Tracked changes in the multi-biomarker disease activity (MBDA) scores of patients with rheumatoid arthritis (RA) reflect changes in the degree of rituximab treatment response, according to study results published in Arthritis Research & Therapy.
The validity of using MBDA scores to measure disease activity and treatment response to a number of disease-modifying antirheumatic drugs (DMARDs) in patients with RA has been demonstrated in other studies, but this has previously not been done with rituximab.
Researchers in this study compiled data from 3 cohorts of patients with RA (n=57) treated with an intravenous infusion of 100 mg methylprednisolone followed by an infusion of 1000 mg rituximab at day 1 and day 15. Although these 3 cohort studies followed patients for a year post-baseline, the current study was limited to data from the initial 6 months to avoid potential confounding effects that repeated rituximab infusions could have in some study participants.
Spearman’s rank correlation coefficient calculations between participants’ MBDA scores and various tests to measure disease activity and quality of life were made for the values at baseline, 6-months, and the changes from baseline to 6 months. Then, using MBDA scores as independent variables and disease activity/quality of life measures as dependent variables, investigators performed multivariable linear regression analyses with adjustment for confounders. Also adjusting for relevant confounders, researchers calculated the association between the change from baseline to 6 months and 6-month response as measured by the European League Against Rheumatism (EULAR).
The baseline median MBDA score was 54.0 (interquartile range [IQR], 44.3-70.0), and the baseline median 28-joint Disease Activity Score using erythrocyte sedimentation rate (DAS28-ESR) score was 6.3 (IQR, 5.4-7.1). Participants’ MBDA scores correlated significantly with high-sensitivity C-reactive protein (hsCRP), ESR, DAS28-ESR, and DAS28-hsCRP at baseline and 6 months, and the change in MBDA scores from baseline to 6 months was significantly correlated with changes in those same measures. Changes in MBDA score from baseline to 6 months were associated with good or moderate EULAR response (adjusted odds ratio 0.89; 95% CI, 0.81-0.98; P =.02).
There were no statistically significant correlations between either baseline MBDA scores or change from baseline in MBDA scores and change from baseline Sharp/van der Heijde score (SHS) for radiographic progression (n=11) or change from baseline in bone turnover markers (n=23). However, 5 of the 9 patients (56%) with high MBDA scores did show SHS changes from baseline that were ≥5.
Study investigators concluded that they “have shown, for the first time, that the MBDA score correlated with DAS28 following treatment with the B-cell depleting agent rituximab and that MBDA score reflected the treatment response. Our findings are consistent with previous research in RA patients treated with other DMARDs.”
Roodenrijs NMT, de Hair MJH, Wheater G, et al. The multi-biomarker disease activity score tracks response to rituximab treatment in rheumatoid arthritis patients: a post hoc analysis of three cohort studies. [published online November 20, 2018]. doi:10.1186/s13075-018-1750-5