Infliximab Clearance in Children: Potential Association with Resting Energy Expenditure -

Objectives: Previous data suggest an inverse relationship between monoclonal antibody clearance and age in children. Furthermore, immunoglobulin clearance has been associated with metabolic rate; thus we evaluated the relationship between clearance and resting energy expenditure of infliximab in 117 patients with juvenile idiopathic arthritis. Methods: Standard linear and non-linear regression paradigms were used to explore the associations between age and infliximab clearance as well as resting energy expenditure and infliximab clearance by analyzing pharmacokinetic data for infliximab from a previous study in children with juvenile idiopathic arthritis (n = 117, age 4 to 17 years). Results: A significant inverse association between age and serum clearance (r2 = 0.21, p < 0.001) was appreciated. An association between resting energy expenditure and infliximab serum clearance revealed a significant positive linear association (r2 = 0.37, p < 0.001). Conclusion: These data suggest that age-dependence in infliximab serum clearance may be explained by expected developmental differences in resting energy expenditure.