Review article: consensus statements on therapeutic drug monitoring of anti-tumour necrosis factor therapy in inflammatory bowel diseases.

Background Therapeutic drug monitoring ( TDM) in inflammatory bowel disease ( IBD) patients receiving anti-tumour necrosis factor ( TNF) agents can help optimise outcomes. Consensus statements based on current evidence will help the development of treatment guidelines. Aim To develop evidence-based consensus statements for TDM-guided anti- TNF therapy in IBD. Methods A committee of 25 Australian and international experts was assembled. The initial draft statements were produced following a systematic literature search. A modified Delphi technique was used with 3 iterations. Statements were modified according to anonymous voting and feedback at each iteration. Statements with 80% agreement without or with minor reservation were accepted. Results 22/24 statements met criteria for consensus. For anti- TNF agents, TDM should be performed upon treatment failure, following successful induction, when contemplating a drug holiday and periodically in clinical remission only when results would change management. To achieve clinical remission in luminal IBD, infliximab and adalimumab trough concentrations in the range of 3-8 and 5-12 μg/mL, respectively, were deemed appropriate. The range may differ for different disease phenotypes or treatment endpoints-such as fistulising disease or to achieve mucosal healing. In treatment failure, TDM may identify mechanisms to guide subsequent decision-making. In stable clinical response, TDM-guided dosing may avoid future relapse. Data indicate drug-tolerant anti-drug antibody assays do not offer an advantage over drug-sensitive assays. Further data are required prior to recommending TDM for non-anti- TNF biological agents. Conclusion Consensus statements support the role of TDM in optimising anti- TNF agents to treat IBD, especially in situations of treatment failure. [ABSTRACT FROM AUTHOR]