Purple Book exclusivities for biologics

A biosimilar's approval may not take effect until 12 years after the reference product was first licensed, and a biosimilar application may not be submitted until four years after first licensure (42 USC 262(k)(7)(A), (B)). The statute says these periods do not apply to some later licences, such as a supplement, or certain later applications by the same sponsor or a related entity (42 USC 262(k)(7)(C)).

Pediatric studies completed under a written request add six months: four years become four and a half, 12 become 12 and a half, and the seven-year orphan period becomes seven and a half, unless the determination comes later than nine months before the period ends (42 USC 262(m)(2) to (4)).

Once a biological product has been approved as interchangeable with a reference product, FDA does not make approval of a later product as interchangeable with that reference product effective until the earliest of the dates the statute sets: one year after the first interchangeable's first commercial marketing; 18 months after a final court decision on all patents in suit against its applicant, or after dismissal of that action; or, counted from the first interchangeable's approval, 42 months if its applicant has been sued and the litigation is still ongoing, or 18 months if it has not been sued (42 USC 262(k)(6)).

For seven years from approval of a designated orphan drug, FDA does not approve another sponsor's application for the same drug for the same use or indication, with exceptions the regulation lists (21 CFR 316.31(a)).

The download carries four dated exclusivity columns, each read as FDA labels it: Exclusivity Expiration Date, Ref. Product Exclusivity Exp. Date, First Interchangeable Exclusivity Exp. Date and Orphan Exclusivity Exp. Date.

FDA's FAQ describes the reference product exclusivity date as the date the 12-year period ends, including any pediatric extension, and the orphan exclusivity date as the end of the seven-year period, including any applicable pediatric extension. The app shows FDA's dates and never adds six months to them.

FDA has not made a first-licensure determination for every product licensed under 351(a). FDA's FAQ says a missing first-licensure date does not mean the product is not, or was not, eligible for reference product exclusivity under 351(k)(7), and that a missing first interchangeable exclusivity date does not mean the product is not eligible; "Date TBD" means FDA has found the product eligible but has not determined the period.

The Purple Book also publishes the patent lists reference product sponsors provide, within 30 days of providing them to a biosimilar applicant. The capture holds few of these, so the app says when a biologic has no patents in the store.