The Food and Drug Administration yesterday issued draft guidance on how it intends to name new and previously licensed nonproprietary biological products, commonly referred to as biosimilar products. “FDA’s current thinking is that shared nonproprietary names are not appropriate for all biological products,” the guidance states. “There is a need to clearly identify biological products to improve pharmacovigilance, and, for the purposes of safe use, to clearly differentiate among biological products that have not been determined to be interchangeable. Accordingly, for all biological products, FDA intends to designate a nonproprietary name that includes a suffix composed of four lowercase letters. Each suffix will be incorporated in the nonproprietary name of the product.” The agency requests comments on the draft guidance by Oct. 27, including whether the nonproprietary name for an interchangeable product should include a unique suffix or share the same suffix as its reference product. FDA also issued a proposed rule for naming six particular biological products.