Category: 351(k) pathway

Tracking Two Bills to Remove the Clinical Efficacy Study Requirement for Biosimilar Development

Proposals in the House and Senate, both titled the Expedited Access to Biosimilars Act, may officially remove the FDA’s requirement for clinical efficacy studies for biosimilar candidates.

On July 15th, a new bipartisan bill was introduced into the House of Representatives that would expand access to biosimilars by modernizing the FDA’s biosimilar approval process. This could be paired with a similar proposal just reaching Senate Committee discussion. Both of these proposals seek to reduce the cost of biosimilar development through squeezing out the need for comparative efficacy studies.

Expedited Access to Biosimilars Act

As reported earlier, the FDA in October 2025 announced a draft guidance that would achieve the same end, to remove the mandate for late-stage clinical efficacy trials for biosimilar manufacturers. However, a final guidance has not yet been released.

Introduced by Representatives Nick Langworthy (R-NY) and Kim Schrier, MD (D-WA), the Expedited Access to Biosimilars Act (HR 9661) could codify long-awaited regulatory changes to comparative trial expectations in the 351(k) biosimilar pathway.

According to a press release from Congressman Langworthy’s office, the act would eliminate unnecessary regulatory hurdles while preserving the FDA’s authority to require additional studies whenever scientifically warranted. This supports the October 2025 announcement of a draft guidance for removal of a mandate for phase 3 clinical efficacy studies for biosimilars. A key stipulation of the proposal would be a requirement for FDA to notify manufacturers early in the review process if additional late-stage comparative efficacy studies will be required. The aim would be to provide greater certainty around the clinical trial resources required for a successful biosimilar application process as well as avoiding unnecessary delays in the application process.

A number of associations have express support for the legislation including the Association for Accessible Medicines, the American Society of Health-System Pharmacists, and America’s Health Insurance Plans, among others.

The Senate’s 2025 Proposal

A Senate proposal by the same name (S.1414), introduced in April 2025 by Senator Rand Paul (R-KY), seeks largely the same goals. It has languished in the Committee on Health, Education, Labor, and Pensions, without additional cosponsors, until now. A committee meeting is scheduled for July 22 to finally consider this legislative proposal. It has one co-sponsor (Sen. Mike Lee, R-UT).

We’ll be monitoring whether the Expedited Access to Biosimilars Act can break through for an eventual debate and vote on either the House or Senate floor.

This article was written by our Director of Content, Stanton Mehr. Stan has been writing commentary and reporting news about the biosimilar industry since the submission of the first biosimilar 351(k) application to the FDA 13 years ago. Since that time, BR&R has been tracking the US biosimilar marketplace, with the industry’s original, comprehensive and updated database of biosimilar filings with the FDA.

When is a Biosimilar a Biosimilar?

In 2026, is the definition of a biosimilar the same for countries’ drug regulatory systems around the globe? A recently published scoping survey attempted to answer the question.

Although there has been a decade of interest in moving towards global biosimilar regulatory standards, we first must answer a more foundational question: Is the definition of a biosimilar the same worldwide?

You may suspect that the answer is obvious, but then again, why are we asking it? Is it a trick question? Years ago, the answer was not so simple. Those of us covering the biosimilar field in the 2010s will recall that some Indian companies, for example, were producing what might be considered “follow-on” medicines by the FDA’s regulatory standards, but were promoting them as biosimilars.

No Guidances by FDA on Follow-on vs. Biosimilar Products

Global biosimilar regulation

The FDA’s own regulatory definition was not set in stone: Basaglar, the second insulin glargine product to receive FDA approval, is a biosimilar but technically not a biosimilar. Even today, there may be some confusion as to whether Basaglar is considered a biosimilar or a follow-on product. It was indeed approved by the FDA under a 505(b)2 application, principally because insulins were not considered eligible for the 351(k) approval pathway until 2020. The FDA would probably support that it is clinically equivalent to Lantus in any way that matters. Yet, from a regulatory perspective, it was not evaluated as part of the biosimilar pathway, so it cannot be designated a biosimilar.

The same can be said for Granix, the second filgrastim product approved by the FDA, which underwent its approval process before the 351(k) was implemented (and under which Zarxio was licensed). It is important to note that the FDA itself has not tried to improve clarity by announcing retrospectively that these agents can be considered either biosimilar or an equivalent.

A Survey of Biosimilar Definitions

So, is a biosimilar a biosimilar throughout the world? An article published in JAMA Health Forum described a survey of 19 countries’ biosimilar regulatory guidelines. These included 12 with emerging and developing economies and 7 with advanced economies, according to the World Health Organization classification. The authors, from the University of San Francisco and GlaxoSmithKline, found that most countries define “biosimilarity as the absence of differences in the medicine’s quality, safety, and efficacy compared with the RP. Sixteen countries explicitly required comparability exercises to demonstrate biosimilarity, and 13 countries specified that the same RP must be used in these studies.

“Of the 19 countries in the study sample, 17 (89%) have adopted the WHO’s biosimilar terminology; the exceptions were Indonesia, which uses the term follow-on biological in addition to biosimilar, and Tanzania, which uses the term similar biotherapeutic product. A total of 17 countries (89%; except India and South Korea) define biosimilarity according to the absence of differences in quality, safety, and efficacy between the biosimilar and the reference product, although in some countries (Egypt, Turkey, UK, and US), this is heavily implied rather than explicitly stated. Most countries (n = 16 [84%]) require comparability exercises (by definition), but 3 (Mexico, Indonesia, and China) do not explicitly include this requirement.”

The authors also stated that all advanced economies waived the need for clinical efficacy and immunogenicity testing when justifiable, but guidelines from emerging and developing economies differed on clinical study waivers.”

Interestingly, one of the areas of least consensus is that of biosimilar naming and labeling guidance provided. Countries such as France, Germany, Japan, and South Korea do not specify any requirements, whereas the UK, US, and Canada do, among the WHO advanced economic sector. Among countries in the emerging and developing economic region, China and Mexico do have naming and labeling guidelines, whereas Brazil, India, and Indonesia do not. The area of greatest agreement seemed to be in acceptance of extrapolation, with all but Saudi Arabia among the surveyed countries with published extrapolation guidelines.

Scoping surveys such as this are necessary steps in a march towards global regulatory standards for biosimilars. They show not only how far we’ve come in reaching basic agreements, but also how far we need to go. Perhaps, most importantly, they show us areas where a push for global standards would have the least likelihood of success.

This article was written by our Director of Content, Stanton Mehr. Stan has been writing commentary and reporting news about the biosimilar industry since the submission of the first biosimilar 351(k) application to the FDA 13 years ago. Since that time, BR&R has been tracking the US biosimilar marketplace, with the industry’s original, comprehensive and updated biosimilar approval database.