Last week the US Food and Drug Administration (“FDA”) provided guidance on the Nonproprietary Naming of Biological Products. Each biologic, whether originator, related product or subsequent entry (biosimilar) will now be given a non-proprietary name comprised of a core name and a meaningless four-letter suffix. This is an important divergence from the practice in Canada and the European Union where a suffix is not required. It also differs from the practice for the naming of traditional or small-molecule drugs.

According to the FDA, the inclusion of a suffix is intended to facilitate pharmacovigilance and minimize inadvertent substitution of biologics that have not been deemed interchangeable. Critics worry that a suffix will only add confusion, particularly given the random nature of the suffix.

Because reference biologics and biosimilars will now bear different non-proprietary names in the US, questions around interchangeability will be raised. Interchangeable products generally have identical non-proprietary names. Interestingly, in spite of this naming convention, the FDA appears to be the regulator to have given the most thought to the possibility of declaring biosimilars to be interchangeable with their reference biologics, and they have provided a mechanism by which such a declaration may be sought. Health Canada leaves the decision with the Provinces and the European Medicines Agency leaves such determinations to Member States.

This situation poses challenges for global interchangeability messaging for both the innovators and follow-on manufacturers.