The FDA naming guidelines for biosimilars are designed to level the playing field, so that patients will not discriminate against the less pricey, often as effective, biosimilar version of another drug. But the guidelines have prompted confusion, which pharmacists worry could lead to mistakes in dispensing.
The guidelines say biosimilar drugs must each bear a meaningless unique four-letter code. Before the guidelines were finalized, a biologic manufacturer might condense their company name into a four-letter code to distinguish it from biosimilar versions. That is no longer an option.
Not knowing the maker of a biosimilar and having to remember a meaningless code can make a pharmacist’s job more difficult. “Under the current naming system, each biological product will have a proper name including a core name and a unique but meaningless four-letter suffix separated by a hyphen,” says Sam Li, PhD, assistant professor, Health Outcomes and Policy Research, University of Tennessee College of Pharmacy. “For example, the latest FDA-approved biosimilar, Fulphila (pegfilgrastim-jmdb, Mylan), has followed this naming convention. Pharmacists are familiar with the core name. The suffix, however, is new and very difficult to remember. When several biological products with the same core name are available on the market, it is challenging to tell which suffix belongs to a specific manufacturer.”
James G. Stevenson, PharmD, FASHP, a professor at the University of Michigan College of Pharmacy, also sees potential for confusion and a possible negative effect on patient safety.
“Specifically, the use of a ‘nonmemorable' suffix is likely to create confusion for both patients and healthcare practitioners,” Stevenson says. “We still only have three biosimilars on the U.S. market and two are infused products—so the actual problems are likely to become more evident when there are more products on the market.”The new system may require pharmacists to spend extra time communicating with patients and healthcare providers.
“Because the suffix is meaningless and difficult to remember, pharmacists always need to double check the manufacturer information to prevent medication errors,” says Li.
The naming system will be applied to both newly licensed originators and biosimilars, and will likely require changing some previously licensed biological products, says Li.
“For example, Neupogen (filgrastim, Amgen)—the reference product of Zarxio (filgrastim-sndz, Sandoz)—was approved by the FDA before the release of the naming system,” he says.
The new naming system offers advantages to biosimilars, possibly leveling the playing field. “When the originator and biosimilar use different naming systems, patients might have an impression that the biosimilar is different or even inferior to the originator,” says Li. “With the current naming system, patients will not misinterpret the relationship between the originator and biosimilar.”
The FDA approach may have been conceived to facilitate pharmacovigilance, says Stevenson, but he’s not sure it will work.“I’m doubtful that this approach will be effective, especially if patients and providers are confused about which product the patient is actually taking. I think the FDA approach would be effective if the distinct suffixes had some meaning, for example, if they represented the manufacturer of the product.”
Meaningless suffixes are unpopular among pharmacists, according to surveys. “Meaningful suffixes are memorable,” says Li. “It could reduce the burden for patients and healthcare professionals to link a suffix to a specific manufacturer.”
In a 2016 paper, Stevenson recommended that biosimilars have a common United States Adopted Name with a reference product, along with a suffix that is memorable to help prevent inadvertent switching.