AB1171 Effects of successive switches of two different biosimilars of etanercept on outcomes in inflammatory rheumatic diseases in daily practice

Background: A single switch from an originator to a biosimilar product has been shown to be safe and effective in the treatment of rheumatic musculoskeletal diseases (RMDs). The availability of biosimilars has created a financial incentive to encourage switching to cheaper products (“non-medical switch”). This is naturally associated with multiple switches. However, the effect of multiple switching between biosimilars of the same reference product has not been thoroughly investigated to date. Objectives: To assess the effectiveness and safety of systematic non-medical switching from innovator etanercept (ETN) to biosimilar ETN (SB4) and successive to another biosimilar ETN (GP2015) in adult patients with rheumatoid arthritis (RA), psoriatic arthritis (PsA) or axial spondyloarthritis (axSpA) in a real-life setting. Methods: This retrospective study was performed in a tertiary center in adult patients with RA, PsA or axSpA who had been treated with the innovator ETN and who had been switched to two ETN biosimilars for economic reasons thereafter. The first switch from innovator ETN to the first biosimilar ETN occurred between February-May 2017 and the second switch from the first to the second biosimilar ETN occurred between September-December 2017. The end of the observation period was October 2019. Disease activity, function and adverse events (AE) were regularly assessed, and any changes in outcome were recorded during the follow-up period. The scores documented at week 12 week after the second switch were taken as primary outcome. A total of 100 patients (54 RA, 27 axSpA, 19 PsA, mean age 54.3±15.1, 46% male) who switched twice to those ETN biosimilars over a follow-up period of 21.1±7.4 months were included. The retention rate after the second ETN biosimilar switch was 89% about 6 months after the second switch. While 2 patients were lost to follow-up and 1 patient died (cardiac arrest), 7 patients discontinued due to inefficacy or AE, including one pancreatic cancer. One patient was withdrawn due to pregnancy. Overall, 14 AEs were reported in 8 patients. Among them, 4 patients switched back to originator etanercept in month 6, 1 patient re-administered GP2015 successfully in month 3 after suffering from mucosal erosions and in 3 patients another mode of action was prescribed. The scores at week 12 of both, disease activity and function, remained unchanged (Table 1). Table 1. Patient characteristics Assessment Baseline (n=100) SB4 Follow-up 12 weeks (n=100) SB 4 Follow-up 24 weeks (n=100) Second switch to GP2015 (n=100) GP2015 Follow-up 12 weeks (n=97) GP2015 Follow-up 24 weeks (n=89) RA DAS28 3,0 (1,2) 2,9 (1,4) 3,1 (1,2) 2,8 (1,4) 3,4 (2,5) 3,0 (1,4) HAQ 1,4 (0,8) 1,6 (0,9) 1,0 (0,9) 1,5 (0,8) 1,5 (0,8) 1,6 (0,9) PsA DAS28 3,8 (1,4) 1,9 (1,4) 2,8 (1,5) 3,1 (1,1) 4,5 (2,6) 3,6 (2,6) HAQ 1,2 (0,9) 1,0 (0,9) 0,9 (0,9) 1,0 (0,8) 1,0 (0,9) 1,2 (0,8) axSpA BASDAI 5,1 (2,7) 4,5 (2,6) 5,1 (3,8) 4,1 (2,2) 4,6 (2,5) 4,3 (2,4) ASDAS 3,4 (0,8) 2,5 (0,8) 2,7 (0,8) 3,2 (1,8) 2,7 (1,2) 2,5 (0,9) BASFI 4,4 (2,7) 4,3 (2,7) 4,3 (3,2) 4,6 (2,6) 4,5 (2,7) 4,8 (3,0) *Values are mean ± standard deviation Disclosure: Hexal funded this research Conclusion: The retention rate after multiple switches from innovator ETN to two ETN biosimilars was close to 90%. No major changes in disease activity and function were observed in all three indications.