BackgroundThere are scarce data available on upadacitinib in children with Crohn's disease (CD).AimTo evaluate the effectiveness and safety of upadacitinib as an induction therapy in paediatric CD.MethodsThis was a multicentre retrospective study between 2022 and 2024 of children treated with upadacitinib for induction of remission of active CD conducted in 30 centres worldwide affiliated with the IBD Interest and Porto group of the ESPGHAN. We recorded demographic, clinical and laboratory data and adverse events (AEs) at week 8 post-induction. The analysis of the primary outcome was based upon the intention-to-treat (ITT) principle.ResultsWe included 100 children (median age 15.8 [interquartile range 14.3-17.2]). All were previously treated with biologic therapies including 89 with ≥ 2 biologics. At the end of the 8-week induction period, we observed clinical response, clinical remission and corticosteroid- and exclusive enteral nutrition-free clinical remission (CFR) in 75%, 56% and 52%, respectively. By the end of induction, 68% had achieved normalisation of C-reactive protein, and 58% had faecal calprotectin (FC) < 150 mcg/g. There was combined CFR and FC remission in 13/31 children with available data at 8 weeks (13% of the ITT population). AEs were recorded in 24 children; the most frequent was acne in 12. Two AEs (severe acne and hypertriglyceridemia) led to discontinuation of therapy.ConclusionUpadacitinib is an effective induction therapy for refractory paediatric CD. Efficacy should be weighed against the potential risks of AEs.