Breaking: FDA Takes Crucial Step to Accelerate Use of Alternatives to Animal Testing

Today is one of the most impactful days ever in our quest to reduce animal testing in drug development and to replace an old, tired, broken system that relied on tormenting dogs, primates, and other animals with 21^st-century methods grounded in human biology.

The U.S. Food and Drug Administration (FDA) issued a new rule to remove outdated animal-specific terminology from key federal regulations and to make clear that modern, animal-free methods can be used to generate safety information for new drugs and biological products.

The agency, for too long maddeningly unresponsive to public demands to change an archaic and unreliable drug development system, said its new rule removes regulatory language that could suggest animal testing is the only acceptable way to generate safety information. In its place is the broader framework of “nonclinical tests” and “nonclinical studies” — terminology that encompasses human cell-based systems, organs-on-chips, computer modeling, organoids, and other advanced technologies.

It is the latest evidence that the FDA Modernization Act 2.0, enacted in 2022 through the advocacy of Animal Wellness Action, is producing a fundamental shift in the way the federal government approaches drug development, and in turn, the way drugs are developed. It will reduce the number of animals being bred and sold by outfits like Marshall BioResources and Charles River Laboratories, and it will draw down the use of dogs, cats, and other animals in preclinical research run or funded by animal testing contractors to service global giants in the $1.35 trillion pharmaceutical sector. To be clear, 90%-95% of these tests fail to translate to humans in the first place. 

Congress Opened the Door

For more than 80 years, federal law required “preclinical tests (including tests on animals)” before a new drug could advance into human clinical trials.

The FDA Modernization Act 2.0, which we formulated and championed in Congress with Sens. Rand Paul, M.D., R-Ky., and Cory Booker, D-N.J., and Reps. Vern Buchanan, R-Fla., and Buddy Carter, R-Ga., changed that.

Congress replaced that framework with the much broader category of “nonclinical tests” and expressly recognized animal-free methods including cell-based assays, organ chips, and microphysiological systems, computer modeling, and other human-biology-based approaches.

The law did more than change terminology. It removed a statutory barrier that had, for 84 years, mandated animal testing in drug development. It gave the FDA and drug developers a push from Congress to adopt more humane and scientifically sound methods designed around human biology rather than legacy models such as beagles and macaques.

Getting to this point has been excruciatingly slow, but it’s here and it’s a game-changing development for animals.

FDA Is Putting Modernization into Practice

Last year, we told you about a landmark action by FDA: in April 2025, the agency released its “Roadmap to Reducing Animal Testing in Preclinical Safety Studies,” laying out a strategy to reduce and replace animal testing with human-relevant approaches, beginning with monoclonal antibodies and other drugs.

In December 2025, the FDA followed with draft guidance addressing circumstances in which long-term nonhuman primate studies for certain monoclonal antibodies could be reduced or eliminated.

In March 2026, the agency issued broader draft guidance establishing a framework for the validation and regulatory use of new approach methodologies, or NAMs. That guidance addressed one of the most important questions facing developers: what evidence the FDA needs to determine that a new method is fit for a particular regulatory purpose.

The FDA has also moved in oncology and other areas to employ weight-of-evidence approaches that can reduce or eliminate certain animal studies.

This sequence of actions helped create the regulatory infrastructure needed to first kick-start and then advance human-relevant science.

In addition to correcting the incongruity between federal law and agency regulations with today’s announcement, the FDA is also giving pharmaceutical companies and other drug developers practical examples of how these approaches have already been used in the regulatory process.

The FDA is opening the door for these companies to start moving into this new R&D paradigm.

Getting the FDA Modernization Act 3.0 in Place

Prodded by us, Congress has in turn been prodding the FDA.

FDA Modernization Act 3.0 was a response to foot-dragging by the FDA to implement the 2022 law.

The Senate passed its version of 3.0 in December 2025. The House passed H.R. 2821 this year. Clearly, the FDA was paying attention to our work on 3.0.

The FDA’s new rule accomplishes nearly all the specific regulatory modernizations called for in the House bill and makes additional conforming changes of its own.

One more small action by Congress and the president on 3.0 will punctuate these epic gains. Their affirmation of 3.0 underscores that our elected leaders are watching andwant this transition away from animal testing to move ahead with urgency.  Trust but verify.

The FDA Modernization Act 2.0 is a reminder there’s work ahead even after a law passes.

Congress first changed the statute. Then the FDA developed a roadmap. Then came guidance on specific drug classes, the regulatory embrace of alternative methods, and practical examples about how this will work in the real world.

Finally, the FDA is rewriting its regulations, closing the gap between legislation and implementation.

Each step makes the next one easier. Each gives scientists and drug developers more regulatory certainty to invest in technologies based on human biology rather than continuing to rely reflexively on animal models developed generations ago.

This is a big moment in the life of the Animal Wellness Action/Center for a Humane Economy and the broad movement to begin to fix a broken drug-development system with animals long at its core — a system that was costly, ineffective, and inhumane.

Your support makes this happen.