Skip to main content
Physicians Committee Urges FDA to Revise Draft Guidance on Using NAMs in Drug Development
In March 2026, the Food and Drug Administration issued draft guidance, General Considerations for the Use of New Approach Methodologies (NAMs) in Drug Development, to help pharmaceutical companies reduce their reliance on animal studies used to support regulatory submissions.
NAMs include simple in vitro and chemical reactivity assays, complex cell culture systems, and computational modeling that can better predict outcomes in humans. The FDA described the draft guidance as another major milestone in the implementation of its roadmap to reduce animal testing and move away from using animal studies as the default source of drug safety information.
While we welcome the draft guidance, the Physicians Committee submitted extensive public comments recommending targeted revisions to make it more useful to regulators and drug developers, and more protective of patients and animals.
The draft guidance comes at a pivotal time. In April 2025, the FDA released its Roadmap to Reducing Animal Testing in Preclinical Safety Studies, outlining a strategic approach to reduce animal testing through the use of NAMs. One year later, the FDA reported progress toward that goal, including new draft guidance documents and the launch of a searchable database of accepted NAMs. These developments reflect years of work by the Physicians Committee and others to make animal experiments the exception, rather than the rule, in drug development.
A Strong Start
Perhaps most importantly, the FDA’s draft guidance affirms that NAMs do not necessarily need to be validated to be considered for regulatory review. Validation is a process by which the accuracy, reliability, and relevance of a test method or testing strategy are established for use in a specific context. While validation is important to help determine the quality of the data produced and how the results should be interpreted, the lengthy process can sideline promising, human-centric methods while drug developers continue to rely on historically used animal studies. The FDA’s draft guidance recognizes that fit-for-purpose NAMs, even if not validated, may still adequately address specific toxicological concerns as well as contribute to the weight of scientific evidence on which regulatory decisions are ultimately based. As the FDA gains confidence in NAMs, they could be adopted to reduce or replace specific animal studies.
The draft guidance also builds on recent reports by the National Academies of Sciences, Engineering, and Medicine; the FDA’s Science Board; and the Interagency Coordinating Committee on the Validation of Alternative Methods. These reports support a framework that holds both NAMs and animal studies to the same standard: whether they address outcomes in the patient population under clinically relevant exposure conditions. They also support building confidence and experience with using NAMs through flexible, fit-for-purpose strategies that consider their intended uses.
Targeted Revisions
Our comments and revisions place the FDA’s recommendations within the broader context of building confidence in the use of NAMs to support regulatory decisions. While the draft guidance notes that NAMs do not necessarily need to be validated, its focus on validation could still lead drug developers and regulators to delay using and accepting NAMs until the formal process is complete, even when NAMs are fit-for-purpose and can contribute to the weight of scientific evidence. We also emphasize the central role of human relevance. Comparisons between NAMs and historically used animal studies should be guided by human evidence, when available, and by the health or safety question each is intended to inform—not by presuming that historically used animal studies are the gold standard. Finally, we highlight that validation is not one-size-fits-all. Strategies for building confidence in NAMs should be tailored to the method, its relevance, and its intended use, while defining that use broadly enough to avoid requiring separate validation for closely related applications.
We hope the FDA will consider our comments in preparing a revised draft guidance. As always, we are committed to working with the FDA to achieve our shared goal to reduce and replace animal testing in drug development.
