The FDA is moving away from requiring animal models for investigational new drug (IND) applications for new monoclonal antibodies and some other drug candidates.
Animal testing will be "reduced, refined or potentially replaced" by a suite of new approach methodologies (NAMs), including computational models and human cell lines and organoids, the agency said in an April 10 release.
To make determinations about efficacy, the FDA said it plans to use pre-existing, real-world safety data from other countries where the drug has already been studied in humans.
Unlike the more sudden changes at the FDA and other health agencies recently, animal testing will be phased out over a period of time, according to the announcement. The agency expects to hold a public workshop later in the year to discuss the plan, and broader policy changes will be enacted gradually based on the results of a pilot program that is slated to launch this year.
The pilot program will involve certain drugmakers using non-animal methods to test antibodies in close consultation with the FDA, according to the agency.
Until the requirements are fully phased out, the agency "intends to use mechanisms like case-by-case waivers or exemptions to permit sponsors to omit animal studies if they provide adequate and validated NAM data," a spokesperson for the Department of Health and Human Services told Fierce Biotech in an email.
“For too long, drug manufacturers have performed additional animal testing of drugs that have data in broad human use internationally. This initiative marks a paradigm shift in drug evaluation and holds promise to accelerate cures and meaningful treatments for Americans while reducing animal use,” FDA Commissioner Marty Makary, M.D., said in the announcement. “By leveraging AI-based computational modeling, human organ model-based lab testing and real-world human data, we can get safer treatments to patients faster and more reliably while also reducing R&D costs and drug prices. It is a win-win for public health and ethics.”
The FDA intends to replace animal testing with alternative methods, a term the agency uses for newer drug testing approaches like organs-on-chips and advanced computer models that can simulate human biology. The drug regulator released a report (PDF) in 2021 outlining the FDA’s work on these methods and expressing the agency’s “strong commitment” to moving away from animal testing.
However, the National Association for Biomedical Research (NABR), a non-profit organization that advocates for “ethical and essential animal research,” said in an April 10 statement that these alternative methods are not ready to take center stage yet.
“There is currently no full replacement for animal models in biomedical research and drug development,” according to the non-profit.
“We all want better and faster ways to bring lifesaving treatments to patients,” NABR President Matthew Bailey said in the statement. “But no AI model or simulation has yet demonstrated the ability to fully replicate all the unknowns about many full biological systems.”
The statement goes on to say that the biomedical community is prepared to work with the FDA to ensure that patient safety isn’t jeopardized in the name of innovation.
NABR’s board of directors includes representatives from GSK, Merck & Co., Johnson & Johnson and Charles River Laboratories, and the non-profit said its members include more than 360 universities, medical schools, biopharma companies and more.
Both the NABR and the FDA advocate for the "three Rs approach" to animal testing: reduce the number of animals used, refine techniques to improve lab animal welfare and replace animals entirely when possible.
Congress passed the FDA Modernization Act 2.0 in September 2022, which amended the 1938 law that gave the FDA its regulatory powers to allow for preclinical drug testing to include “non-animal or human biology-based test methods, such as cell-based assays, microphysiological systems, or bioprinted or computer models.”
Congress followed that bill up with the FDA Modernization Act 3.0 in February 2024, which was meant to force a sluggish FDA to implement the earlier bill. Act 3.0 has yet to pass, and was reintroduced in the Senate in January 2025.
The 2.0 measure “allows for the use of non-animal test methods where feasible, but it does not remove the need for animal testing,” the NABR said in the organization’s statement.
The FDA has been moving towards alternative methods for assessing safety and toxicity for some time, Claire Mazumdar, Ph.D., CEO of Bicara Therapeutics, told Fierce Biotech in an April 11 interview.
"I think being able to demonstrate safety in a number of different models is important, and the science is pointing us in that direction," Mazumdar said. "It will be interesting to see if this is really going to change how we think about this, but I think it's still too early to tell."
Mazumdar's thoughts were echoed by the pharmaceutical trade organization Pharmaceutical Research and Manufacturers of America (PhRMA).
"We are pleased to see this initial announcement of FDA’s plans to phase out certain animal testing and are looking forward to more details to understand how this might further expedite drug development," Andrew Powaleny, PhRMA's senior director of public affairs, told Fierce Biotech in an email.
In a July 2024 survey of 350 life sciences professionals by R&D organization Pistoia Alliance, 60% of respondents said they were hesitant to use alternative methods to animal testing due to concerns about regulatory compliance, despite the passing of the FDA Modernization Act 2.0.
In addition, 77% of respondents said they weren’t using non-animal models like cell cultures and organoids in their R&D process.
Animal welfare group PETA lauded the FDA’s decision to move towards ending animal testing.
“PETA applauds the FDA’s decision to stop harming animals and adopt human-relevant testing strategies for evaluating antibody therapies,” the group said in a statement following the announcement. “It’s a significant step towards meeting the agency’s commitment to replace the use of animals.”
Editor's note: Fierce Biotech's Gabrielle Masson contributed to this report.