BACKGROUND AND OBJECTIVES: Ustekinumab (USTE) and vedolizumab (VEDO) are increasingly used in paediatric patients with inflammatory bowel diseases (pIBD). However, data on the usefulness of therapeutic drug monitoring (TDM) in children are scarce. The primary objective of this study was to evaluate the association between disease activity, measured by faecal calprotectin (F-CPT), and serum trough levels (TLs) of USTE and VEDO. Secondary outcomes were to explore factors potentially associated with the outcome and exposure, to determine the optimal USTE or VEDO dose that predicts remission (defined as F-CPT < 250 µg/g), to validate our hypothesis using a proof-of-concept cohort (POCC) and to assess the occurrence of serum antibodies to USTE and VEDO. METHODS: This was a prospective single-centre observational study performed at the University Hospital Motol, Prague, Czech Republic. Of the 87 patients (51 Crohn's disease (CD), 30 ulcerative colitis (UC), and 6 IBD unclassified (IBD-U)), drug serum TLs and antibodies were measured in 282 observations (49 treatment courses) of USTE and 359 observations (38 courses) of VEDO. Serum and stool samples were collected before each study drug application during both the induction and maintenance phases of the treatment throughout the entire study period (January 2020 to June 2024). Clinical and laboratory data were obtained from the nationwide prospective registry CREdIT. Patients with perianal disease and those with previous major bowel surgery were not excluded from the study. As a POCC, we analysed a group of pIBD treated at our centre with anti-TNF agents-adalimumab or infliximab. RESULTS: In a linear multiple regression mixed model, an association was observed between logF-CPT levels and USTE treatment duration (β -0.0010, 95% confidence interval (CI) -0.0015 to -0.0006, p < 0.001) but not with USTE TLs (p = 0.12). VEDO TLs and logF-CPT levels were negatively associated both in the linear (β -0.0173, 95% CI -0.0292 to -0.0053, p = 0.005) and categorical models (p = 0.026), even after adjusting for time. A VEDO TL of 15.1 µg/mL showed the best, though still poor, combination of sensitivity (0.82) and specificity (0.32) to predict F-CPT < 250 µg/g (area under the curve (AUC) 0.56, 95% CI 0.49-0.63). Intensification, induction phase, undetectable TLs, and type of IBD (CD, UC, IBD-U) were not associated with logF-CPT. Slightly elevated anti-drug antibodies were detected in 5 USTE and 16 VEDO observations, with no clinical implications. CONCLUSIONS: TDM of USTE does not appear to be useful in pIBD. TDM of VEDO may assist in therapeutic strategy decisions, although establishing clinically useful cut-offs remains challenging.

• Publication type
• Journal Article MeSH

BACKGROUND: There are scarce data available on upadacitinib in children with Crohn's disease (CD). AIM: To evaluate the effectiveness and safety of upadacitinib as an induction therapy in paediatric CD. METHODS: This 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. RESULTS: We 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. CONCLUSION: Upadacitinib is an effective induction therapy for refractory paediatric CD. Efficacy should be weighed against the potential risks of AEs.

• Keywords
• JAK inhibitors, children, inflammatory bowel disease,
• MeSH
• Crohn Disease * drug therapy   MeSH
• Child MeSH
• Heterocyclic Compounds, 3-Ring * therapeutic use   adverse effects   MeSH
• Remission Induction MeSH
• Humans MeSH
• Adolescent MeSH
• Retrospective Studies MeSH
• Treatment Outcome MeSH
• Check Tag
• Child MeSH
• Humans MeSH
• Adolescent MeSH
• Male MeSH
• Female MeSH
• Publication type
• Journal Article MeSH
• Multicenter Study MeSH
• Names of Substances
• Heterocyclic Compounds, 3-Ring * MeSH
• upadacitinib MeSH Browser

Ustekinumab is an effective therapy for adult Crohn's disease (CD), but data in paediatric CD patients are scarce. The aim of the study was to describe the real-life effectiveness and safety of ustekinumab in paediatric CD. This is a multicentre review of children with Crohn's disease treated with ustekinumab. The aim of our study was to describe the effectiveness and safety of ustekinumab in paediatric real-life practice. This is a study of the Paediatric IBD (inflammatory bowel disease) Porto group of ESPGHAN. Corticosteroid (CS)- and exclusive enteral nutrition (EEN)-free remission, defined as weighted Paediatric Crohn's Disease Activity Index (wPCDAI) < 12.5, and physician global assessment (PGA) were determined at weeks 12 and 52. A total of 101 children were included at a median age of 15.4 years (IQR 12.7-17.2) with a median follow-up of 7.4 months (IQR 5.6-11.8). Ninety-nine percent had received prior anti-TNF, 63% ≥ 2 anti-TNFα therapies and 22% vedolizumab. Baseline median wPCDAI was 39 (IQR 25-57.5) (71 (70%) patients with moderate-severe activity). Weeks 12 and 52 CS- and EEN-free remission were both 40.5%. Clinical response at week 6, iv induction route and older age at onset of ustekinumab treatment were predictive factors associated with clinical remission at week 12. Seven minor adverse events probably related to ustekinumab were reported. One patient died from an unrelated cause. Conclusion: Our results suggest that ustekinumab is effective and safe in children with chronically active or refractory CD. What is Known: • Ustekinumab is an effective therapy for adult moderate to severe Crohn's disease (CD). • Off-label use of ustekinumab in children is increasing especially in anti-TNF refractory CD. What is New: • Is the largest cohort of real-world use of ustekinumab in paediatric CD to date. • Clinical response at week 6, iv induction and older age at onset of ustekinumab were predictive factors associated with clinical response at week 12.

• Keywords
• Children, Crohn’s disease, Exclusive enteral nutrition, Ustekinumab, wPCDAI,
• MeSH
• Crohn Disease * drug therapy   MeSH
• Child MeSH
• Remission Induction MeSH
• Humans MeSH
• Adolescent MeSH
• Retrospective Studies MeSH
• Severity of Illness Index MeSH
• Ustekinumab * therapeutic use   MeSH
• Treatment Outcome MeSH
• Check Tag
• Child MeSH
• Humans MeSH
• Adolescent MeSH
• Male MeSH
• Female MeSH
• Publication type
• Journal Article MeSH
• Multicenter Study MeSH
• Names of Substances
• Ustekinumab * MeSH