Comparative Review of International Policy, Technological Trends, and Regulatory Acceptance of New Approach Methodologies (NAMs): Cases from the EU, US, and South Korea

Background: Animal testing has historically played a fundamental role in chemical safety assessment and drug development.However, growing concerns about animal welfare, scientific limitations, and societal acceptance have accelerated a global shift towards new approach methodologies (NAMs).These methods aim to reduce, refine, or replace animal use while enhancing predictive reliability and ethical standards in toxicology.Objectives: This review compares policy development, legal frameworks, technological advancements, and industrial application of NAMs in the European Union (EU), United States (US), and South Korea.It identifies key challenges impeding the uptake of NAMs and outlines future directions necessary for their effective implementation and global harmonization.Methods: A systematic review of official reports, peer-reviewed articles, and regulatory documents published between 2023 and April 2025 was conducted.The study focused on contrasting legal structures, regulatory agency roles, scientific and technological progress, international collaboration, and industrial adoption rates of NAMs across the three regions. Results:The EU leads with strong legislation and harmonized policies, achieving over 90% adoption of NAMs in single-dose toxicity testing.Under the FDA Modernization Act 2.0, the US supports the regulatory use of 200 NAM assays but faces challenges with complex toxicities.South Korea has expanded NAM adoption via reforms and pilot projects, yet SME uptake remains low at 18.2%, reflecting persistent barriers.Quantitative indicators (adoption, approval, standalone submission rates, cost reductions) have shown progress, but qualitative barriers-including gaps in infrastructure, validation, regulatory acceptance, industrial uptake, and data interoperability-limit broader adoption. Conclusions:NAMs are driving a shift toward more ethical and innovative toxicology by reducing animal testing.Accelerating global adoption requires improvements in quantitative outcomes alongside strengthening legal frameworks, method validation, global harmonization, industrial strategies, and standardized data management.Ongoing collaboration among governments, regulators, industry, and researchers is essential for addressing the remaining challenges and ensuring successful worldwide NAM implementation.