Scientific and Regulatory Policy Committee Points to Consider: Proposal and Recommendations to Reduce Euthanasia of Control Nonhuman Primates in Nonclinical Toxicity Studies.

The article focuses on a proposed study design to reduce the euthanasia of control nonhuman primates (NHPs) in Good Laboratory Practice (GLP) toxicity studies, aiming to align with the ethical "3Rs" principles (replace, reduce, refine) while maintaining scientific rigor. The proposal suggests retaining concurrent control animals during the in-life phase but limiting euthanasia to one control animal per sex per study, allowing non-euthanized controls to be returned to the colony for reuse, potentially reducing NHP use by 15–20%. It emphasizes the importance of concurrent control data for accurate interpretation of nonterminal endpoints and supports limited terminal data collection complemented by robust historical control databases and digital pathology tools. Ethical, regulatory, and operational considerations for animal reuse are discussed, along with a framework for prospective validation of the approach to ensure reliability in toxicity assessment.