Assessing the safety and comparative effectiveness of follow-on biologics (biosimilars) in the United States.

As Congress begins drafting legislation concerning the US Food and Drug Administration (FDA) regulation of biosimilars, it is critical to keep in mind that these agents may differ from their innovator compounds. Therefore, it is of the utmost importance to be able to differentiate among innovators and biosimilars in administrative data in order to facilitate the conduct of population-based safety and comparative effectiveness studies. This Commentary proposes methods that would allow these agents to be distinguished in such data.