Comparative effectiveness of etanercept originator and biosimilar for treating rheumatoid arthritis: implications for cost-savings.

Abstract

This study aimed to assess the comparative effectiveness of the etanercept (ETN) originator (Enbrel) and ETN biosimilar SB4 (Brenzys) as first-line treatment in patients with rheumatoid arthritis (RA), while also exploring the potential cost-savings associated with this approach in Australia. Clinical data were obtained from the Optimising Patient outcomes in rheumatoLogy Australian real-world data set. Adult patients with RA who had initiated treatment with the ETN originator or biosimilar as their first-recorded biologic or targeted synthetic disease-modifying antirheumatic drug between 1 April 2017 and 31 December 2020 were included. Treatment persistence was analysed using survival analysis. Cost-savings were estimated based on data reported by the Australian National Prescribing Service MedicineWise. Propensity score matching followed by inverse probability of treatment weighting selected patients taking originator (n = 209) or biosimilar (n = 141) with similar baseline characteristics and eliminated small differences in baseline disease activity. The median time for 50% of the patients to stop treatment was 19.4 months (95% confidence interval [CI], 14.7-36.4 months) for the originator and 22.4 months (95% CI, 15.0-33.1 months) for the biosimilar (P = 0.95). As a result of pricing policies established by the Australian Government, introduction of the ETN biosimilar would have resulted in a cost-savings of over AU$9.5 million for 1 year of treatment for the patients reported in this study. Treatment persistence using either ETN originator or biosimilar was similar. The cost of all brands of ETN markedly reduced upon listing of the ETN biosimilar, resulting in significant savings for the Australian Government.