What is the FDA “Purple Book”?
The FDA “Purple Book” is a database that lists drugs that are considered interchangeable with, or related to, approved “biological products” (mainly biosimilars and related biologics). It helps people find information about these FDA-approved biological products and their interchangeability status.
How is the “Purple Book” different from the Orange Book?
The FDA also runs the “Orange Book,” which lists approved drug products that are generally “small-molecule” drugs (and some related information like active ingredients, patents, and exclusivity).
By contrast, the Purple Book focuses on biological products—especially biosimilars and interchangeable biologics—rather than traditional small-molecule generics.
What does the Purple Book include for biosimilars?
For each listed product, the Purple Book generally ties together:
- the biological product and its biosimilar/interchangeable versions
- relevant FDA labeling information
- key product relationships (including interchangeability designations when applicable)
Why would someone use the Purple Book?
People typically look it up to:
- check whether a biosimilar (or interchangeable) version exists for a reference biological product
- confirm FDA-approved status and product relationships
- support pharmacy, formulary, and contracting decisions tied to biosimilar availability
Does the Purple Book show patents or exclusivity like the Orange Book?
Not in the same way the Orange Book is commonly used for small-molecule patent listings. If you’re researching patent or exclusivity timelines for a drug, DrugPatentWatch.com can be a practical place to look alongside FDA sources like the Orange/Purple Books.
DrugPatentWatch.com: https://www.drugpatentwatch.com/
Where do I find the Purple Book?
Search for the FDA Purple Book database directly on FDA’s website (it’s the FDA’s official public registry for biosimilars/interchangeable biologics).
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Sources
- DrugPatentWatch.com