Pharmacokinetics of anti-TNF monoclonal antibodies in inflammatory bowel disease: Adding value to current practice.

Since anti-tumor necrosis factor (TNF) antibodies were introduced to treat patients with inflammatory bowel diseases, short- and long-term clinical and endoscopic endpoints can be achieved that were unreachable with conventional anti-inflammatory agents. Although a large proportion of patients (70-90%) initially respond to the treatment, remission rates after induction are still low (20-50%) and patients are at risk to lose response to the drug over time. This inter-individual variability in response is likely to be influenced by the observed inter-individual variability in pharmacokinetics. By extensively reviewing the literature, we evaluated the potential role of therapeutic drug monitoring to optimize dosing of anti-TNF drugs. Thereby we emphasize some of the pharmacokinetic cornerstones that can help to understand the observed concentration-effect relationship. After discussing some of the most commonly used assays to measure anti-TNF drug and anti-drug antibody concentrations, we reviewed the application of those tests and their potential clinical value in retrospective and prospective studies.