Infliximab biosimilar uptake rapidly increased only after release of a third option
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Key takeaways:
- The availability of just one or two biosimilars for a given drug may not be enough to increase uptake.
- Medicare uptake continued to lag for up to 2 years even after a third biosimilar was available.
Infliximab biosimilar uptake increased by no more than just 5% annually following the release of its first two biosimilars, but then shot up by 13% to 16% for most patients after a third option emerged, according to data.
“Biosimilars hold so much promise to contain costs for patients, but the initial uptake has fallen well short of expectations, which has cost patients and taxpayers hundreds of millions of dollars,” Eric T. Roberts, PhD, a research specialist in the division of rheumatology at the University of California, San Francisco, told Healio.
“The recent increase in uptake of biosimilar infliximab offered us the opportunity to explore how the market was changing across two important market forces — insurance coverage and the number of biosimilars on the market — to understand how to optimize future biosimilar market introductions,” he added.
For that analysis, Roberts and colleagues examined electronic health data from the Rheumatology Informative System for Effectiveness (RISE) registry, which covers a third of U.S. rheumatology practices. The analysis included all administrations to adult patients from April 2016 to September 2022 of either originator infliximab (Remicade, Janssen) or one of its three biosimilars, Inflectra (infliximab-dyyb, Celltrion), released November 2016; Renflexis (infliximab-abda, Samsung Bioepis), released July 2017; and Avsola (infliximab-axxq, Amgen), released July 2020.
The main outcome was the proportion of patients using a biosimilar. To model how each successive biosimilar release impacted uptake across Medicare, Medicaid and private insurers, the researchers employed an interrupted time series with the Prais-Winsten procedure to account for autocorrelation.
From April 2016 to June 2020, when the first two biosimilars were being released, the model demonstrated an average annual increase in biosimilar uptake of 5% or less across the board (Medicare, 3.2%; Medicaid, 5.2%; private insurance, 1.8%), according to the researchers, who published their findings in Arthritis & Rheumatology.
Then, after the third biosimilar release in July 2020, the increase rose by 13% annually for Medicaid patients, and by 16.4% annually among those with private insurance. However, annual increases for patients using Medicare remained low at 5.6%.
By September 2022, uptake rates were 43.8% for Medicaid, 38.5% for private insurance and 24% for Medicare.
According to Roberts, research team was surprised by “how responsive the private insurance market appeared,” noting its “sharp shift in uptake” following the availability of a third biosimilar.
“We hypothesize the increase occurred as cost savings were large enough to overcome anticompetitive policies pharmaceutical companies use to maintain market share, like offering rebates for multiple products in exchange for coverage restrictions,” he said. “This suggests that future biosimilar rollouts could be more successful by implementing policy to encourage the market introduction of multiple biosimilars and/or implementing rules to prevent anticompetitive pricing strategies.
“Rheumatologists are navigating a turbulent biosimilar marketplace and having to balance everything from patient preferences to paperwork associated with switching, to monitoring revenue from infusions, to formulary changes designed by pharmacy benefit managers,” Roberts added. “Clinicians should advocate for transparent and fair biosimilar policies that reduce costs as well as administrative and financial burdens on practices.”
For more information:
Eric T. Roberts, PhD, can be reached at eric.roberts@ucsf.edu.
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