Session Type: ACR Poster Session C
Session Time: 9:00AM-11:00AM
Measurement of serum drug levels can help clinicians tailor treatment with TNF-inhibitors.
An association between certolizumab pegol (CP) serum levels and response has previously been found in patients (pts) with rheumatoid arthritis (1). Data for pts with axial spondyloarthritis (axSpA) are lacking. Here, we examine the association between serum CP levels and treatment response in pts with axSpA and tentatively identify a therapeutic target level.
Patients with a clinical diagnosis of axSpA starting standard treatment with CP included in the NOR-DMARD study with biobank sample at 3 months follow-up, were included in the present analyses. Serum drug levels (non-trough) were analysed with an in-house immunofluorometric assay automated on the AutoDELFIA immunoassay platform.
Associations between CP level and improvement in ASDAS-CRP and response (defined as ASDAS clinically important improvement (CII)) were assessed by multivariable linear and logistic regression (adjusting for age, sex and prior bDMARD (Y/N)), respectively.
Median serum drug level at 3 month follow up was 35.0 mg/L (IQR 21.3-45.3) in 116 pts. Response data were available in 110/116 patients.
Serum CP level ≥20 mg/L was associated with improvement in ASDAS at 3 months (β=0.55, (95% CI 0.12-1.98), P=0.01). Serum CP level ≥20 mg/L was associated with ASDAS CII at 3 months (OR 3.4 (95% CI 1.0-11.1, P=0.045)).
Only 18.2 % of pts with CP level <20 mg/L achieved ASDAS CII at 3 months, while 53.2% of pts with CP level 20-40 mg/L and 36.6 % with ≥40 mg/L were responders.
Serum CP level was associated with clinical response after 3 months of treatment in pts with axSpA. We suggest 20 mg/L as a lower target level for non-trough samples. No additional benefit of having a certolizumab level over 40 mg/L was observed. These results suggest that a therapeutic level of 20-40 mg/L can be implemented in clinical practice for non-trough serum samples in pts with axSpA.
1. Jani M et al. Ann Rheum Dis 2017;76(1):208-13.
To cite this abstract in AMA style:Gehin J, Syversen SW, Goll GL, Warren DJ, Sexton J, Kvein Strand E, Kvien T, Lie E, Bolstad N. Certolizumab Pegol Serum Levels ≥20 Mg/L Are Associated with Treatment Response in Patients with Axial Spondyloarthritis [abstract]. Arthritis Rheumatol. 2018; 70 (suppl 10). https://acrabstracts.org/abstract/certolizumab-pegol-serum-levels-%e2%89%a520-mg-l-are-associated-with-treatment-response-in-patients-with-axial-spondyloarthritis/. Accessed February 26, 2020.
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