Shortly after approving the first biosimilar under the abbreviated approval pathway created by the Biologics Price Competition and Innovation Act of 2009 ("BPCIA"), the FDA has recently issued 3 final guidances regarding biosimilars.
Biological products, or "biologics," are pharmaceutical products created from biological sources. Unlike chemically synthesized pharmaceuticals, biologics are isolated from natural sources, and are typically more complex than conventional pharmaceutical drugs.
The BPCIA provides abbreviated pathways for the FDA to approve two types of follow-on biologics: biosimilar and interchangeable biological products. Similar to the 1984 Hatch-Waxman Act’s abbreviated pathway for pharmaceuticals, the BPCIA allows a sponsor to seek approval of a "biosimilar" product under section 351(k) of the Public Health Service Act ("PHS Act") by relying on certain existing scientific knowledge about the safety, purity, and potency of the reference product. The BPCIA defines "biosimilar" as (1) "highly similar to the reference product notwithstanding minor differences in clinically inactive components" and (2) having "no clinically meaningful differences between the biosimilar product and the reference biological product in terms of the safety, purity, and potency of the product." To meet the higher standard of "interchangeability," the application must further show (1) the biosimilar is expected to produce the same clinical result as the reference product and (2) a patient can switch back and forth between the biosimilar and the reference product with no adverse effects.
The FDA has been slow to accept and approve biosimilar applications, which has left open questions about how to establish biosimilarity and interchangeability under the statutory definitions. On April 28, 2015, the FDA finalized three draft guidances originally published in 2012:
The new guidances provide insight into the FDA requirements for establishing biosimilarity.
Biosimilars: Questions and Answers Regarding Implementation of the Biologics Price Competition and Innovation Act of 2009
This final guidance addresses three categories of commonly asked questions regarding FDA implementation of the BPCIA: (1) biosimilarity or interchangeability; (2) definitions relevant to the BPCIA; and (3) exclusivity.
With regard to biosimilarity or interchangeability, the guidance states that a proposed biosimilar may have a different formulation, delivery device, or container closure than the reference product under certain circumstances. Additionally, the guidance discloses conditions permitting an applicant to obtain licensure for fewer than all routes of administration, presentations, and conditions of use for which the reference product is licensed. Further, the guidance describes conditions in which a sponsor may support biosimilarity using comparative data with a non-U.S.-licensed product or extrapolated clinical data designed to support a different condition of use. The guidance additionally instructs applicants how to describe the "strength" of a proposed injectable biosimilar. Finally, the guidance states that a biosimilar product that cites a reference product subject to the Pediatric Research Equity Act must include a pediatric assessment unless the applicant initially seeks approval as an interchangeable biological product.
With regard to the BPCIA's definition of "biological product," the guidance discloses the FDA's regulatory definitions of "protein" and "chemically synthesized polypeptide." Additionally, it defines when a proposed biological product is considered to be within the same "product class" as previously approved protein products.
With regard to exclusivity, the guidance instructs applicants and sponsor to search an online database, available here, to identify whether the reference product is subject to unexpired orphan exclusivity. The FDA will not approve a biosimilar during the 7-year exclusivity period.
Scientific Considerations in Demonstrating Biosimilarity to a Reference Product
This final guidance provides an overview of the FDA’s recommendations for establishing biosimilarity and discusses in detail relevant scientific principles for designing data and information to show biosimilarity. The FDA stresses that it will apply a totality-of-the-evidence approach in its assessment of biosimilarity and will use a risk-based approach to evaluate all data and information submitted. The FDA further emphasizes that the information sufficient to demonstrate biosimilarity will be determined on a product-specific basis.
The BPCIA requires an application to include analytical, animal, and clinical studies demonstrating that the biological product is “biosimilar” to a single reference product. As discussed above, the application must establish the product is “highly similar” to the reference product and has “no clinically meaningful differences.” Although the reference product must be U.S.-licensed, the application may rely on data from comparative studies with a non-U.S. licensed comparator product if the data is scientifically relevant. Because the FDA has discretion to determine what data is required to establish biosimilarity in a particular application, it encourages sponsors of the application to meet with the FDA early during product development to discuss adequate scientific justifications.
The FDA encourages sponsors to use a three step approach to develop evidence necessary to establish biosimilarity.