FDA sets hierarchy of biosimilarity

FDA said the extent of data requirements for a biosimilar product will depend on the agency's confidence in the level of similarity to the reference product, according to draft guidance published Tuesday. Based on comparative analytical data, FDA will characterize its assessment of biosimilarity into one of four levels -- not similar, similar, highly similar or highly similar with a fingerprint-like similarity -- depending on the type, nature and extent of any structural and functional differences revealed.

Additional pharmacologic studies would be required to show that the identified difference is "within an acceptable range to consider the proposed biosimilar product to be highly similar to the reference product." FDA said only products in the top two tiers would meet the statutory requirement for analytical similarity under the Biologics Price Competition and Innovation Act of 2009. Products in the top two tiers would then only require "targeted and selective animal and/or clinical studies to resolve residual uncertainties" to demonstrate biosimilarity. In addition, these data could be used to extrapolate clinical data for additional indications. ...