Why Purple? The “Purple Book” is an easy-to-remember nickname for the “Lists of Licensed Biological Products with Reference Product Exclusivity and Biosimilarity or Interchangeability Evaluations.” Using a color for the nickname of the list draws upon FDA’s (Food and Drug Administration) long-held practice of using “The Orange Book” to refer to “Approved Drug Products with Therapeutic Equivalence Evaluations,” the Agency’s reference listing of all drugs approved under the Federal Food, Drug and Cosmetic Act. Over the years, health care professionals and other stakeholders have come to use the term “Orange Book” in place of this longer, official title. FDA wanted a similarly user-friendly term for a reference listing biologics, biosimilars, and interchangeable products. During a meeting, a staff member said, “how about purple?” Ever since, it is called 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 lists include the date a biological product was licensed under 351(a) of the PHS Act and whether FDA evaluated the biological product for reference product exclusivity under section 351(k)(7) of the PHS Act. The Purple Book will also enable a user to see whether a biological product licensed under section 351(k) of the PHS Act has been determined by FDA to be biosimilar to or interchangeable with a reference biological product (an already-licensed FDA biological product). Biosimilar and interchangeable biological products licensed under section 351(k) of the PHS Act will be listed under the reference product to which biosimilarity or interchangeability was demonstrated.
For products licensed under section 351(a) of the PHS Act, the lists identify the date the biological product was licensed and whether FDA evaluated the biological product for reference product exclusivity under section 351(k)(7) of the PHS Act. If FDA has determined that a biological product is protected by a period of reference product exclusivity, the list will identify the date of first licensure and the date that reference product exclusivity (including any attached pediatric exclusivity) will expire.