The U.S. Food and Drug Administration (FDA) on April 10, 2025, announced a significant policy shift aimed at reducing its reliance on animal testing for drug development and incorporating new approach methodologies (NAMs) such as use of in silico models or other approaches. According to FDA, the "animal testing requirement will be reduced, refined, or potentially replaced using a range of approaches, including AI-based computational models of toxicity and cell lines and organoid toxicity testing in a laboratory setting."
The FDA Modernization Act 2.0, passed in late 2022, authorized the use of non-animal alternatives for investigational new drug applications, paving the way for this transition. However, FDA has been slow respond to implement and permit the use of NAMs. This recent announcement is part of the FDA's broader strategy to incorporate NAMs, which utilize advanced scientific techniques to enhance drug safety and efficacy assessments while minimizing animal use. FDA also released a roadmap that emphasizes the adoption of NAMs such as organ-on-a-chip systems, computational modeling and advanced in vitro assays to replace traditional animal testing methods.
Immediate Future
In the immediate future, FDA will initially focus on monoclonal antibodies (mAbs) and other biologics that currently require extensive animal testing for safety and efficacy evaluations. The FDA plans to expand this approach to other biologics and eventually to new chemical entities, which is permitted based on the FDA Modernization Act 2.0. Additionally, FDA announced it will use preexisting, real-world safety data from other countries with comparable regulatory standards, where the drug has already been studied in humans, to make determinations of efficacy.
The FDA plans to provide additional guidance to inform sponsors on these changes. The FDA aims to make animal studies the exception rather than the norm within the next three to five years, with NAMs covering all critical areas of drug safety and efficacy testing. Drug and biologic companies in early drug development should prepare for changes in preclinical testing requirements as NAMs become more integrated into regulatory submissions and recognize that the development of new NAMs to replace animal testing will take time and manpower from FDA. Effective immediately, companies are encouraged to submit NAM data alongside traditional animal data to build a repository of experience and potentially reduce the need for animal testing.
The FDA's new policy has bipartisan congressional support. On April 11, 2025, Rep. Earl L. "Buddy" Carter (R-Ga.), along with Rep. Nanette Barragán (D-Calif.) and others, reintroduced the FDA Modernization Act 3.0. This bill directs the FDA to fully implement provisions intended to reduce unnecessary animal testing for drug development from the 2022-enacted legislation.
The FDA's decision to reduce reliance on animal testing marks a pivotal shift in the agency's regulatory posture and a welcome to those sponsors already adopting NAMs. The announcement includes initial steps on implementation such as a narrowed pilot program, but it is indicative of a broader shift in FDA policy. Companies should stay informed about regulatory updates and consider investing in NAM technologies to align with the FDA's evolving standards.
