Module232025

07/05/2025

One of the hardest aspects in designing a JAS is choosing the most appropriate age of animals. The age of animals at dosing initiation should developmentally correspond to the youngest intended patient age and will depend on a human-to-animal comparison of developmental periods of organ system(s) of toxicological concern. As comparative organ system correlations are not aligned for each organ across species, priority should be given to any target organ/system of potential concern or to particularly vulnerable developing systems in the intended patient population.

The Organisation for Professionals in Regulatory Affairs

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The ICH S11 does include an overview of age-dependent development of organ systems by species. However, the tables were based on a review of knowledge up to 2020 and are not comprehensive. Species-specific and/or organ system reviews in the literature can provide additional detail and should be consulted for each specific situation. Factors such as strain, breeding, and animal supplier can impact age dependent development and should also be considered.

The Organisation for Professionals in Regulatory Affairs

28