The US Food and Drug Administration (FDA) has issued a new draft guidance document on biosimilars intended to assist sponsors with the design and use of clinical pharmacology studies to support a decision that a proposed therapeutic biological product is biosimilar to its reference product.
The guidance pertains to products for which pharmacokinetic (PK) and pharmacodynamics (PD) are required to help demonstrate biosimilarity. The agency focuses on how manufacturer can demonstrate biosimilarity through clinical pharmacology. The guidance is one of many under development by the agency to establish a comprehensive biosimilar pathway.
The FDA defines biosimilarity as being “highly similar to the reference product notwithstanding minor differences in clinically inactive components and that there are no clinically meaningfully differences between the biological product and the reference product in terms of the safety, purity and potency of the product.”
The guidance provided a description of four categories of similarity between a treatment under review and the approved biologic. The four categories of similarity include not similar, similar, highly similar and highly similar with fingerprint-like similarity. The degree of similarity will determine the extent to which further study is required. For those considered not similar, the agency would not recommend further development through the regulatory pathway unless modifications to the manufacturing process were made. If a product was considered highly similar with fingerprint-like similarity, the biosimilar developer would need only targeted animal or human studies to resolve residual uncertainty and support biosimilarity.
The description of how the levels of similarity affect the amount of additional data that will be required by the FDA also underscored the stepwise approach that makers of biosimilar products are expected to take. The stepwise approach requires drugmakers to research, identify outstanding areas of uncertainty and then modify future research to tie up loose ends.
In 2010, the Patient Protection and Affordable Card Act (PPACA) vested FDA to establish a detailed biosimilar pathway. However the agency has been slow to issue and finalize guidance documents regarding its expectations for biosimilar applications, a process which has been well established in Europe for some time now.
The draft guidance, which is open for industry feedback until August 12, only addresses some of the key issues regarding biosimilars. Key issues such as interchangeability, labeling and naming of biosimilars and finalizing earlier guidance documents still exist.
To view the draft guidelines, click here.
Source: US Food and Drug Administration
Last updated: 5/14/14; 4:10pm EST