Clinical veterinarian’s perspective of non-human primate (NHP) use in drug safety studies

Abstract

Owing to their size, cost, and availability, the cynomolgus macaque (Macaca fascicularis) has surpassed the rhesus macaque in its use as a non-human primate preclinical model for drug safety studies. There are three major regions where cynomolgus macaques are bred: China, Southeast Asia, and the island of Mauritius. Country of origin of the macaque is important, as disease status and background disease incidence in non-human primates from each of these sites can differ. Once a source of macaque has been decided, careful monitoring of the animal during breeding and by the importing vendor while the animals are in quarantine is important. During vendor quarantine, the animals should be monitored and evaluated for disease, response to tuberculosis testing, retroviral status, and both ecto- and endoparasites. After animals arrive at the test facility, additional quarantine and acclimation are important to ascertain health status further and to reduce stress on the animals, thereby providing a better research model. The type of caging, food, water, and enrichment should be carefully selected to best suit the needs of the study while working within Federal Regulations (i.e., Animal Welfare Act and Good Laboratory Practices). Careful prescreening by performing tests (such as physical, neurologic, and ophthalmologic examinations), complete blood count, biochemical profile, urinanalysis, electrocardiograms, and pulse oximetry is important when selecting the most appropriate animals for the study. After the in-life portion of the study begins, animals that present with clinical signs should be examined and an appropriate treatment course begun while maintaining study objectives. As many commonly used medications have immunomodulatory effects, having an understanding of the mechanism of action of test articles will aid in the appropriate choice of treatment of study animals. A tiered approach to the treatment of these animals is a conservative and usually acceptable approach.