AMCP Nexus Features Reports on Patterns of Biosimilar and Follow-on Use in the United States

This week, during the Academy of Managed Care Pharmacy Nexus 2019 meeting, held in National Harbor, Maryland, healthcare practitioners have gathered to share insights into patient care. Among the groups presenting new findings are 2 research teams that have investigated patterns of use for biosimilar and follow-on products in the United States, and their findings provide insight into how biosimilars are progressing in the US market.

New Users of Biosimilar G-CSF Have Increased Over Time

First, researchers from the Biologics and Biosimilars Collective Intelligence Consortium, an organization that addresses real-world evidence on biologics and biosimilars, reported on their study that evaluated characteristics and patterns of product use in patients who were treated with granulocyte colony-stimulating factor therapies.¹

The present investigation, part of a larger, real-world observational comparative effectiveness research study, assessed adults who received any G-CSF agent, between 2012 and 2018, to prevent or treat febrile neutropenia.

From among 36 million health plan members, representing more than 81 million person-years of data, the researchers identified 29,992 incident users of reference filgrastim (Neupogen), 4686 incident users of follow-on filgrastim (tbo-filgrastim), and 4743 incident users of biosimilar filgrastim (Zarxio). Patients across the 3 groups were similar in terms of age and sex.

The total use of all filgrastim products was consistent at about 6900 users each year, but by 2017, incident use of the reference filgrastim declined to less than 45%, while use of the biosimilar increased to 35.7%, and use of follow-on filgrastim increased to 19.5%. Those increases for the biosimilar and follow-on amounted to a change from just 40 users of the biosimilar in 2015 to 2387 users in 2017, and 644 users of the follow-on in 2014 to 1298 users in 2017.

Among patients who used the biosimilar, 11.4% had a history of using the reference filgrastim. Among those who used the reference, 0.85% had previously used the biosimilar.

This longitudinal surveillance, say the authors, shows that new users of the biosimilar and follow-on increased over time, while overall numbers of new users of G-CSFs stayed relatively flat.

Inflation Rebates May Have an Impact on Follow-on, Generic Market Share

Policies including statutory rebates or statewide preferred drug lists (PDLs) can impact the use of biosimilars, follow-ons, and generic drugs in Medicaid fee-for-service (FFS) and managed care organizations (MCOs), particularly with respect to drugs that have high price increases that have large inflation rebates.

Researchers from the University of Pittsburgh compared the use of 2 subsequent-entry drugs across states that had only FFS Medicaid, those that had MCOs that were not subject to statewide PDLs, and states with MSOs that had statewide PDLs.²

They used 2018 Medicaid drug utilization data to assess records for the first 3 quarters of 2018 for all insulin glargine and glatiramer products. They then calculated the market share of follow-on insulin glargine (Basaglar) and generic glatiramer. Finally, they compared the products’ market shares across the 3 state groups.

The researchers found that the market shares of the follow-on insulin glargine and generic glatiramer were higher in MCOs (60.5%, 59.4%) than in FFS (3.7%, 5.7%) for the follow-on insulin and generic glatiramer, respectively (P <.001).

Market share for the follow-on and generics were highest in states where there were not statewide PDLs, and lowest in states with only FFS. There was also a significant correlation between state-level MCO penetration and the share of new products, and states where there was higher use of the follow-on insulin also had higher use of the generic glatiramer.

According to the authors, these findings likely reflect the importance of inflation rebates, with are retained by states, not by MCOs.

References

1. Lockhart C, McDermott C, Marshall J, Mendelsohn A, Pawloski P, Brown J. Longitudinal evaluation characteristics, treatment patterns, and healthcare resource utilization among patients using granulocyte colony stimulating factors: a study by the Biologics and Biosimilars Collective Intelligence Consortium. Presented at: the Academy of Managed Care Pharmacy Nexus 2019; October 29 to November 1, 2019; National Harbor, Maryland. Abstract C22.

2. Hernandez I, Gellad W. Use of biosimilar and specialty generic medication in Medicaid: differences between managed care and fee for service. Presented at: the Academy of Managed Care Pharmacy Nexus 2019; October 29 to November 1, 2019; National Harbor, Maryland. Abstract U1.