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FDA Modernization Act 2.0 – what, if anything, has changed in US regulations?

New legislation in the US has been hailed by animal rights groups as a ban on animal testing – in reality, very little has changed. EARA Executive Director, Kirk Leech, examines the facts.

Last December, new legislation (FDA Modernization Act 2.0) updated the procedures for how the Food and Drug Administration (FDA), the federal agency which approves new drugs for use within the US, conducts its safety tests.

Effectively, the new Act is a bureaucratic tidying up of existing legislation, bringing the wording into the modern age. Its amendments now make it clearer that drug companies can use both animal and non-animal methods in preclinical research to demonstrate to the FDA the safety and efficacy of new drugs before they go to into human trials and use.

However, these were already the legal requirements for the pharmaceutical industry, both in the US and also in separate EU legislation. Read this short explanation of the drug testing process by Curious Science Writers.

FDA Modernization Act 2.0 in detail

To be clear, the legislation does not actually ban animal testing. Rather, it allows the use of alternatives, such as organs-on-a-chip that recreate human physiology in a microchip, studies of human cells and computer simulations.

The new Act does not restrict the use of animals in scientific research, but has changed the wording of the legislation, now specifying what data is required to allow the testing of new drugs in humans.

The Act previously said that it required preclinical tests (including the use of animals) to test drug safety and efficacy, but this specific reference to animals has now been removed and simply adds non-animal methods (known as new approach methodologies, or NAMs) – something that the research sector was already allowed to use in drug testing.

In Section 3209 of the new Act entitled Animal Testing Alternatives, the bill amends the regulatory guidance for the FDA that requires animal testing for drugs and biosimilars. The bill amends the Federal Food, Drug, and Cosmetics Act (FFDCA) – which dates back to 1938 – as follows:

  • Substitute the term ‘nonclinical tests’ for the current ‘preclinical tests’ (including tests on animals)

  • Substitute the term ‘animal’ for ‘nonclinical tests’

  • Add a new section defining ‘nonclinical tests’ to include human-relevant testing methods such as cell-based assays, microphysiological systems (such as organ-on-chip), or bioprinted or computer models.

The amendments do not either exclude or call for a reduction of animal research for testing in the preclinical phase of drug development.

Importantly, the code of federal regulations for the FDA remains the same: preclinical safety and efficacy testing of drugs typically includes a whole intact living system, including a rodent species and a non-rodent mammalian species.

To quote the FDA guidance:

In principle, the duration of the animal toxicity studies conducted in two mammalian species (one non-rodent) should be equal to or exceed the duration of the human clinical trials up to the maximum recommended duration of the repeated-dose toxicity studies.


In their celebration of the passing of the Act, and to the delight of their supporters, the co-sponsors of the bill in the Senate, Senators Rand Paul (R-KY) and Cory Booker (D-NJ), put their own slant on these bureaucratic definitions.

Senator Paul said: “"The passage of this bipartisan bill is a step toward ending the needless suffering and death of animal test subjects – which I’m glad both Republicans and Democrats can agree needs to end.” Senator Booker said: “The passage of my bill will avoid the needless suffering of countless animals, now that experimental drug testing can be done with modern non-animal alternatives that are more scientifically relevant.”

Unfortunately, seizing on the claims by politicians, which were amplified by international animal rights groups, the media response to the amendments in both the USA and in Europe has been confused, and gives the impression to the general public that there has been a significant downgrading of the use of animals in research.

Here are some examples of this:

Eurogroup for Animals Major success in the USA: new drugs no longer have to be tested on animals for approval

(Not the full story as animals can only be replaced if there is an alternative non-animal method and very few suitable alternatives currently exist).

Mother Jones – The US Just Greenlit High-Tech Alternatives to Animal Testing (Approved alternatives to animal testing were already being used by the FDA).

VeryWellHealth FDA: New Drugs Don't Need Animal Testing Before Human Trials (In contradiction to the headline, the article then correctly says, ‘Experts say that companies can use updated technology and artificial intelligence when making drug submissions, but more research is needed to determine if these are viable alternatives to animal testing’).

The FDA tackles misinformation

In response, FDA spokespersons have given interviews seeking to improve public understanding of the FDA Modernization Act 2.0:

  • US National Public Radio An FDA spokesperson told NPR that it will 'implement all applicable provisions in the omnibus and continue to work with stakeholders to encourage the development of alternative testing methods’.

  • Wired magazine In an emailed statement, a spokesperson for the agency wrote that the new law does not change the regulatory process for drugs: ‘The FDA will continue to ensure clinical investigations of drugs are reasonably safe for initial use in humans’.

Previously, in 2022, the FDA stated at a public meeting of its science board and also in a journal article that only a handful of NAMs have so far been validated for drug safety and efficacy testing, and that further animal research is necessary to validate additional NAMs.

This was backed up by Jim Newman, communications director at Americans for Medical Progress, which advocates for animal research, when asked about the new FDA legislation: “Non-animal technologies are still in their infancy and won’t be able to replace animal models for many, many years.”

Will the Act have any effect in Europe?

The passing of the FDA Modernization Act 2.0 does not change how animals that are used in drug testing are regulated in Europe.

From a European perspective, one way to understand these amendments in the USA is to hypothesise that a new regulatory law was passed in the European Parliament that said that animals can only be used in research in the EU if:

the potential results are important enough to justify the use of animals, the research cannot be done using non-animal methods, the minimum number of animals will be used, any discomfort or suffering is kept to a minimum by appropriate use of anaesthetics, etc’.

If that statement were approved by Parliament then these new regulations would simply reinforce the existing legal position in the EU (such as Directive 2010/63/EU), and reaffirm what already exists, which is that:

Animals can only be used in research in the EU when there is a convincing scientific justification, when the expected benefits of the research outweigh the potential risks in terms of animal suffering and when the scientific objectives cannot be achieved using non-animal methods', and that ‘Only projects that fulfil these requirements are authorised, etc’.

Accidental or deliberate misrepresentation?

The terminology of ‘modernization’ needs greater scrutiny. The use of the term is part of the growing narrative of those opposed to the use of animals in research, which is to characterise those who support the continued use of animals in research as old-fashioned and outdated, whereas those who believe that NAMs can immediately replace animal use are seen as forward thinking and innovative.

EARA believes that the biomedical sector should be much more assertive about the reality of NAMs and the fact that they are still not available in many areas of research. They are more often likely to be used in conjunction with animal studies, rather than as a direct replacement.

It is also worth noting that the activist response to the Act follows a pattern identified by EARA sometime ago, in that the further one is away from where regulatory amendments are debated or proposed, the greater opportunity there is for misinterpretation – accidental or intentional. For instance, when a report came out of the FDA saying that it aimed not to use dogs in toxicology studies (something that was simply an aspiration), it was stated as fact by European activists and their supporting MEPs that dogs were now no longer needed in research. The argument went, ‘if the USA can ban dogs, then so can we’. The same process took place, in the opposite direction across the Atlantic, in response to the aspiration of the Dutch Government to be a world leader in ‘animal-free science’ – something they have since very much rowed back on by removing from their official plans and deadline date for achieving this. The response of activists in the USA was, ‘If Europe is banning animal research, we can too’. A similar call and response occurred when news of the European Parliament vote to speed up the ‘phase-out of animal research’ in September 2021. End


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