paediatric patients who are refractory to other biologic agents. Prospective randomized trials are needed.