Appropriate Therapeutic Drug Monitoring of Biologic Agents for Patients With Inflammatory Bowel Diseases

Clin Gastroenterol Hepatol. 2019 Aug;17(9):1655-1668.e3. doi: 10.1016/j.cgh.2019.03.037. Epub 2019 Mar 27.


Background & aims: Therapeutic drug monitoring (TDM) is widely available for biologic therapies in patients with inflammatory bowel disease (IBD). We reviewed current data and provided expert opinion regarding the clinical utility of TDM for biologic therapies in IBD.

Methods: We used a modified Delphi method to establish consensus. A comprehensive literature review was performed regarding the use of TDM of biologic therapy in IBD and presented to international IBD specialists. Subsequently, 28 statements on the application of TDM in clinical practice were rated on a scale of 1 to 10 (1 = strongly disagree and 10 = strongly agree) by each of the panellists. Statements were accepted if 80% or more of the participants agreed with a score ≥7. The remaining statements were discussed and revised based on the available evidence followed by a second round of voting.

Results: The panel agreed on 24 (86%) statements. For anti-tumor necrosis factor (anti-TNF) therapies, proactive TDM was found to be appropriate after induction and at least once during maintenance therapy, but this was not the case for the other biologics. Reactive TDM was appropriate for all agents both for primary non-response and secondary loss of response. The panellists also agreed on several statements regarding TDM and appropriate drug and anti-drug antibody (ADA) concentration thresholds for biologics in specific clinical scenarios.

Conclusion: Consensus was achieved towards the utility of TDM of biologics in IBD, particularly anti-TNF therapies. More data are needed especially on non-anti-TNF biologics to further define optimal drug concentration and ADA thresholds as these can vary depending on the therapeutic outcomes assessed.

Keywords: Anti-TNF; Consensus Statement; Crohn’s Disease; Immunogenicity; Ulcerative Colitis; Ustekinumab; Vedolizumab.

Publication types

  • Consensus Development Conference
  • Research Support, N.I.H., Extramural
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Antibodies / immunology*
  • Antibodies, Monoclonal, Humanized / immunology
  • Antibodies, Monoclonal, Humanized / therapeutic use
  • Biological Products / immunology
  • Biological Products / therapeutic use
  • Delphi Technique
  • Drug Monitoring / standards*
  • Gastrointestinal Agents / immunology
  • Gastrointestinal Agents / therapeutic use*
  • Humans
  • Immunologic Factors / immunology
  • Immunologic Factors / therapeutic use*
  • Inflammatory Bowel Diseases / drug therapy*
  • Natalizumab / immunology
  • Natalizumab / therapeutic use
  • Treatment Outcome
  • Tumor Necrosis Factor Inhibitors / immunology
  • Tumor Necrosis Factor Inhibitors / therapeutic use*
  • Ustekinumab / immunology
  • Ustekinumab / therapeutic use


  • Antibodies
  • Antibodies, Monoclonal, Humanized
  • Biological Products
  • Gastrointestinal Agents
  • Immunologic Factors
  • Natalizumab
  • Tumor Necrosis Factor Inhibitors
  • vedolizumab
  • Ustekinumab