Baseline Drug Clearance Predicts Outcomes in Children With Inflammatory Bowel Disease Treated With Vedolizumab: Results From the VedoKids Prospective Multicentre Study.

Background: The pharmacokinetics of biologic agents can differ between children and adults with inflammatory bowel disease (IBD), often necessitating modified paediatric dosing strategies.

Aims: To define the exposure-response relationship of vedolizumab in the paediatric IBD VedoKids cohort including the effect of baseline clearance on deep biochemical remission (normal C-reactive protein [CRP]/erythrocyte sedimentation rate [ESR] and steroid-free remission) at 30 weeks, and to use population pharmacokinetic models to find the best matches between adult and paediatric pharmacokinetic profiles.

Methods: We sought a pharmacokinetic model on 312 serum vedolizumab concentrations from 129 children, assisted by a published adult model as a Bayesian prior.