Finger prick test for adalimumab aids personalized dosing

Researchers from Sanquin and Reade (the Netherlands) can measure adalimumab levels in dried blood spots. These levels correlate well to serum levels. This was published in the British Journal of Clinical Pharmacology. At-home blood sampling of biologics may facilitate personalized dosing and an optimized use of biologics. At this moment no home-sampling test is available.

Adalimumab acts by blocking TNF and is used to treat inflammatory diseases such as rheumatoid arthritis, psoriatic arthritis, ankylosing spondylitis and inflammatory bowel diseases. Therapeutic drug monitoring of adalimumab enables personalized dosing to optimize therapy and cost-effective use of this much-prescribed drug. It could add to the QOL if patients sampled at home. Advance testing would provide the clinician with a serum level when the patient present themselves in the clinic and enables clinicians to advice from a distance.

Researchers of Sanquin and Reade developed a method to use dried blood spots to determine serum adalimumab accurately. They found that adalimumab levels eluted from dried blood spots obtained by finger prick correlate well to those obtained with venipuncture. The blood spots are very stable and can be stored for at least three months at room temperature.

Spot size

In this cross-sectional study 161 consecutive adalimumab-treated patients with rheumatic inflammatory diseases were included. A trained laboratory assistant performed venipuncture and finger prick at the same hospital visit. As adalimumab stays in the plasma and since plasma and serum values correlate to clinical efficacy, it was pivotal to convert adalimumab in whole-blood dried blood spots to serum values. Especially, because hematocrit and spot size differ between patients and moment of sampling. Besides adalimumab itself, also anti-adalimumab antibodies were determined accurately from dried blood spots.

Other biologics

Senior researcher Karien Bloem from Sanquin states this method could also be applied for therapeutic drug monitoring of other biologics. These therapeutics form a relatively new class of powerful drugs, adalimumab being the most widely used biologic. Circa one million patients are being treated with adalimumab worldwide. Easy home sampling at different time points will benefit patients and could help to prescribe biologics optimally. Bloem: ”There was an immediate interest and since clinicians learned about this opportunity clinical validation studies in pediatrics as well as IBD have started”.

Publication:

Dried blood spots from finger prick facilitate therapeutic drug monitoring of adalimumab and anti-adalimumab in patients with inflammatory diseases. E L Kneepkens, M F Pouw, G J Wolbink, T Schaap, M T Nurmohamed, A de Vries, T Rispens, K Bloem. Br J Clin Pharmacol. 2017 Aug 9