Exploratory analyses of a phase 3 trial comparing infliximab-qbtx to reference infliximab in patients with rheumatoid arthritis (RA) indicate that multibiomarker disease activity score may be used as an assessment of biosimilarity instead of conventional disease activity measures.
To evaluate the utility of the multibiomarker disease activity (MBDA) score as an assessment of biosimilarity, an exploratory analysis of the phase 3 randomized, controlled trial that demonstrated equivalence of the infliximab biosimilar infliximab-qbtx to the reference infliximab sourced from the European Union (infliximab-EU) in patients with active, moderate-to-severe rheumatoid arthritis (RA) was conducted.1 In this exploratory analysis, MBDA scores between treatment groups were compared2; the results of this analysis were reported at the American College of Rheumatology (ACR) Convergence 2020 meeting.
Study inclusion criteria consisted of patients who met the 2010 ACR/European League Against Rheumatism classification criteria for RA and had disease duration of ≥4 months.2 Eligible patients were randomized 1:1 to infliximab-qbtx or infliximab-EU, administered with methotrexate. Mean values of MBDA scores were calculated at baseline and at weeks 6, 14, 30, 54, and 78 by combining the concentrations of 12 serum biomarkers and were categorized as low (1-<30), moderate (30-≤44), and high (>44-100).2
A total of 650 patients were included in the analysis; 236 patients received infliximab-qbtx and 248 patients received infliximab-EU.2 At baseline, mean MBDA scores were similar between patient groups, at 61.3 (standard deviation [SD], ±12.5) for infliximab-qbtx and 58.8 (SD, 13.2) for infliximab-EU; high (>44) MBDA scores were observed at similar frequency in both groups (66.0% and 66.9%, respectively). At all measured time points through week 30, the mean MBDA scores were comparable between infliximab-qbtx and infliximab-EU; the frequency of high MBDA scores (>44) decreased to 42.3% and 40.2%, respectively, at week 30, occurring primarily by week 6 and remaining stable between weeks 6 and 30. No between-group changes were seen in the concentrations of individual biomarkers over time. Changes in MBDA scores from baseline correlated positively with changes from baseline in high-sensitivity C-reactive protein.2
Using MBDA score as an assessment of biosimilarity, the results of the exploratory analysis indicate that changes in MBDA scores over time were similar between the infliximab-qbtx and infliximab-EU groups, which was consistent with previous results obtained using conventional disease activity measures.2 Based on these results, the authors concluded that the MBDA score based on serum protein assessments represents a sensitive assessment of biosimilarity that is independent of conventional disease activity measures based on subjective patient global assessment.2
References
1. Cohen, et al. Arthritis Res Ther. 2018;20:155.
2. Kay J, et al. Arthritis Rheumatol. 2020;72(suppl 10):Abstract 1204.