Interpreting the multi-biomarker disease activity score in the context of tocilizumab treatment for patients with rheumatoid arthritis

• Published in: Rheumatology international Vol. 36; no. 2; pp. 295 - 300
• Main Authors: Reiss, William G., Devenport, Jenny N., Low, Jason M., Wu, George, Sasso, Eric H.
• Format: Journal Article
• Language: English
• Published: Berlin/Heidelberg Springer Berlin Heidelberg 01-02-2016; Springer Nature B.V
• Subjects: Adult; Aged; Antibodies, Monoclonal, Humanized - therapeutic use; Antirheumatic Agents - therapeutic use; Arthritis, Rheumatoid - blood; Arthritis, Rheumatoid - diagnosis; Arthritis, Rheumatoid - drug therapy; Biomarkers - blood; Blood Proteins - metabolism; Disability Evaluation; Female; Humans; Inflammation Mediators - blood; Male; Medicine; Medicine & Public Health; Methotrexate - therapeutic use; Middle Aged; Predictive Value of Tests; Rheumatology; Severity of Illness Index; Short Communication - Validation Studies; Treatment Outcome; C-reactive protein (CRP); Biomarker; Interleukin-6 (IL-6); Tocilizumab; Rheumatoid arthritis; MBDA
• ISSN: 0172-8172; 1437-160X
• DOI: 10.1007/s00296-015-3285-2

The multi-biomarker disease activity (MBDA) score measures 12 proteins involved in the pathophysiology of rheumatoid arthritis (RA) to assess disease activity (DA). Previous studies demonstrated correlations between MBDA and clinical DA scores with some RA therapies. In this analysis, the relationship between DA and MBDA scores and changes in MBDA component biomarkers were evaluated in tocilizumab (TCZ)-treated patients. Patients from the ACT-RAY study were included in this analysis if they had DA measures and serum collected at pre-specified time points with sufficient serum for MBDA testing at ≥1 visit. Descriptive statistics, associations between outcomes, and percentage agreement between DA categories were calculated. Seventy-eight patients were included and were similar to the ACT-RAY population. Correlations between MBDA score and DAS28-CRP were
ρ
 = 0.50 at baseline and
ρ
 = 0.26 at week 24. Agreement between low/moderate/high categories of MBDA score and DAS28-CRP was observed for 77.1 % of patients at baseline and 23.7 % at week 24. Mean changes from baseline to weeks 4, 12, and 24 were proportionately smaller for MBDA score than DAS28-CRP. Unlike some other MBDA biomarkers, interleukin-6 (IL-6) concentrations increased in most patients during TCZ treatment. Correlations and agreement between MBDA and DAS28-CRP or CDAI scores were lower at week 24 versus baseline. The proportionately smaller magnitude of response observed for MBDA score versus DAS28-CRP may be due to the influence of the increase in IL-6 concentrations on MBDA score. Thus, MBDA scores obtained during TCZ treatment should be interpreted cautiously and in the context of available clinical information.