Abstract
Objective. To identify (1) whether tumor necrosis factor inhibitor (TNFi) drug levels/anti-drug antibodies (ADAb) are associated with treatment response and disability in patients with psoriatic arthritis (PsA); and (2) the factors associated with TNFi drug levels.
Methods. Patients were recruited from a national multicenter prospective cohort with longitudinal serum samples and 28-joint count Disease Activity Scores (DAS28)/Health Assessment Questionnaire (HAQ) measurement over 12 months.
Results. Adalimumab (ADA) drug levels were significantly associated with ΔDAS28 (β 0.055, 95% CI 0.011–0.099; p = 0.014) and inversely with HAQ over 12 months (β −0.022, 95% CI −0.043 to −0.00063). Factors significantly associated with ADA drug levels were ADAb levels and body mass index.
Conclusion. Drug level testing in ADA-initiated PsA patients may be useful in determining treatment response/disability over 12 months.
Footnotes
M.J. is supported by an NIHR clinical lectureship and was a Medical Research Council (MRC) Clinical Training Fellow supported by the North West England MRC Fellowship Scheme in Clinical Pharmacology and Therapeutics, during which OUTPASS was established, which is funded by the MRC (grant number G1000417/94909), ICON, GlaxoSmithKline, AstraZeneca, and the Medical Evaluation Unit. This research was funded directly from a small grant from the NIHR Manchester Biomedical Research Unit (now NIHR BRC) to M.J. and was supported by Versus Arthritis (grant references 20380 and 20385). This report includes independent research funded by the NIHR BRC Funding Scheme. The views expressed in this publication are those of the author(s) and not necessarily those of the UK National Health Service, the NIHR, or the Department of Health.
- Accepted for publication July 8, 2019.
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