Dispatches from CPhI
INN guidance leaves FDA in catch-22 over awaited interchangeability rules, experts
In August, the US Food and Drug Administration (FDA) called for a random four-letter suffix to be designated to all non-proprietary biological product names in draft guidance largely applauded by innovators and criticised by biosimilar makers.
But by doing so, “the FDA has put itself in a catch-22 situation” when it comes to future guidance on the interchangeability of biosimilars and biological products, according to Michel Mikhail, a regulatory consultant who specialises in biosimilars.
“The proposal to have an INN [International Nonproprietary Name] with an added four-letter rule has left the FDA trapped,” he said during a panel discussion at the CPhI Worldwide Pre-Connect Conference in Madrid yesterday.
Under the rule Amgen’s reference product Neupogen will be known in its license as ‘filgrastim-jcwp’ while its copycat Zarxio – which became the first biosimilar launched in the US last month - will be named ‘filgrastim-sndz.’
“When interchangeability guidelines come along there shouldn’t be any need for this four-letter distinguisher,” Mikhail said, as having a differentiator defeats the purpose of a product being interchangeable.
Industry awaits guidance
The FDA is already facing criticism from the Senate Committee on the current lack of interchangeability guidance and the INN guidelines could lead to further delays in publication.
Interchangeability and Substitution
In the EU, substitution and interchangeability differ on meaning. Substitution is done at a pharmacy level but requires a physician’s approval, while if a biosimilar is interchangeable it can be freely switched with its reference product (or another biosimilar) by a pharmacist.
In the US, a biosimilar needs to be approved by the FDA for ‘biosimilarity’ and then, if requested by the biosimilar manufacturer, needs to be approved as an ‘interchangeable’ with its reference product. There are also state laws on interchangeability and substitution which vary state by state for biologics.
Paul Greenland, VP of biologics at biosimilar developer Hospira, told the room the arrival of Zarxio in the US was “a real milestone for biosimilars,” but the product is not deemed interchangeable with Neupogen, and industry is still concerned about what is needed to ensure a product can be substituted for its reference biologic.
“Interchangeability has been established for a long time for small molecules, but for biosimilars the rules need to be reconsidered,” Greenland said. “What evidence is going to be needed for this is currently unknown.
“To some extent, the whole industry is awaiting these guidelines, if the FDA is able to come up with these at all.”
