Practice-level policies ‘likely key drivers’ of infliximab biosimilar uptake
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WASHINGTON — Biosimilar infliximab use is significantly more common among new users vs. those who started with the originator, and particularly less likely among Medicare beneficiaries, according to data presented at ACR Convergence 2024.
The study also found significant variation in biosimilar uptake and switching at the practice level, indicating that “local switching policies are likely key drivers,” the researchers wrote.
“The failure of biosimilars to penetrate the market, reduce the price of biologics and improve patient access has left U.S. policymakers, payers, rheumatologists and the public frustrated,” Eric T. Roberts, PhD, a research specialist in the division of rheumatology at the University of California, San Francisco, told Healio. “There are many reasons behind the slow uptake of biosimilars — legal impediments, economic concerns for patients and clinicians, and safety and administrative concerns for rheumatology practices.
To better understand how these various barriers may be hindering biosimilar uptake, Roberts and colleagues analyzed the use of biosimilar forms of infliximab (Remicade, Janssen) among 37,560 adults included in RISE, a national rheumatology registry, from April 2016 to September 2022.
The researchers examined the effects of insurance and initiation year on starting a new biosimilar using generalized estimating equations. Variation at the practice level was analyzed using the intraclass correlation coefficient.
According to the researchers, 21.8% of infliximab users received a biosimilar during the study period, with 21.6% of new starts initiating with a biosimilar. Among bio-originator users, 11.6% switched to a biosimilar, with a lower switch rate among Medicare beneficiaries (7%) vs. Medicaid (14.2%) and private insurance (16.9%).
The strongest predictors of biosimilar infliximab use were insurance type and the year the patient entered the study. Compared with Medicare, odds of biosimilar use were stronger with Medicaid (OR = 1.62; 95% CI, 1.14-2.29) or private insurance (OR = 1.36; 95% CI, 1.08-1.73). Meanwhile, compared with patients who entered the study in 2016, biosimilar use was more likely among those who entered in 2017 (OR = 1.46; 95% CI, 1.08-1.97), and even more likely for those who entered in 2022 (OR = 5.75; 95% CI, 4.66-7.08).
According to Roberts, the “biggest surprise” in the data was the impact of practice setting on biosimilar uptake. Differences at the practice level accounted for 37% of the variation in new biosimilar starts, and 34% of the variation in biosimilar switches, the researchers wrote.
“There were some practices with very high levels of uptake before the general overall trend to increased use occurred,” Roberts said. “It would be really interesting to understand how these practices overcame barriers that other practices may be facing.”
The results suggest that biosimilar uptake may be held back by a variety of factors, including “reimbursement rates, particularly for Medicare patients; lingering concerns of clinicians regarding the safety and effectiveness of switching patients from bio-originator to a biosimilar; and potentially administrative barriers at practices,” Roberts said.
“Future studies should report the effectiveness and safety of biosimilars from real-world datasets, particularly in patients switching to a biosimilar,” he added. “This would reassure clinicians that these products are appropriate for all their patients. Additional research could interview practices with high levels of biosimilar uptake to understand how these practices have overcome barriers to use.”
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Roberts E. Abstract #2609. Presented at: ACR Convergence 2024; Nov. 14-19, 2024; Washington, D.C.
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