Real-world data from the prospective, observational COMPANION-B study showed that the biosimilar SB4 had similar efficacy over 12 months compared with etanercept reference in patients with well-controlled rheumatoid arthritis with stable disease.
The prospective, real-world, observational COMPANION-B study was designed to evaluate the effectiveness of switching to the etanercept biosimilar SB4 from etanercept reference compared with continued etanercept treatment in patients with stable rheumatoid arthritis (RA) and low disease activity or those who were in remission. Full planned analyses of the study were not conducted because of insufficient enrollment; only descriptive analyses were done, and were presented at the American College of Rheumatology (ACR) Convergence 2020 meeting.
The study was conducted in 14 sites in Canada and 5 sites in Australia. Study criteria included patients aged ≥18 years with diagnosis of RA by 2010 ACR criteria, who received treatment with etanercept as their first or second biologic for ≥6 months and had stable disease (defined by Disease Activity Score in 28 joints with erythrocyte sedimentation rate [DAS28-ESR] <3.2 at enrollment with no evidence of flare within the previous 3 months). The primary study end point was disease worsening at 12 months, which was defined as a composite of occurrence of an increase from baseline of DAS28-ESR (≥1.2 increase from baseline and minimum score ≥3.2), increase in dose/frequency of treatment because of disease worsening, or discontinuation of SB4 or etanercept as a result of disease worsening.
A total of 163 patients were enrolled in the study; of these, 109 patients continued to receive etanercept and 54 patients switched to SB4. The mean age of patients in the etanercept cohort was 60.4 years (standard deviation [SD], 12.7) and 61.1 years (SD, 13.6) for the SB4 cohort; the majority of patients in both groups were female (66.7%) and Caucasian (90%). The duration of RA, disease activity scores, and other clinical characteristics were similar in the 2 groups. At baseline, the mean duration of RA in the etanercept group was 17.2 years (SD, 10.4) and 18.6 years (SD, 10.8) in the SB4 group; RA disease activity was similar for both groups.
Overall, 83.5% of patients in the etanercept group and 75.9% of patients in the SB4 group completed the study; 94.1% of patients in the etanercept group and 84.3% of patients in the SB4 group received ≥36 weeks of study treatment. At month 12, RA disease activity was similar between groups using the following assessments: DAS28-ESR, Clinical Disease Activity Index, Health Assessment Questionnaire Disability Index score, tender joint count, swollen joint count, patient global assessment, and physician global assessment. The incidence of adverse events was low and similar between groups. The proportion of patients with disease worsening at month 12 was similar between groups: 17.6% (95% confidence interval [CI], 8.4%-30.9%) for patients in the SB4 group and 22.8% (95% CI, 15.5%-32.2%) for patients in the etanercept group.
Based on the results of the prospective, observational COMPANION-B study, it was concluded that the biosimilar SB4 demonstrated similar efficacy over 12 months compared with etanercept reference in patients with well-controlled RA with stable disease in a real-world setting.
Pope J, et al. Arthritis Rheumatol. 2020;72(suppl 10):Abstract 822.