FDA roadmap to reducing animal testing: a regulatory and scientific paradigm shift in nonclinical safety assessment.

On April 20, 2026, the U.S. Food and Drug Administration FDA published a 1-year progress report of its initiative to reduce animal testing requirement in drug development. The FDA roadmap, announced on April 10, 2025, represented a pivotal paradigm shift toward human-centric New Approach Methodologies (NAMs), including stem cell-derived organoids, organs-on-chips, in silico modeling, and AI-enabled tools. The aim is to address the longstanding challenges of conventional preclinical safety assessment using animal models, including poor translational predictability, high cost, ethical concerns, and inherent interspecies biological differences, resulting in high clinical attrition and delayed access to effective therapies. In this commentary, we critically evaluate the scientific rationale, first-year implementation progress, and global regulatory impact of the FDA initiative. We highlight landmark advances including the permanent Innovative Science and Technology Approaches for New Drugs (ISTAND) program, human-centric validation principles, streamlined nonclinical frameworks for biologics, and alignment with global agencies and regulators. We also discuss existing, persistent challenges, such as uneven validation across toxicological endpoints, incomplete global data sharing, and cultural inertia, and propose actionable strategies to accelerate the safe, systematic adoption of NAMs in regenerative medicine and drug development.