Last week, the Food and Drug Administration (FDA) announced that it has published a list of licensed biological products and interchangeable biosimilars to be known as the Purple Book. The Purple Book is meant to be the biological equivalent of the pharmaceutical “Orange Book,” which is used by government agencies and healthcare providers to identify which drug products can be substituted for another. The Orange Book contains all pharmaceutical drug products that are approved or have not been withdrawn for reasons of safety or efficacy, with the exception of products marketed before the Federal Food, Drug and Cosmetic Act or products approved solely on the basis of their safety.

The Purple Book is separated into two parts. The first section lists products approved by the Center for Drug Evaluation and Research (CDER), while the second section lists products approved by the Center for Biologics Evaluation and Research (CBER). Each product listing in the Purple Book includes the biologic license application (BLA) number, nonproprietary product name, brand name, date of licensure, date of first licensure and expiration date of reference drug, and certain exclusivity information. The listing summary also specifies whether a product has been withdrawn. In the future, the listings in the Purple Book will expand to include approved biosimilars and interchangeables for each referenced biologic.

Much like the Orange Book, the Purple Book is intended to aid government agencies and healthcare providers trying to identify which biological products are interchangeable. However, the Purple Book and Orange Book have a few key differences. Unlike the Orange Book, the Purple Book includes no patent information and, due to the lack of of biosimilar products currently on the market, is relatively sparse for now. Additionally, the FDA has not yet confirmed whether the Purple Book will maintain a range of “interchangeable” rankings, similar to how the FDA grades drugs in the Orange Book.

Going forward, both healthcare providers (including pharmacies and prescribers) and manufacturers will need to keep a close eye on this new list. In addition to the various state laws that providers will need to monitor, the Purple Book will provide clear insight on interchangeability and substitutability of biologic products. Manufacturers also will need to monitor the list for exclusivity and possible generic opportunities. In the near future, the Purple Book, similar to the Orange Book, could have a dramatic effect on prescribing and manufacturing practices.