Dutch Study at EULAR Evaluates Impact of Switch From Originator to Biosimilar Etanercept

A Dutch study of 80 patients with rheumatic diseases who elected to switch from treatment with originator etanercept to biosimilar etanercept found that 80% were willing to switch, and switching did not affect treatment effectiveness during 1 year of follow up. The study by Wieland D. Muskens and colleagues, was presented at the annual European Congress of Rheumatology, held June 13-16, 2018, in Amsterdam. Because the study was a non-mandatory open-label transitioning study, the researchers were also able to investigate the effect of shared decision-making on 1-year retention rates and reason for withdrawal in daily clinical real-world practice.

Of the 69 patients who switched from originator to biosimilar etanercept, 75% were able to continue using biosimilar etanercept treatment. Patients enrolled in the study were diagnosed with either rheumatoid arthritis (RA), axial spondyloarthritis (SpA), or psoriatic arthritis (PsA). They had all used originator etanercept between June 1, 2016, and October 23, 2017, before being notified by mail of the possibility of switching over to biosimilar etanercept. The patients had an opportunity to consult with their rheumatologists about biosimilars and switching to a biosimilar at their next outpatient visit; they were assured that they could switch back to originator etanercept if they encountered difficulties with the biosimilar.

Following the switch, data were collected on disease activity (DA) [Disease Activity Score in 28 joints for RA and PsA and the Ankylosing Spondylitis Disease Activity Score for SpA] as well as medication use and adverse events from the time of the switch until October 23, 2017. Reasons for stopping biosimilars were verified using patients’ hospital health record systems. The researchers also assessed reasons for change in DA and discontinuation of biosimilar treatment.

A total of 69 patients taking originator etanercept elected to switch to the biosimilar after a median time of 5.1 years. By October 23, 2017 (median follow up of 307 days), the mean DA did not significantly differ from the DA at baseline: 3.1 (95% CI, 2.5-3.7) vs 2.8 (95% CI, 2.5-3.1). At the end of follow up, 25% of patients had discontinued their treatment and either switched back to originator etanercept (18%), switched to another biological medication (3%), or stopped treatment with biologicals.

Reasons cited for switching back to the originator were adverse events (58%), lack of effect (17%), and adverse event and lack of effect (25%). Among the patients who switched, only 1 serious adverse event was reported—a drug hypersensitivity reaction.