Wide variation in the use and understanding of therapeutic drug monitoring for anti-TNF agents in inflammatory bowel disease: an inexact science?

ABSTRACT

Background: We aimed to understand the way in which therapeutic drug monitoring (TDM) is used, understood and interpreted for anti-TNF agents in IBD.

Research design and methods: We designed an 18-question survey that included 5 TDM-based clinical scenarios, for which the ‘most appropriate’ responses were based on the BRIDGe groups ‘Anti-TNF Optimizer’. This resource combines TDM evidence with expert consensus.

Results: We received 110 complete responses: 50 (45%) consultants, 30 (27%) trainees, 25 (23%) IBD nurse specialists and 5 (5%) gastroenterology pharmacists. Over half (61, 55%) only carry out TDM in non-response. The remainder use TDM routinely, including during stable maintenance therapy for patients in remission. Lower therapeutic thresholds used were variable. Most (82, 75%) were unsure whether their laboratory uses a drug-tolerant or drug-sensitive antidrug antibody assay and few (15, 14%) understand the difference. Consultants, high-frequency users (> 3requests/month) and clinicians with larger anti-TNF cohorts (> 100) were significantly more likely to select the ‘most appropriate’ answer to at least 1 of the 5 TDM-based clinical scenarios.

Conclusions: There exists marked heterogeneity in the practical use, understanding and interpretation of biologic TDM. Biologic decision-making, informed by TDM, should involve consultation with experienced clinicians who are frequent TDM users, ideally, as part of a multidisciplinary, biologics-focused IBD meeting.

Abbreviations: TDM: therapeutic drug monitoring; CNS: clinical nurse specialist; ELISA: enzyme-linked immunosorbent assay; RIA: radioimmunoassays; HMSA: homogenous mobility shift assays; BSG: British Society of Gastroenterology.

KEYWORDS:

• Biologics
• therapeutic drug monitoring
• infliximab
• adalimumab
• anti-TNF

Acknowledgments

The authors would like to thank the following people for their help in distributing our survey to the following groups:

Julie Duncan - IBD Clinical Nurse Specialists via the Royal College of Nursing IBD Network. Esha Sharma & Anja St.Clair-Jones - Gastroenterology Pharmacists via the gastroenterology special interest group of the UK Clinical Pharmacy Association. Barney Hawthorne, Howard Ellison, Christopher O’Shea - British Society of Gastroenterology members.

Declaration of interest

M Samaan has received advisory fees from Hospira, Takeda and Janssen; lecture fees from Hospira, Takeda, MSD, Janssen and Falk. Z Arkir has received lecture fees from Abbvie. T Ahmad has received advisory fees from Abbvie, Takeda, MSD, Celltrion Pharma, Pfizer, Roche, Janssen and Ferring; lecture fees from Abbvie, Janssen, Celltrion, Warner Chilcott, Falk Pharma and Takeda; financial support for research from MSD Abbvie, UCB, Warner Chilcott, Celltrion Pharma, NAPP, Hospira, Pfizer, Tillotts and Ferring. P Irving has received advisory fees from Abbvie, Warner Chilcott, Takeda, MSD, Vifor Pharma, Pharmacosmos, Topivert, Genentech, Hospira and Samsung Bioepis; lecture fees from Abbvie, Warner Chilcott, Ferring, Falk Pharma, Takeda, MSD, Johnson and Johnson, Shire; financial support for research from MSD and Takeda. The authors have no other relevant affiliations or financial involvement with any organization or entity with a financial interest in or financial conflict with the subject matter or materials discussed in the manuscript apart from those disclosed.

Reviewer Disclosures

Peer reviewers on this manuscript have no relevant financial relationships or otherwise to disclose.

Ethical Considerations

The Health Research Authority does not consider this type of survey of clinician groups, research and therefore suggests NHS REC approval is not necessary for our study.

Author Contributors

MA Samaan, Z Arkir and PM Irving were responsible for the original concept and planning of the study. MA Samaan, Z Arkir and PM Irving were responsible for data collection and analysis. MA Samaan drafted the manuscript, which Z Arkir, T Ahmad and PM Irving critically reviewed and revised. All authors have approved the final version of the manuscript and agree to be accountable for all aspects of the work

Supplementary material

Supplemental data for this article can be accessed here.

Additional information

Funding

This paper is not funded.