Therapeutic drug monitoring in inflammatory bowel disease: The dawn of reactive monitoring

Table 3 Recommendations and statements made by various gastroenterology guidelines and consensus groups

Guideline/Consensus group	Recommendation
AGA[18,19]	Active IBD with anti-TNF → suggest use of reactive TDM
	Quiescent IBD with anti-TNF → not recommended
Inflammatory bowel disease Sydney/Australian Inflammatory bowel disease consensus working group (2017)[20]	Use of TDM preferred in (1) Upon suspected treatment failure; (2) Following successful induction; and (3) When completed drug holiday
	For those in clinical remission, consider TDM periodically only if it will change management
British guidelines (2019)[21]	Good practice recommendation → ALL IBD patients should be reviewed 2-4 wk post loading dose to assess response and check drug levels and anti-drug antibodies
	Use of serum drug trough & anti-drug antibody concentrations to be incorporated when deciding in change of therapy (dose escalation vs switch to other anti-TNF drug or out of class change)
ECCO (2020)[22]	CD in remission on anti-TNF → insufficient evidence to recommend FOR or AGAINST TDM
	CD patients who have lost response → insufficient evidence

AGA: American Gastroenterology Association; ECCO: European Colitis & Crohn’s Organization; TDM: Therapeutic drug monitoring; TNF: Tumor necrosis factor; IBD: Inflammatory bowel disease.