FDA Releases First-Ever Purple Book for Biosimilar Characterization

The Purple Book, also known as the Lists of Licensed Biological Products with Reference Product Exclusivity and Biosimilarity or Interchangeability Evaluations, made its debut on FDA’s website earlier this month. The book will serve as a therapeutic equivalence guide for biologics and biosimilars and will function much like FDA’s Orange Book for chemical products. The release of the Purple Book comes just weeks after FDA received two applications for approval for Zarzio and Remsima, which were submitted through the 351(k) pathway as biosimilars to Neupogen (filgrastim) and Remicade (infliximab), respectively.

The Purple Book will allow users to review the list of biological products licensed by FDA under the Public Health Service Act. Readers will also be able to see whether a biologic product was licensed under the 351(a) or 351(k) pathway, and which drugs have interchangeability designations.  Although the guide is slated to include, among other things, the product name and proprietary name of each biologic, FDA has not yet provided guidance on whether a biosimilar product should strictly be referred to by its international nonproprietary name or if it will also be identified further with biological qualifiers. FDA did, however, state on its website that biosimilar and interchangeable products will be listed “under the reference product to which biosimilarity or interchangeability was demonstrated.”