August 28, 2024

This is part one of a two-part series on biosimilar interchangeability guidance. Follow along for part 2 next week.

In this week’s Behind the Bill, I’d like to dive into a significant shift in the US Food & Drug Administration’s (FDA) approach to biosimilar interchangeability, a move that could reshape the landscape of biological medications in the US.

On June 20, 2024, the FDA issued draft guidance that could dramatically streamline the approval process for interchangeable biosimilars.¹ But first, a brief reminder on what interchangeable biosimilars are; these are biosimilar products that may be substituted for the reference product without prescriber intervention at the pharmacy counter. This is different from standard biosimilars, which are highly similar to an FDA-approved biological product but are not automatically substitutable.²

The Science Behind the Decision

Since the publication of its 2019 Interchangeability Guidance, the FDA has found that approved biosimilars have insignificant risk in terms of safety or diminished efficacy, following single or multiple switches between a reference product and a biosimilar product.¹

Moreover, the FDA notes that currently available analytical technologies can structurally characterize highly purified therapeutic proteins and model in vivo functional effects with a high degree of specificity and sensitivity using in vitro biological and biochemical assays. This technological advancement allows for a more robust and nuanced understanding of biosimilar products, reducing the need for extensive clinical switching studies.¹

New Recommendations for Applicants

The FDA’s draft guidance provides new recommendations for applicants seeking interchangeability status for their biosimilar products¹:

1. Manufacturers can now explain how their existing data on the biosimilar’s structure and performance supports interchangeability. This means they may not need to conduct additional switching studies.
2. Manufacturers should provide information showing that switching between their biosimilar and the reference product is not riskier than using the reference product alone.
3. Manufacturers with pending biosimilar applications can update their submission to seek interchangeability status without necessarily conducting new studies.

These changes aim to make the interchangeability approval process faster and less resource-intensive, potentially bringing more interchangeable biosimilars to market sooner.

Stay tuned for part 2 of this Behind the Bill, where I’ll explore the American College of Rheumatology’s (ACR’s) response, legislative context, and future implications of these changes.

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References

1. US Food and Drug Administration. Considerations in demonstrating interchangeability with a reference product: update guidance for industry. Draft Guidance. June 2024. https://www.fda.gov/media/179456/download

2. US Food and Drug Administration. Biosimilar and interchangeable biologics: more treatment choices. Accessed August 27, 2024. August 17, 2023. https://www.fda.gov/consumers/consumer-updates/biosimilar-and-interchangeable-biologics-more-treatment-choices