In what clinical scenarios might I consider performing TDM?

In what clinical scenarios might I consider performing TDM?

Peter L. Lakatos, MD

Volume 1 | Issue 4

Runs 1:48

The introduction of tumour necrosis factor-α (TNF-α) antagonists has dramatically changed management of inflammatory bowel disease (IBD) and significantly improved patient outcomes over the past 15 years.(1) Originally given as episodic monotherapy in refractory IBD, TNF-α antagonists are now most often combined with immunomodulators as scheduled therapy, and they are used early in disease management in high-risk patients. Long-term use of TNF-α antagonists is, however, associated with a substantial rate of loss of response (about 40%), much of which may be attributed to changes in pharmacokinetics. Subtherapeutic drug levels can allow disease to relapse, promote sensitization (formation of antidrug antibodies [ADAs]), and increase the risk of adverse events, such as infusion reactions.(2) The paucity of therapeutic alternatives makes it imperative to develop strategies to address secondary failure with TNF-α antagonists.(1)

As Crohn’s disease and ulcerative colitis are progressive, lifelong diseases, it is critical that clinicians maximize the efficacy of biologic drugs, but not persist with therapies that are no longer effective. Incorporation of therapeutic drug monitoring (TDM) into clinical decision-making is a promising approach to managing this clinical challenge. TDM encompasses measurement of both drug levels and antidrug antibody levels, allowing their correlation with clinical efficacy endpoints. Still in development as a clinical tool, numerous uncertainties surround the use of TDM. These include optimal measurement methods and timing, relation of drug and ADA levels to clinical response, impact of immunosuppression, and interpretation of results.(2)


  1. Khanna R, Sattin BD, Afif W, et al. Review article: a clinician’s guide for therapeutic drug monitoring of infliximab in inflammatory bowel disease. Aliment Pharmacol Ther. 2013;38(5):447–59.
  2. Lichtenstein GR. Comprehensive review: antitumor necrosis factor agents in inflammatory bowel disease and factors implicated in treatment response. Therap Adv Gastroenterol. 2013;6(4):269–93.

Special Edition IBD Dialogue: Therapeutic Drug Monitoring in Clinical Practice 2014·Volume 01 is made possible by an unrestricted educational grant from…