Therapeutic Drug Monitoring of Anti-TNF Therapy in Inflammatory Bowel Disease.

OPINION STATEMENT: While anti-TNF agents have had a marked impact in the treatment of inflammatory bowel disease, a significant number of patients lose their response to these medications over time. Clinical trials have demonstrated that antibodies against anti-TNF medications may impact treatment response and increase the risk of infusion reaction. Scheduled dosing and concurrent use of immunomodulators may help to mitigate these risks via inhibiting the formation of these antibodies. The recent availability of assays to measure anti-TNF drug levels and antibodies against anti-TNFs offer the opportunity to assess patients who have lost response with infliximab and adalimumab, and potentially determine the most appropriate therapeutic strategy. There is growing evidence that such testing improves patient outcomes and is cost-effective, although heterogeneity in the assays used in clinical and observational trials has resulted in mixed results.