As the U.S. Food and Drug Administration mulls plans to review and approve biosimilars in the United States, an argument over the best way to name those medicines is brewing in Washington.

At issue is whether biosimilar versions of biotech therapies should share the same nonproprietary names as branded innovator medicines—as is the case with generic versions of small molecule drugs—or whether they should instead get different names.

Brand-name drugs, such as Lipitor, also have a nonproprietary name, such as “atorvastatin” in Lipitor’s case or “ibuprofen” in the case of Advil.

If biosimilars are allowed the same nonproprietary names as innovator therapies, it would imply interchangeability, or at least a degree of conferred similarity that pharmacists and payers could use that to justify substituting biosimilars for brand-name biologics. The other key implications of shared nonproprietary naming are different depending on one’s perspective.

The Alliance for Safe Biologic Medicines, a coalition of drug industry and certain medical groups, sees distinguishable nonproprietary naming for biosimilar products as important to ensuring accurate prescribing, safe distribution, and timely reporting of adverse events related to biosimilars.

“Biologics can be highly sensitive to the manufacturing process and identifying specifically which product a patient received is essential to identifying any product-related adverse events,” says Richard Dolinar, the alliance’s chairman.

Arguing for another set of implications is the National Coalition on Health Care. That group, representing seniors groups, unions, pension funds, and consumer advocates is in favor of biosimilars sharing the same nonproprietary name as the brand-name biologics with which they’ll compete.

“The reality is that these are life saving drugs,” says Larry McNeely, Manager of Policy Communications and Advocacy, says of biosimilars. He says that the opposition to biosimilars sharing non-proprietary names with brand-name biologics is a “back-door attempt to undercut serious generic competition for biologics, and could negate the cost-containment potential of biosimilars.”

How the FDA will move ahead on the naming issue is unclear. FDA spokeswoman Sandy Walsh says that naming discussions are still on the table and that naming has been mentioned as a possibility for development of future policies. The issue was discussed at a public meeting organized by the agency in February, but no public meetings to further consider the issue are scheduled at this time.