FDA sticks with 'suffix' and sets a high bar for interchangeability

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The FDA is sticking with a four-letter distinguishable suffix for biological medicines that is designed to clearly distinguish biosimilars.

The US regulator initially announced the plan in 2015 and confirmed the decision in 2017. At the time, it said the names of all approved biologicals would be retrospectively modified to include the suffix.

However, it has now announced plans to scrap the move to retrospectively apply the suffix while restating its intention to stick with the policy for all future approvals.

The US is the only country to adopt a suffix for biologics and biosimilars. The move has been criticised by some organisations and advocates on the grounds it will undermine the growth of an already struggling biosimilar market.

In a statement, FDA Commissioner Dr Scott Gottlieb said the suffix is meant to "ensure patient safety by helping providers and patients properly identify products where it’s important to be able to distinguish between different medicines and different versions of similar or interchangeable products."

"The naming policy will provide consistency among biologics and will help ensure health care providers and patients have confidence in the safety and effectiveness of any biological product on the market," said Dr Gottlieb.

"To achieve these goals, the unique four-letter suffix that’s incorporated as part of a biological product’s nonproprietary name is being applied to originator products going forward, as well as to any biosimilar and interchangeable products, so they can be appropriately distinguished from one another at the pharmacy level.

"Because biologics are generally complex and typically impossible to replicate in the way small-compound drugs can be, and even though biosimilars have no clinically meaningful differences from the reference product, these unique suffixes are a critical component of the FDA’s ability to track adverse events to a specific biological product and manufacturer so that appropriate action can be taken when needed to protect patients."

The US naming convention is similar to an idea initially proposed but scrapped by the World Health Organisation. 

Its proposal, based on the use of a Biological Qualifier (BQ) comprised of four random consonants in two 2-letter blocks separated by a 2-digit checksum, was officially scrapped in 2017 after countries were unable to reach a consensus on its adoption.

The TGA went through several naming conventions before officially adopting the current approach, under which biosimilars are approved with the same name as their reference biologic, in early 2018.

The FDA approves biosimilars as non-interchangeable or interchangeable. It has approved 17 biosimilars but none are interchangeable with their reference biologic. The regulator also issued guidance late last week on how a biosimilar would be approved as interchangeable.

The guidance requires sponsors to provide "data and information" that demonstrates "the proposed interchangeable product can be expected to produce the same clinical result as the reference product in all of the reference product’s licensed conditions of use."