Patient Reported Outcomes for SB5, an adalimumab biosIMILAR, in patients with rheumatoid arthritis and ankylosing spondylitis (PRO-SIMILAR): Study protocol for a phase IV, single-arm, open-label trial

Introduction: Biosimilars are increasing selected as a cost-effective treatment option in the management of immune-mediated inflammatory diseases. Despite equivalent efficacy of biosimilars was demonstrated compared with the originators in randomized controlled trials, biosimilar uptake is often impacted by lack of confidence in these products by the patients. The Patient Reported Outcomes for SB5, an adalimumab biosIMILAR, in patients with rheumatoid arthritis (RA) and ankylosing spondylitis (AS) (PRO-SIMILAR) study was designed to evaluate the efficacy of SB5, from the perspectives of the patients in real world settings. Methods and analysis: PRO-SIMILAR is an ongoing phase IV, single-arm, open-label trial conducted in 35 hospitals across Korea. The study is designed for 1000 adult patients with RA and AS (at least ≥300 in each group) treated in routine clinical practice. Participants are treated with SB-5 40 mg every other week for 52 weeks. The primary efficacy endpoint is European quality of life-5 dimensions-5 level index score at week 52 compared to baseline. The secondary efficacy endpoints are changes in disease activity index scores, proportion of patients achieving remission and clinical response, and rate of SB5 persistence. The safety and exploratory endpoints are include assessments of adverse events, immunogenicity, and pen/syringe preference. Data are collected at baseline, 12, 24 (for RA), 36 (for AS), and 52 weeks.