On Tuesday, February 21st, the FDA’s Center for Drug Evaluation and Research (CDER) announced the availability of an updated version of the Purple Book.
What is the Purple Book?
“The ‘Purple Book’ lists biological products, including any biosimilar and interchangeable biological products, licensed by FDA under the Public Health Service Act (the PHS Act).” The FDA developed these lists to serve as a resource to help users find out if the Agency has determined a biological product to be biosimilar to or interchangeable with a reference biological product.
There are separate lists for biological products regulated by CDER and those regulated by the Center for Biologics Evaluation and Research (CBER).
What information does the Purple Book include?
For products licensed under section 351(a) of the PHS Act, the Purple Book lists provide the following information:
- Date the biological product was licensed by FDA.
- Whether a biological product licensed under section 351(k) of the PHS Act has been determined to be biosimilar to or interchangeable with an already-licensed FDA biological product.
- Whether FDA evaluated the biological product for reference product exclusivity under section 351(k)(7) of the PHS Act.
However, FDA states that “the list will not identify periods of orphan exclusivity and their expiration dates for biological products as those dates are available at the searchable database for Orphan Designated and/or Approved Products.”
What is a reference product, biosimilar, and interchangeable product?
Section 351(i)(4) of the PHS Act states that “a ‘reference product’ is the single biological product licensed by FDA under section 351(a) of the PHS Act against which a proposed biological product is evaluated in an application submitted under section 351(k).”
Biosimilar or biosimilarity means that, aside from minor differences in clinically inactive components, the biological product in question is extremely similar to the reference product. Additionally, for a product to be considered biosimilar there must be no “clinically meaningful differences between the biological product and the reference product in terms of safety, purity and potency of the product.” (Section 351(i)(2) of the PHS Act)
“An ‘interchangeable’ biological product is a product that has been shown to be biosimilar to the reference product, and can be expected to produce the same clinical result as the reference product in any given patient.” Furthermore, the risks of using the biological product must not be greater than the risks of using the reference product.
Updating the Purple Book
As resources permit, FDA states that the Purple Book will be updated as new biological products are licensed by FDA under section 351(a) or 351(k) of the PHS Act, and/or as it “makes a determination regarding date of first licensure for a biological product licensed under section 351(a) of the PHS Act.”