Use of nontraditional animals for evaluation of pharmaceutical products.

Although the International Conference on Harmonization Guideline ICH M3 indicates the use of nonrodents for some studies of pharmaceutical products, the specific nonrodent species is not specified. Dogs are used most frequently; however, there may be reasons why dogs are not the best model for a particular drug. Minipigs are being used increasingly for evaluation of toxicity, especially for dermally applied drugs, and for various efficacy models. Hamsters may be used for the evaluation of intraoral drugs and for carcinogenicity studies. Less commonly, pharmaceutical manufacturers may choose on their own to use marmosets, when a nonhuman primate is considered critical to evaluation, or to use ferrets for specific purposes. When nontraditional species are used, there may be less historical information available and unique issues of their care, and differences in physiology and anatomy and susceptibility to infection need to be understood. Nonmammalian test species, such as zebrafish and Caenorhabditis elegans may be used by drug sponsors in screening assays, but are not yet ready for use in pivotal toxicology studies because of the difficulty in extrapolating to mammalian species. Use of nontraditional animal species may be proposed by a drug sponsor to a reviewing division with supporting data and reasons for using a particular species.