Study Compares Cost, Effectiveness of Etanercept Biosimilar, Originator for Rheumatoid Arthritis

Claire Deakin, PhD

Credit: University of New South Wales

Results from a recent study comparing the effectiveness of etanercept originator and biosimilar SB4 as first-line treatment in patients with rheumatoid arthritis are providing real-world evidence of similarity between the treatments.

Using data from more than 300 adult patients with rheumatoid arthritis from the OPAL Australian real-world data set, investigators found similar rates of treatment persistence between those taking originator and biosimilar, further noting significant cost-savings for the Australian government as a result of reference pricing.¹

“SB4 has a similar structure and pharmacokinetic profile in male patients to the originator. In a phase III randomised trial, the drugs had equivalent rates of American College of Rheumatology 20% response at 24 weeks in patients with severe to moderate RA, and comparable efficacy and safety at week 52,” wrote investigators.¹ “Since randomised trials are conducted in specific patient populations in specialised environments that may not be generalizable to routine clinical practice, real-world evidence studies have a valuable and complementary role.”

Biologic treatments are often associated with costs that make them unattainable for many patients. Biosimilars mimic the active ingredient in the reference biologic and are equally as safe and effective at a fraction of the price. Further insight into the real-world safety, efficacy, and cost savings associated with biosimilars can better inform their impact on patients’ health and treatment persistence.²

To assess the comparative persistence of the etanercept originator and biosimilar SB4 for the treatment of patients with rheumatoid arthritis while also considering the potential cost-saving implications, Claire Deakin, PhD, of the School of Population Health at the University of New South Wales, and colleagues collected and examined clinical data from the OPAL Australian real-world data set. It is drawn directly from clinical data entered into a customized EMR during routine clinical care by 112 rheumatologists from 43 clinics across Australia. At the time of this study, 210,271 patients were included in the data set.¹

For inclusion in the present study, patients were required to have a recorded diagnosis of rheumatoid arthritis, be older than 18 years of age but younger than 95 years of age at baseline, have initiated treatment with the etanercept originator or biosimilar as their first-recorded biologic disease-modifying antirheumatic drug (DMARD) or targeted synthetic DMARD between April 1, 2017, and December 31, 2020, and had at least 3 months of follow-up. In total, investigators identified 1153 eligible patients, of whom 386 had at least 3 months of follow-up recorded.¹

Investigators performed propensity score matching to increase the similarity of the baseline demographic and clinical features between the originator and biosimilar treatment groups. A total of 350 patients were matched using sex, age, disease duration, swollen 28-joint count, and concomitant medication as input variables. The cohort included 209 patients treated using the etanercept originator and 141 who were treated using the etanercept biosimilar. Of note, matching also eliminated small differences in baseline disease activity between the groups.¹

Treatment persistence was analyzed as an endpoint representing efficacy and tolerability using survival analysis, with treatment stop considered the event of interest. Investigators additionally estimated cost savings based on data reported by the Australian National Prescribing Service MedicineWise.¹

Upon analysis, the median time for 50% of matched patients to stop treatment was 19.4 (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, with no difference observed between the treatment groups in the probability of stopping treatment at any time point during follow up (P = .95). Within the total eligible population (n = 1153), an adverse reaction was the reason for discontinuing treatment in 25 patients (10.1% of recorded reasons for discontinuation) taking the originator and 17 patients (14.5% of recorded reasons for discontinuation) taking the biosimilar.¹

The Australian National Prescribing Service MedicineWise reported the listing of the etanercept biosimilar triggered a 40% price reduction, resulting in a price of about AU$960 for both the originator and biosimilar because of reference pricing policies. For the eligible patient population in the present study, assuming a standard dose of 50 mg of etanercept once a week, investigators noted the estimated cost of treatment for 1 year would have saved the Australian government more than AU$9.5 million.¹

“Our analysis using a large national real-world data set showed similar treatment persistence between the originator and biosimilar groups and supports the ongoing use of ETN biosimilar SB4, as highly similar to the ETN originator,” concluded investigators.¹

References:

1. Deakin CT, Littlejohn GO, Griffiths H, et al. Comparative effectiveness of etanercept originator and biosimilar for treating rheumatoid arthritis: implications for cost-savings. Internal Medicine Journal. https://doi.org/10.1111/imj.16296
2. Pfizer. What Are Biosimilars and How Do They Expand Treatment Options for Patients? September 28, 2022. Accessed December 4, 2023. https://www.pfizer.com/news/articles/what_are_biosimilars_and_how_do_they_expand_treatment_options_for_patients