FDA Shifts Away From Animal Testing: A Paradigm Shift in Biomedical Research

The Food and Drug Administration (FDA) is enacting a significant change in biomedical research, moving away from reliance on animal testing towards new approach methodologies (NAMs) for evaluating the safety and efficacy of drugs and biologics. This shift, initially signaled in April 2025, is gaining momentum with the implementation of the FDA Modernization Act and is poised to impact research, development, and animal welfare.

The Evolution of FDA Policy

In April 2025, the FDA announced plans to reduce animal testing requirements, particularly for monoclonal antibodies and other medications. This decision was further solidified by the FDA Modernization Act 2.0, signed into law in December 2022, which allows for the use of non-animal and human biology-based test methods, such as cell-based assays and computer modeling. The FDA Modernization Act 3.0, passed by the Senate in December 2025 and awaiting House action, aims to align regulations with this new framework, removing language that defaults to animal testing.

Scientific Relevance and New Approach Methodologies

Experts emphasize that this move isn’t solely about ethics or cost, but about scientific relevance. Data suggest that animal testing often fails to accurately predict a drug’s effects in humans, particularly for biological drugs. New approach methodologies (NAMs) – including cell cultures, organ-on-a-chip systems, computer modeling, and artificial intelligence – offer more human-relevant ways to study disease and assess drug safety.

However, researchers stress that NAMs and animal studies are not mutually exclusive. They form a continuum, with NAMs complementing, rather than replacing, the complexity of whole living systems.

FDA and NIH Collaboration

The FDA and National Institutes of Health (NIH) held a workshop in July 2025 to discuss collaboration in reducing animal research. Following the workshop, a public comment period was opened to gather external input for interagency programs advancing NAMs. In December 2025, the FDA issued draft guidance on reducing nonhuman primate use in monoclonal antibody toxicity studies, as part of its Roadmap to Reducing Animal Testing in Preclinical Safety Studies.

In Silico Solutions and Artificial Intelligence

In silico approaches, including computational models, simulations, and artificial intelligence, are playing an increasing role in drug development. In vitro approaches, such as tissue chips and organ-on-a-chip systems, are also being utilized. While promising, these methods currently cannot fully replicate a whole living organism and are most effective when used in combination with animal studies.

The FDA roadmap emphasizes integrative combinations, such as organ-chip toxicity combined with pharmacokinetic modeling and AI-based predictors, to address areas historically covered by whole-animal studies. AI and machine learning can aid predict toxicity and immunogenicity risk, but transparency and uncertainty quantification are crucial for trustworthy results.

Implications for Rheumatology

The shift away from animal testing has significant implications for rheumatology, where many therapies target immune mediators. Animal models of autoimmune disease often fail to capture the complexity of human disease, and the FDA’s new approach may expedite access to novel biologics and biosimilars.

However, careful consideration must be given to safety, particularly for monoclonal antibodies and treatments for rarer rheumatic diseases where sufficient toxicity data may be lacking.

Looking Ahead

While the FDA Modernization Act 3.0 does not prohibit animal studies entirely, it aims to remove outdated regulatory language requiring them. The successful integration of NAMs and animal research will require ongoing collaboration, standardization, and validation. This evolving landscape promises to reshape biomedical research, potentially accelerating drug development while reducing reliance on animal testing.