FDA Lays Out Next Phase of Plan to Reduce Animal Testing
FDA says it will expand efforts to reduce animal testing in drug development after reporting significant first-year progress under its roadmap to modernize nonclinical studies, with upcoming steps focused on scaling alternative methods, improving data infrastructure, and tightening global coordination.
In a new report, Reducing Animal Testing in Nonclinical Studies: Year One Progress and the Path Forward, the agency outlines a series of next-phase priorities aimed at making animal studies “the exception rather than the rule” in safety testing.
Building on initial gains, FDA’s immediate focus will be extending reduced animal testing frameworks beyond monoclonal antibodies — the first category targeted under the roadmap — to include other biologics, new chemical entities, and medical countermeasures. The agency plans to apply its “weight-of-evidence” approach more broadly, combining shorter-duration animal studies with human-relevant data sources such as in vitro assays and computational models.
To track whether those efforts are translating into measurable change, FDA says it will implement new metrics and monitoring systems across drug development programs. These systems are intended to quantify reductions in animal use and identify areas where alternative methods — often referred to as new approach methodologies (NAMs) — are having the greatest regulatory impact.
Validation remains a central bottleneck, and the agency signaled it will prioritize coordinated efforts to qualify NAMs for high-value safety endpoints. That includes expanding work on organ-on-chip platforms, computational toxicology models, and advanced cell-based assays, particularly in areas where animal testing still dominates, such as chronic and developmental toxicity.
Another major initiative involves completing an open-access toxicity data repository first envisioned in the roadmap. While groundwork has been laid, FDA acknowledged that full implementation will require further progress on data standardization, governance, and international data-sharing agreements.
Rather than replacing animal tests one-for-one, FDA emphasized a shift toward integrated testing strategies. Future regulatory decisions are expected to rely on combinations of methods — spanning in silico modeling, laboratory assays, and human data — assembled into comprehensive “toolboxes” tailored to specific safety questions.
At the same time, the agency highlighted the need for continued international harmonization. As alternative methods become more complex and context-specific, aligning regulatory expectations across major markets will be critical to industry adoption. FDA said it will continue working through multilateral forums and bilateral partnerships to ensure that developers can rely on consistent standards globally.
FDA also pointed to the need for broader cultural change across the drug development ecosystem. That includes increasing sponsor confidence in proposing alternatives, strengthening reviewer expertise in evaluating novel methods, and improving public understanding of non-animal testing approaches.