The US FDA has published long-awaited final guidance on the interchangeability of biologics, calling biosimilar developers to carry out switching studies.

At the last count, there were 19 biosimilar products approved by the US Food and Drug Administration (FDA) US though only a handful have been launched. None of these products have been deemed interchangeable, meaning they cannot be substituted for the reference biologic at the pharmacy level without the involvement of a physician.

However, this theoretically could change going forward through the FDA’s publication this week of final guidance on ‘Considerations in Demonstrating Interchangeability With a Reference Product.’

Image: iStock/marekuliasz

Like the draft guidelines laid out in January 2017, the FDA is recommending firms to undertake ‘switching studies’ to show whether alternating between a biosimilar and its reference product impacts the safety or efficacy of the treatment.

The guidance “gives an overview of important scientific considerations in demonstrating interchangeability with a reference product and explains the scientific recommendations for an application or a supplement for a proposed interchangeable product,” said acting FDA commissioner Ned Sharpless.

He described the guidance as a “significant action that will help promote competition in the biologic market,” providing “clarity for developers who want to demonstrate that their proposed biological product meets the statutory interchangeability standard under the Public Health Service Act (PHS Act).”

Pfizer calls for flexibility

Both payors and biosimilar developers showed concern towards the draft guidance, arguing the need for switching studies restrict the uptake of biosimilar products. The Agency says it considered many of the comments and made changes to provide increased clarity to stakeholders

A spokesperson from the originator drug and biosimilar developer Pfizer told us the firm supports the FDA’s updated guidance “regarding choice of comparator and product presentation considerations in particular.

“However, Pfizer believes FDA could also be flexible when considering study endpoints and overall study design for interchangeability switching studies. We believe this could be done without impacting FDA’s ability to assess whether switching between the interchangeable biologic product and the reference product poses a risk greater than using the reference product without alternating.”

Booster shot of insulin

The guidance may also help support the uptake of biosimilar insulin products, lowering the cost for “the millions of Americans with diabetes,” Sharpless said.

The FDA has been active in bringing such products to the market, and from March 23, 2020, insulin and other biological products previously approved as drugs under the Federal Food, Drug, and Cosmetic Act will be deemed biological products licensed and regulated under the Public Health Service (PHS) Act.

“An interchangeable insulin product may be substituted at the pharmacy, potentially leading to increased access and lower costs for patients,” said Sharpless.

“For chronically used biologic medications patients get at the pharmacy, such as insulin, the ability to have a licensed interchangeable that can be substituted at the pharmacy without the intervention of the prescribing health care professional – much like how generic drugs are routinely substituted for brand name drugs – could be integral to the success of reducing drug prices for patients.”