Impact of CONCEA's normative resolutions on animal use in regulatory testing in Brazil: a quantitative assessment

Introduction: Alternative testing methods based on the 3Rs principles (Replacement, Reduction, and Refinement) have increasingly been incorporated into regulatory toxicology. In Brazil, the creation of the National Council for the Control of Animal Experimentation (CONCEA) in 2008, has driven the recognization of validated alternative methods. Since 2014, CONCEA has published Normative Resolutions (NRs) recognizing alternative methods aligned with replacing or reducing traditional animal-based tests. Objective: This study aimed to quantitatively assess the impact of NRs 18/2014, 31/2016, 45/2019, and 56/2022 on animal use in regulatory testing. A detailed comparison was made between traditional and alternative methods referenced in OECD TGs and Brazilian Pharmacopoeia monographs. Materials and Methods: A quantitative analysis evaluated the impact of CONCEA’s NRs (18/2014, 31/2016, 45/2019, and 56/2022) by comparing animal-based toxicological tests and species used with alternative methods recognized. Results and Discussion: Before the adoption of alternative methods, up to 534 animals could be used per batch. The recognition of 34 alternative methods through CONCEA’s NRs is projected to result in a 78% reduction in animals up to 2027. Conclusions: The implementation of CONCEA’s Normative Resolutions has significantly advanced the application of the 3Rs principles in Brazil, demonstrating a measurable reduction in animal use for regulatory safety testing. The study underscores the role of CONCEA’s NRs and international harmonization in promoting ethical and scientifically robust testing practices in Brazil. While progress is evident, the continued reliance on certain in vivo methods highlights the need for ongoing development, validation, and broader regulatory recognition of alternative approaches to ensure ethical and effective testing practices.