Opinions Vary on Biosimilar Naming Conventions

As more biosimilars enter the marketplace, there is disagreement between the FDA and drug manufacturers, as well as among the manufacturers themselves—about naming and distinguishing biosimilars from their reference drug and from each other.

The FDA recently issued a proposal for naming biosimilars that would add a unique (and meaningless) 4-letter suffix to the nonproprietary name of the drug. This move revises the precedent set by the FDA when they approved Sandoz’s Zarxio, a biosimilar of the brand-name drug Neupogen (Amgen) that bears the nonproprietary name filgrastim.

Because at the time there were other biosimilars of filgrastim in the regulatory calendar, the FDA added the suffix “sndz” to the nonproprietary name, resulting in “filgrastim-sndz,” distinguishing the Sandoz biosimilar from that of other manufacturers of filgrastim.

The FDA has now proposed an alternate naming protocol that uses an essentially arbitrary 4-letter suffix. In the case of Sandoz’ filgrastim, the nonproprietary name would change from “filgrastim-sndz” to “filgrastim-jcwp.”

Not unexpectedly, there is controversy among all parties involved in the approval, introduction, and prescribing of biosimilars. Amgen, for example, supports the use of company-based suffixes, although it would change the FDA-configured “amgn” to “amgb.”

As an alternative to any prefix or suffix, several patient and industry groups have endorsed the international naming standards used by the WHO International Nonproprietary Names committee and the US Pharmacopeia.

These standards for multiple products with the same proprietary name use other identifiers such as unique National Drug Codes, unique codified identifiers, and the branded name to distinguish one formulation from the other.