Clinical translation of findings from rare disease animal models to veterinary patients: practical reality or elusive dream

Animal research plays a critical role in developing disease treatments. Most studies are done in mice but larger species, phylogenetically closer to humans, are sometimes used. In the genomic age, numerous rare inherited diseases and attendant treatment challenges have been characterized. The US Food and Drug Administration and similar international agencies have enacted laws like the Orphan Drug Act for humans and the Minor Use and Minor Species Animal Health Act for animals to incentivize therapy development for these rare conditions. The remarkable curative potential of new cell and gene therapies (CGTs) has drawn attention to the drug approval process. Questions have been raised about whether animal findings adequately translate to humans. One justification for using animals in research has been the potential for them to ultimately benefit. This review highlights the bidirectional interplay of human and animal studies in keeping with the One Health - One Medicine concept. Examples of innovative drugs, sophisticated surgeries, and CGTs now being used in companion animals with rare diseases are provided. Related issues discussed in the paper include potential reasons for inconsistent translation of experimental animal findings in human clinical trials, barriers to using specialized treatments more broadly, ethical concerns associated with rare disease treatments, and prospects for developing alternatives that would benefit animals and reduce their use in research. The goal of this review is to encourage broader use of advanced therapies for rare companion animal diseases while helping to ensure ongoing research is done responsibly.