Infliximab Biosimilars Uptake in US Reveals Ongoing Concerns

TOPLINE:

Uptake of infliximab biosimilars rose slowly across private insurance, Medicaid, and Medicare when two were available in the United States during 2016-2020 but increased significantly through 2022 after the third biosimilar became available in July 2020. However, prescriptions in Medicare still lagged behind those in private insurance and Medicaid.

METHODOLOGY:

• Researchers analyzed electronic health records from over 1100 US rheumatologists who participated in a national registry, the Rheumatology Informatics System for Effectiveness (RISE), for all infliximab administrations (bio-originator or biosimilar) to patients older than 18 years from April 2016 to September 2022.
• They conducted an interrupted time series to account for autocorrelation and model the effect of each infliximab biosimilar release (infliximab-dyyb in November 2016, infliximab-abda in July 2017, and infliximab-axxq in July 2020) on uptake across Medicare, Medicaid, and private insurers.

TAKEAWAY:

• The researchers identified 659,988 infliximab administrations for 37,560 unique patients, with 52% on Medicare, 4.8% on Medicaid, and 43% on private insurance.
• Biosimilar uptake rose slowly with average annual increases < 5% from 2016 to June 2020 (Medicare, 3.2%; Medicaid, 5.2%; private insurance, 1.8%).
• After the third biosimilar release in July 2020, the average annual increase reached 13% for Medicaid and 16.4% for private insurance but remained low for Medicare (5.6%).
• By September 2022, biosimilar uptake was higher for Medicaid (43.8%) and private insurance (38.5%) than for Medicare (24%).

IN PRACTICE:

“Our results suggest policymakers may need to do more to allow biosimilars to get a foothold in the market by incentivizing the development and entry of multiple biosimilars, address anticompetitive pricing strategies, and may need to amend Medicare policy to [incentivize] uptake in order to ensure a competitive and sustainable biosimilar market that gradually reduces total drug expenditures and out-of-pocket costs over time,” wrote the authors of the study.

SOURCE:

The study was led by Eric T. Roberts, PhD, University of California San Francisco. It was published online on July 30, 2024, in Arthritis & Rheumatology.

LIMITATIONS:

First, while the biosimilar introductions are likely catalysts for many changes in the market, some changes in slopes may also be attributable to the natural growth of the market over time. Second, this study may neither be generalizable to academic medical centers, which are underrepresented in RISE, nor be generalizable to infliximab prescriptions from other specialties. Third, uptake among privately insured patients changed shortly after November-December 2020, raising the possibility that the delay reflected negotiations between insurance companies and relevant entities regarding formulary coverage.

DISCLOSURES:

This study was funded by grants from the Agency for Healthcare Research and Quality and the National Institute of Arthritis and Musculoskeletal and Skin Diseases. One author disclosed receiving consulting fees from Pfizer, AstraZeneca, and Bristol Myers Squibb and grant funding from AstraZeneca, The Bristol Myers Squibb Foundation, and Aurinia.

This article was created using several editorial tools, including AI, as part of the process. Human editors reviewed this content before publication.