The nonprofit industry group Biosimilars Forum is calling on the US Food and Drug Administration (FDA) to clarify that a demonstration of interchangeability represents a distinct requirement for additional data compared to a demonstration of biosimilarity.

The comment, released this week, follows FDA's issuance of draft guidance on biosimilar interchangeability in January and the release of other comments from stakeholders last month, who also sought more clarity from FDA.

Up front, the Forum notes the importance "for stakeholders across the health care industry to understand that the FDA does not have more than one standard of product quality for the approval of biologics and that the safety and efficacy profiles of biosimilars and their corresponding interchangeable biologics are the same."

In addition, the group representing biosimilar developers including Amgen, Pfizer, Teva and others, also points to several terms that appear in the draft guidance that have not been well-defined, such as "switching" and "substitution."

"The Forum believes industry and the public would benefit from the adoption of a glossary to define particular terms related to interchangeability that would supplement the definitions provided in the recently finalized FDA Guidance to Industry: Clinical Pharmacology Data to Support a Demonstration of Biosimilarity to a Reference Product," the comment says.

The Forum also calls on FDA to clarify the difference between physician-initiated switching and independent pharmacy-level substitution, which "has been the source of significant confusion that could hinder the uptake of biosimilars in the marketplace."

The comment also focuses on the data needed to support an interchangeability finding as outlined in the draft, and specific questions from FDA.

Biosimilars Forum Comment