Juvenile Rodents, Dogs, and NHPs in Safety Pharmacology Studies

Treating children with pharmaceuticals is recognized as being different than treating adults. Even treatment of children, from neonates to adolescents, is not a “one size fits all approach” due to physiological, anatomical, and biochemical changes that occur throughout the maturation process. Therefore, juvenile toxicity studies are based on a weight of evidence (WOE) approach and all study designs are “case by case.” The most common species for these studies are rodents, but dogs and nonhuman primates (NHPs) are the most common second species for adult toxicity testing and are also used for juvenile studies. The decision to use any species is based on adult toxicity findings, the class of drug, target organ systems, and the equivalent age in the test species to humans when the drug will be used. Data evaluation and reporting require careful planning to allow for appropriate analysis and interpretation of the data; this is aided by the availability of historical control data. Scientific staff familiar with the examination of samples and specimens from juvenile animals and with data evaluation and interpretation from developing animals is also important.