A Major Update From the FDA: Removing Animal Testing for Monoclonal Antibodies – What This Means for the Future of Drug Development
- Clive Roper
- Apr 23
- 2 min read
On April 10, 2025, the FDA announced a phased plan to reduce and eventually replace animal testing within the drug development process for monoclonal antibodies.
Why did the FDA start with monoclonal antibodies (mAbs)? mAbs often show limited relevance in traditional animal models due to species-specific immune responses, resulting in inaccurate efficacy and safety data. This decision reflects a shift in regulatory science that emphasizes the importance of New Approach Methodologies (NAMs) for safety evaluation and sets an intention that animal testing should become the exception rather than the rule. Embedded in the text is a roadmap that identifies timeframes of up to 3 years and 3-5 years, utilizing 3Rs approaches, and outlines the roles to be played by in vitro human-derived systems (organoids and microphysiological systems), in silico tools and computational modeling, additional innovative platforms, and pre-existing international data.
The 3-year timeframe focus areas include
• encouraging dual submissions of NAMs and animal data
• exploring international pre-existing data
• launching an open-access international repository for drug safety data
• reducing long-term primate studies from six to three months for qualifying mAbs
• actively tracking and quantifying reductions in animal use
The 5-year timeframe focus areas include
• aiming to make animal studies the exception rather than the norm for pre-clinical safety/toxicity testing
• shifting requirements to a NAMs-based default
The FDA cites collaboration with ICCVAM, whose 2024 report on regulatory acceptance of NAMs set a strong foundation for this transition. The agency will incentivize sponsors who utilize NAMs by offering expedited regulatory pathways and promoting successful case studies of non-animal approaches. Additional proposals from groups such as the 3Rs Collaborative (www.3RC.org) and NC3Rs (www.NC3Rs.org) are reflected throughout the roadmap, underscoring that this is a collaborative effort in which each stakeholder contributes to the overall success of the roadmap. 2025 is proving to be an exciting time to be involved in drug development and playing a role in the future of preclinical testing.
Please read both documents together, and remember that this is a roadmap; we, as stakeholders, all have a part to play. Patients are waiting for better treatments to be brought to them faster.
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