Therapeutic drug monitoring of biologics in IBD

May 22, 2018 - E-Mentoring in IBD | Volume 11 • 2018

Issue 10

Clinical Question

What are the evidence-based recommendations and/or expert opinions about the practice of therapeutic drug monitoring (TDM) of infliximab (IFX) or adalimumab (ADA) in IBD?

Editor’s Bottom Line

Therapeutic drug monitoring is a useful tool for clinical practice, but longitudinal intervention studies are still needed to confirm its effectiveness.


Mitrev N, Vande Casteele N, Seow CH, et al; IBD Sydney Organisation and the Australian Inflammatory Bowel Diseases Consensus Working Group. Review article: consensus statements on therapeutic drug monitoring of anti-tumour necrosis factor therapy in inflammatory bowel diseases. Aliment Pharmacol Ther. 2017 Dec;46(11–12):1037–53.


Following a systematic literature review of anti-TNF therapy and TDM in IBD with evidence graded according to the Australian NHMRC* guidelines, the 5-member steering committee developed an initial set of statements which were revised throughout a modified Delphi process. Selected based upon their publications, expertise, and leadership, the 25 voting members (steering committee and panellists), participated in the first 2 rounds of online voting while only 22 participated in the third in-person round. Consensus (≥80% agreement) was reached on 22 of 24 statements.

Based upon the evidence and recommendations, the authors also proposed clinical algorithms incorporating TDM for patients on anti-TNF with active and quiescent disease. Briefly:

  • TDM should be considered to inform patient management shortly after achieving remission, primary non-response, secondary loss of response, protracted remission, and prior to a drug holiday.
  • If a patient develops symptoms while on anti-TNFs, objective measures (endoscopy) should be employed to confirm IBD activity before treatment modification.
  • While on anti-TNF therapy, patients with either active or quiescent disease should be assessed for TDM levels, anti-drug antibodies, and adherence before treatment modifications such as switching to either an out-of- or within-class drug, addition of an immunosuppressant, or dose escalation.
  • TDM steady state targets for luminal disease are:
    • IFX: 3-8 µg/ml with some variation
    • ADA: 5-12 µg/ml with some variation
  • Anti-drug antibody assays should include quantitative titres and should be repeated to exclude transient positivity.
* National Health Medical Research Council


Study Design: Systematic literature review, recommendations developed using a modified Delphi with 3 iterations
Funding: Gastroenterological Society of Australia (GESA)
Allocation: n/a
Setting: n/a
Level of Evidence: 2b (Oxford Levels of Evidence)

The summary and conclusion in this issue of E-mentoring in IBD pertains to the manuscript(s) being reviewed, and should be considered in the context of what is already known surrounding the topic and incorporated into practice as deemed appropriate by the individual learner.