International – Convergence: Confusion lingers over interchangeability and switching of biosimilars

While there are some areas of general alignment on standards for accepting biosimilar applications in the US, EU and Canada, some differences are impeding global development programs, according to panelists at RAPS Convergence 2023.

The panelists explored some of these similarities and differences against the backdrop of a rapidly evolving biosimilar market.

Leah Cristl, the session’s moderator and executive director of global biosimilar regulatory affairs and R&D policy at Amgen, opened the discussion by highlighting lingering areas of confusion around the terms interchangeability, switching and substitution, which the various regulators define differently.

In the US, pharmaceutical substitution is a practice where one drug can be switched to another in the pharmacy without consulting the prescriber, while switching is when a prescriber decides to exchange a biosimilar for another medicine with the same therapeutic intent. The term interchangeable is defined by statute to mean that the product may be substituted for the reference product without the intervention of the prescriber.

These terms “have created a lot of confusion globally,” Cristl said…