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Report: FDA Final Guidance on Biosimilar Interchangeable Status

May 14, 2019

This past week, the US Food and Drug Administration (FDA) finalized their guidance on how biosimilars can achieve interchangeable status.

Currently, no interchangeable biosimilars have been approved in the US. However, there is at least one known study underway to assess interchangeability for an approved biosimilar. With more interchangeable products likely coming to the US in the coming years, a final interchangeable guidance provides further direction on how to develop interchangeable products.

Changes in the final guidance were numerous. The final document is seven pages shorter than the draft and does not include two appendices on comparative-use human factors studies that were originally included in the draft.

During the open comment period, multiple terms were called into question as lacking clarity, including “residual uncertainty” and “fingerprint-like,” the latter of which was used in the draft to describe the similarity between the proposed interchangeable product and the reference product. However, the final guidance excludes any mention of “fingerprint-like” and includes only one mention of “residual uncertainty.”

“The agency also considered the numerous comments on the draft interchangeability guidance and made changes to provide increased clarity to stakeholders,” said Norman E Sharpless, MD, acting commissioner, FDA, in a press release (May 10, 2019).

Other commenters took issue with the requirement that US-licensed reference products must be used in a switching study. The FDA has altered this requirement in the final guidance and renamed the corresponding section.

The requirement that companies use “switching studies” to determine whether alternating between a biosimilar and the reference product impacts the safety or efficacy of the treatment remains in the final guidance.

In advancing the broader policy efforts for biosimilar and interchangeable products, soon we will also be issuing additional guidance on the agency’s recommendations on the design and evaluation of comparative analytical studies and other important scientific considerations needed to support a demonstration that a biological product is biosimilar to a reference product,” Dr Sharpless stated. “This data will help build the foundation for a development program for a proposed biosimilar or interchangeable product.”—Zachary Bessette

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