Drug monitoring of biologics in inflammatory bowel disease

The monoclonal antibodies currently used for the treatment of inflammatory bowel disease (IBD) have been thoroughly studied with regard to efficacy and safety. Their pharmacokinetics and the considerable inter-individual variability of clearance and immunogenicity have attracted a great deal of attention recently. Knowledge about their properties carries the potential to optimize efficacy and durability of therapeutics that is a mainstay in the medical management of IBD.Based on population-based pharmacokinetics models, factors impacting the clearance of infliximab have been identified, antidrug antibodies (ADA) being one of them. Trough levels have been shown to correlate with clinical response and steroid-free remission. Initial insights have recently been gained into the individual course of ADA with a potential impact on future therapeutic strategies.We briefly review the current state of the literature and propose an algorithm for the use of serum trough levels and ADA as basis for monitoring of biologics in patients with IBD.