Consider reactive TDM for biologics in inflammatory arthritis: EULAR

Rheumatoid arthritis

By Selina Wellbelove

23 May 2022

Clinicians can consider reactive therapeutic drug monitoring (TDM) as part of the management of inflammatory rheumatic and musculoskeletal diseases (RMDs) with biologics, but cost effectiveness “should be considered according to local context and standard of care”, according to new consensus guidelines.

The first EULAR-backed advice on TDM of biopharmaceuticals in patients with inflammatory RMDs aim to help raise awareness, increase understanding and better standardise its use in clinical practice across Europe.

Published in the Annals of the Rheumatic Diseases and led by Dutch rheumatologist Charlotte Krieckaert, the group of international authors noted a rising interest in TDM in rheumatology alongside a growing body of related evidence, but that “many rheumatologists are unaware of the pharmacokinetic properties of biopharmaceuticals and whether TDM-informed dosing may improve outcomes”.

Also, while validated assays for TDM are becoming more widely available, there is little guidance on how to use it in clinical practice, they said.

As such, a multidisciplinary taskforce from eight difference countries developed ‘points to consider’ on performing TDM of biopharmaceuticals specifically in inflammatory RMDs and how to correctly interpret the resulting data.

Following a consensus process, six overarching principles and 13 points to consider were formulated covering in whom, when, and how to use TDM in patients with inflammatory RMDs.

The guidelines stress that approaches used by clinicians should remain in line with international and national guidelines for the management of the respective disease, and that use of TDM should be part of a shared decision making process between the healthcare professional and patients.

Points to consider that received unanimous backing included the measurement of biopharmaceutical blood concentrations and antidrug antibodies, as well as advice on the factors determining blood concentrations and patient-specific factors that might influence pharmacokinetics.

The authors shied away from recommending use of biopharmaceutical blood concentrations to guide dosing despite an association with clinical response, given “the lack of an identified optimal range for most biopharmaceuticals in most indications”, nor did they recommend routine use of proactive TDM (scheduled testing irrespective of the clinical situation).

However, it was stressed in the paper that points-to-consider were derived from population-based data, and that patient and healthcare professionals’ views on TDM had not been widely explored and so should be a focus of future research, in addition to that focusing on the clinical utility of TDM in general and in specific scenarios including tapering or switching.

The authors also put forward scientific and educational agendas “to increase awareness and knowledge of pharmacokinetics and pharmacodynamics relevant to biopharmaceuticals, especially concerning minimal effective blood concentrations”.

Click here to read the overarching principles and points to consider in full in the Annals of the Rheumatic Diseases

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