This past week, the Food and Drug Administration (FDA) announced the creation of the "Purple Book," which will list all biological products, including any biosimilar and interchangeable biological products, licensed by the FDA. Although, the color purple is closely related to the 2014 color of the year, the selection of purple appears to have been mere coincidence. Although the Purple Book is analogous to the well-known "Orange Book" that lists new chemical entities, there are significant differences, such as those discussed below.

What will the Purple Book include?

The Purple Book will include the date a biological product was licensed, whether the FDA has evaluated the product for reference product exclusivity, and whether a product has been determined to be biosimilar to or interchangeable with a reference biological products. The FDA explained on its website that any biosimilar or interchangeability will be listed under the reference product.

How will the Purple Book be used?

According to the FDA, one of the purposes of the Purple Book is to help people determine if a particular biological product has been designated by the FDA to be biosimilar to or interchangeable with a reference biological product. This can be important for doctors when choosing medications and for the filling of prescriptions by pharmacies.

The Purple Book will also help a user to find whether the FDA has determined the statutory exclusivity period for a specific biologic product. This is important because it will lead to the FDA's determination of the reference product's exclusivity expiration date. The expiration date is the date on which the FDA can approve a biosimilar or interchangeable product.

If the Purple Book does not include an expiration date, does the biologic have any exclusivity?

Although, one may have expected the FDA to provide an expiration date for all biologics it has chosen not to. The FDA explained that the absence of an expiration date "does not mean that the biological products on the list are not, or were not, eligible for exclusivity." Instead, the FDA has only made the determination if there is a "regulatory necessity" or the applicant has requested the FDA make such a determination. Therefore, if an expiration date is not listed by the FDA, this does not mean that the product is ineligible for the statutory exclusivity. Rather, it may simply mean that the FDA has not had time or the resources to determine the date.

Where are the patents?

The Purple Book will not list patents for biologic products. This is one of the most significant differences between the Orange Book and the Purple Book. Although a user can search for the relevant patents of an approved new chemical entity listed in the Orange Book, a user will not be able to find the same information about biologics via the Purple Book. This is not terribly surprising, because the framework for biosimilar litigation is significantly different than the traditional ANDA litigation. According to recent news reports, the FDA has no plans to include patent information.

How do I search the Purple Book?

While the FDA has a website to search the Orange Book, no equivalent search mechanism exists for the Purple Book. Instead, the FDA has provided two lists of biologics, depending upon which department of the FDA has approved the product. The lists can be found here. The FDA states that the lists will be updated "periodically."

The Purple Book is a significant step for the FDA. The FDA has recently accepted its first biosimilar application. The Purple Book will enable users to track approval of biosimilars and interchangeables, as well as when a product may be approved. However, because the Purple Book does not include any patent information, it will not provide all of the information when a competitor will or could enter the market.

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