The fight over how biosimilars should be named in the US isn’t over yet despite the US Food and Drug Administration’s (FDA) use of a non-proprietary name with a random suffix for the second approved biosimilar and plans to do the same for all future biosimilars.

The group of nonprofits and other stakeholders, spearheaded by the Alliance for Safe Biologics, requested in a letter that FDA use meaningful suffixes for biosimilar non-proprietary names, such as the one used with the first biosimilar approval for Zarxio (filgrastim-sndz). The group said meaningful suffixes are preferable to the random suffixes described in the FDA’s draft guidance on biosimilar naming, released in August 2015, and what the agency used for its second approval for Inflectra (infliximab-dyyb).

In that draft guidance, FDA said the meaningless suffixes will help prevent inadvertent substitution (which could lead to medication errors) of biologics that are not determined to be interchangeable by the FDA.

For interchangeable biosimilars, none of which have been approved yet, FDA is still seeking more feedback on whether to use the same suffix as the reference product, or if they should be given a unique suffix.

The guidance came as FDA also released a proposed rule to designate the names of six already-approved biologics. For example, Amgen's Neupogen (filgrastim) would be changed to "filgrastim-jcwp," while Sandoz's Zarxio (filgrastim-sndz) would be renamed "filgrastim-bflm." For Granix (tbo-filgrastim), FDA has proposed removing the prefix "tbo" and a adding a new suffix, making it"filgrastim-vkzt."

Now, the Alliance for Safe Biologics, including three state groups linked to the Biotechnology Industry Organization (BIO), among others, have sent a letter to Leah Christl, Ph.D., associate director of therapeutic biologics and biosimilars at FDA, saying: “Meaningful suffixes are easier for patients, providers and pharmacists to both recognize and remember, thus facilitating accurate association between adverse events and specific products."

The groups also said a survey of 400 prescribers of biologics revealed that they prefer meaningful suffixes over random by a six-to-one margin, while a survey of 401 US pharmacists showed 77% prefer manufacturer-based suffixes over random.

The Biosimilars Forum, BIO and Pharmaceutical Research and Manufacturers of America (PhRMA) also previously called for the agency to use "meaningful" and "distinguishable" suffixes linked to the license holder's name.

Letter to FDA