medwireNews: Changes in the multi-biomarker disease activity (MBDA) score could be used to track response to rituximab treatment in patients with rheumatoid arthritis (RA), researchers report.
The DAS28 score “is one of the most frequently used composite scores for the assessment of disease activity in clinical studies of RA,” but “has shortcomings that hamper its use in clinical practice,” such as the use of subjective components and its lack of ability to detect extra-articular inflammation, say the researchers.
“Thus, there is a need for an objective measure that reflects systemic disease activity and is sensitive to change,” they write in Arthritis Research & Therapy.
Nadia Roodenrijs (University Medical Center Utrecht, the Netherlands) and study co-authors explain that the MBDA score is calculated using levels of 12 serum biomarkers to generate a score between 1 and 100 points, with a higher score indicating worse disease activity.
Among 57 rituximab-treated RA patients from three cohorts, the median MBDA score improved from 54.0 points at baseline to 51.0 points 6 months after initiating treatment with the B-cell depleting agent. The corresponding DAS28-ESR scores were 6.3 and 5.0 points.
The researchers identified a significant correlation between MBDA and DAS28-ESR scores at both baseline and at the 6-month follow-up, with correlation coefficients of 0.52 and 0.49, respectively, and similar results were observed using the DAS28-CRP score.
When the team analyzed components of the DAS28 score separately, the MBDA score was significantly correlated with ESR and CRP, but not with swollen and tender joint counts, suggesting that the correlation “seems predominantly dependent on the biochemical components of the DAS28.”
Change in MBDA score over the study period was also significantly associated with the probability of achieving a moderate or good EULAR response among the rituximab-treated patients, with each unit increase in MBDA score conferring an 11% lower probability of achieving such a response after adjustment for factors including age, sex, smoking, and autoantibody positivity.
Roodenrijs and team did not identify a significant correlation between MBDA score and radiographic progression (mTSS score worsening of ≥5 points), which they attribute to the small number of patients who experienced radiographic progression (n=11), as well as the “limited observation period.”
Together, these results indicate that the MBDA score “tracked disease activity in RA patients treated with rituximab and that change in MBDA score reflected the degree of treatment response,” say the investigators.
They conclude: “Our findings are consistent with previous research in RA patients treated with other DMARDs.”
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