A Biosimilar Hierarchy

It’s not only “biosimilar” or “interchangeable” any more.

The FDA (per a report in BioCentury) 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product will depend on the agency's confidence in the level of similarity to the reference product, according to draft guidance published Tuesday.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.

Obvious implications here for the naming debate.

Analytical studies and at least one clinical pharmacokinetic study intended to support a demonstration of biosimilarity must include an adequate comparison of the product directly with a U.S. licensed reference product. According to the draft, a sponsor may use a non-U.S. licensed comparator product in certain studies to support this comparison. The sponsor must provide adequate data to establish "an acceptable bridge" between the non-U.S. licensed comparator product and the U.S. licensed reference product.