When you hear FDA Purple Book, a public database maintained by the U.S. Food and Drug Administration that lists licensed biological products and their interchangeable biosimilars. Also known as Biologics Licensing Database, it’s the go-to reference for anyone trying to understand which biologic drugs have generic-like alternatives approved in the U.S. Unlike the Orange Book, which tracks small-molecule drugs, the Purple Book focuses on complex biological medicines—like insulin, rheumatoid arthritis treatments, and cancer therapies—that can’t be copied exactly but can be closely matched.
Biologics are expensive because they’re made from living cells, not chemicals. That’s why the biosimilars, medications that are highly similar to an already-approved biologic but not identical exist. The FDA Purple Book tells you which ones are approved, which are interchangeable (meaning a pharmacist can swap them without a doctor’s permission), and when the original drug’s exclusivity period ended. This matters because companies developing biosimilars use this list to plan their market entry. If a biologic still has 12 years of exclusivity under the BPCIA, no biosimilar can legally launch yet. But once that clock runs out, the Purple Book becomes the roadmap.
It’s not just for drugmakers. Pharmacists, insurers, and even patients use it to confirm whether a prescribed biologic has a cheaper alternative. For example, if your doctor prescribes Humira, you can check the Purple Book to see if a biosimilar like Cimzia or Amjevita is approved and interchangeable. That’s how you save hundreds—or thousands—of dollars per year. The list also includes authorized generics, brand-name drugs sold under a generic label, made by the same company with the exact same formula, which are different from biosimilars but still part of the broader push for affordable alternatives.
The Purple Book doesn’t list traditional small-molecule generics—that’s the Orange Book’s job. But it does show how the FDA is handling the next wave of drug affordability: biologics. And it’s growing fast. More than 40 biosimilars have been approved since 2015, and the number keeps rising. The FDA updates the list monthly, so it’s always current. If you’re a patient, a pharmacist, or just someone tired of paying $2,000 for a single injection, knowing how to use the Purple Book means you’re not stuck in the dark about your options.
What you’ll find below are real-world stories about how this system works—or doesn’t. From patent tricks that delay biosimilars, to how hospitals choose which biologics to stock, to why some patients still get the brand name even when a cheaper version exists. These aren’t theory pieces. They’re practical deep dives into the rules, loopholes, and real-life impacts of the FDA Purple Book and the drug market it governs.
