Therapeutic drug monitoring guided anti-tumour necrosis factor therapy in inflammatory bowel disease (IBD): Gastroenterological Society of Australia (GESA)/ Australian IBD Association (AIBDA) consensus statements

Abstract

INTRODUCTION: Growing evidence supports the use of therapeutic drug monitoring (TDM) to guide anti-tumour necrosis factor (TNF) drug treatment among patients with inflammatory bowel disease (IBD). Currently, TDM for anti-TNF drugs is variably practiced by gastroenterologists in Australia. Our aim was to develop consensus statements for TDM of anti-TNF drugs in IBD that will be endorsed by the Australian IBD Association (AIBDA) of the Gastroenterological Society of Australia (GESA). METHODS: A consensus committee of 25 Australian and international experts was assembled. A systematic literature search aided the steering committee in developing the initial draft statements. A modified Delphi technique was used with three iterations, with modification of statements based on feedback and anonymous voting. Statements with 80% agreement without reservation or only minor reservation in the third voting round were accepted as consensus. RESULTS: 22/24 statements met criteria for consensus. The committee agreed that TDM for anti-TNF agents 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 μg/mL and 5-12 μg/mL, respectively, were determined as appropriate. The therapeutic range may need to be altered for different disease phenotypes or treatment endpoints. In treatment failure, TDM may identify mechanisms to guide subsequent decisionmaking. Among patients in remission, TDM-guided anti-TNF drug dose optimisation may reduce treatment cost and avoid future relapse. Data indicates drug-tolerant antidrug antibody assays do not offer an advantage over drug-sensitive assays in 7 predicting outcomes. Further data are required prior to recommending TDM for nonanti- TNF biologics. CONCLUSION: These consensus statements are expected to aid use of TDM by gastroenterologists in Australia and abroad to guide anti-TNF drug treatment in IBD patients.