FDA Reaches Key Goals for Reduction of Animal Testing in Drug Development

On April 20, 2026, FDA announced it has reached key first-year goals that were set for the implementation of the April 2025 Roadmap to Reducing Animal Testing in Preclinical Safety Studies,1 an effort by the agency to modernize drug development and reduce testing on animals.2 To detail its efforts, the agency released a report, Reducing Animal Testing in Nonclinical Studies Year One Progress and the Path Forward April 2026,3 updating its progress in minimizing animal use in drug development.

In the past year, FDA has released a draft guidance on the reduction or elimination of nonhuman primate testing in monoclonal antibody development4 and updated a guidance on transitioning away from horseshoe crab-derived endotoxin testing. A draft guidance expanding the use of weight-of-evidence approaches to support the use of new approach methodologies (NAMs) was published in March 2026,5 enabling the use of in vitro assays, computational toxicology, and other human-relevant models to generate evidence across a wider array of safety endpoints.

The agency has also worked on accepting safety data from sources other than animal testing in drug approvals, such as data from other countries where the drug is already being used by humans. It also qualified an artificial intelligence tool for leveraging in silico models in regulatory decision-making. And a searchable database was launched that clarifies which alternative methods can be used.

What Are the Benefits of Limiting Animal Use?

According to FDA, animals are not a good model for how drugs perform in the human body. Most drugs (90%) that clear animal studies do not get FDA approval because of safety or efficacy problems in humans. The agency believes NAMs, such as in vitro systems, computational modeling, and human-derived platforms, reflect human biology better and improve the prediction of drug effects.

In similar efforts, the US Pharmacopeia (USP) released a chapter in 2024 on endotoxin testing using non-animal derived reagents.6 In an episode of PharmTech’s Ask the Expert, Susan J. Schniepp, distinguished fellow at Nelson Labs, and Siegfried Schmitt, PhD, vice president, Technical, at Parexel, explained how the USP chapter may impact industry.7

“Twenty years ago, the predominant test procedure for determining endotoxin level, or pyrogen level, as we called it, was the rabbit test. And we used to actually inject rabbits, which was a very subjective because you'd measure their temperature,” said Schniepp. “And then we evolved to using the limulus amoebocyte lysate or LAL test, and there was the chromogenic [test] but they were all predicated off the horseshoe crab. So now we're moving forward to reagents for this test, which is critical to the release of sterile injectables that does not involve animals. So absolutely, we should consider this.”

How Will FDA Maintain Progress?

“One year ago, we issued an ambitious roadmap to eliminate unnecessary animal testing and replace animal testing with more precise ways of predicting drug safety in humans,” said FDA Commissioner Marty Makary, M.D., M.P.H., in a press release.2 “In addition to ushering in more scientifically accurate way to test drugs before they are used in humans, the agency has made great strides to reduce research and development costs, which will lower drug prices for everyday Americans.”

The agency has created a permanent pathway for qualifying innovative drug development tools, cross-center scientific reviews, and a formal partnership with the National Institutes of Health to shift toward human-relevant science as the default approach to drug evaluation. FDA hopes this direction will improve drug safety, accelerate drug development, and reduce costs, all while reduce the use of animals.

References

1. FDA. Roadmap to Reducing Animal Testing in Preclinical Safety Studies. FDA.gov. April 2025. Accessed April 21, 2026. https://www.fda.gov/media/186092/download?attachment
2. FDA. FDA achieves year 1 goals in reducing animal testing in drug development. Press release. April 20, 2026. Accessed April 21, 2026. https://www.fda.gov/news-events/press-announcements/fda-achieves-year-1-goals-reducing-animal-testing-drug-development
3. FDA. Reducing Animal Testing in Nonclinical Studies Year One Progress and the Path Forward April 2026. Accessed April 21, 2026. https://www.fda.gov/media/191986/download?attachment
4. FDA. FDA releases draft guidance on reducing testing on non-human primates for monoclonal antibodies. Press release. December 2, 2025. Accessed April 21, 2026. https://www.fda.gov/news-events/press-announcements/fda-releases-draft-guidance-reducing-testing-non-human-primates-monoclonal-antibodies
5. FDA. General Considerations for the Use of New Approach Methodologies in Drug Development Guidance for Industry, Draft Guidance. March 2026. Accessed April 21, 2026. https://www.fda.gov/media/191589/download
6. USP. Chapter for endotoxin testing using non-animal derived reagents published for early adoption. Press release. November 1, 2024.
7. Thomas F, Haigney S. Non-animal-derived reagents for endotoxin testing. PharmTech.com. November 21, 2024. Accessed April 21, 2026. https://www.pharmtech.com/view/non-animal-derived-reagents-for-endotoxin-testing