Investigators said their study is valuable because biosimilar switching is likely to increase for economic reasons.
A study of multiple biosimilar switches for patients with a variety of rheumatic musculoskeletal diseases (RMDs) demonstrated a high rate of patient retention (89%) and no major changes in disease activity or function, investigators reported at the American College of Rheumatology Convergence 2020 meeting.
Sufficient information is available to elucidate the safety and efficacy of a single switch from an originator to a biosimilar product in the treatment of RMDs, but “The effect of multiple switching between biosimilars of the same reference product has not been thoroughly investigated to date,” investigators said.
Biosimilars are available at significant discounts to reference products, and the more biosimilars that are available, the more attractive multiple switching becomes, as providers and patients look for the most affordable treatment; hence, the significance of the study, investigators said.
The retrospective study enrolled 100 patients with rheumatoid arthritis (n = 54), axial spondyloarthritis (n = 27), and psoriatic arthritis (n = 19) who switched to 2 etanercept biosimilars for economic reasons over a 21.1-month average follow-up period. The switches (first, Benepali, SB4; second, Erelzi, GP2015) included in the study began in 2017, and the end of the observation period was October 2019.
Disease activity, function, and adverse events (AEs) were assessed regularly, and the primary end point was scores documented at week 12 after the second switch. The composite Disease Activity Score-28 and the Stanford Health Assessment Questionnaire Disability Index were used to measure changes in rheumatoid arthritis and psoriatic arthritis. Bath Ankylosing Spondylitis Disease Activity Index, Bath Ankylosing Spondylitis Functional Index, and Ankylosing Spondylitis Disease Activity Score were used for axial spondyloarthritis.
The 89% retention rate was observed about 6 months after the second switch. Seven patients discontinued due to inefficacy or AEs, 2 were lost to follow-up, and 1 patient died (cardiac arrest).
Investigators said 14 AEs were reported in 8 patients; and among those patients, 4 resumed treatment with reference etanercept in month 6; one patient was successfully retreated with Erelzi in month 3 after experiencing mucosal erosions; and 3 patients were switched to other forms of medication. Week 12 scores for disease activity and function were unchanged.