Veterinarians at the University of California, Davis, found that a cat’s DNA changes its response to a life-saving drug used to treat hypertrophic cardiomyopathy, or HCM, a heart disease that affects 1 in 7 cats. The study was published in the journal Nature Portfolio, Scientific Reports.
HCM causes a cat’s heart muscle to thicken. If the condition worsens, cats can form blood clots in their hearts that later break up and cause extreme pain, distress, and even sudden death. Clopidogrel, or Plavix®, is one of the most commonly prescribed drugs for preventing blood clots in cats with HCM.
“We kept seeing cats that were still clotting despite clopidogrel,” said correspondent writer Josh Stern, professor of veterinary cardiology and geneticist at the UC Davis School of Veterinary Medicine. This prompted Stern and the research team to begin research in the area and identify mutations in the drug pathway that appeared important. The data showed that nearly 20% of cats were resistant to clopidogrel therapy, which is widely used by doctors around the world.
“The aim of this study was to find out why some cats were not responding to clopidogrel therapy as expected and to guide us to a more effective prescription,” said Stern.
Simple genetic test
Researchers began a clinical study in cats with HCM. They first tested the cats’ ability to form blood clots. The cats’ owners administered clopidogrel for 14 days and the cats were retested. The researchers were then able to test whether genetic mutations they had identified within the drug pathway were responsible for reducing the drug’s effectiveness.
“The end result is the ability to use a simple genetic test to make an informed decision about which drug therapy is best for preventing blood clots in cats with HCM,” said Stern.
While tests like this are not yet commercially available, researchers hope that eventually veterinarians will be able to quickly test cats with HCM for these mutations while making prescribing decisions.
“We are very excited to approach this era in which personalized or precision medicine in animals can catch up with precision medicine in humans,” said co-author Ronald Li, assistant professor of emergency and intensive care veterinary medicine and coagulation researcher, whose laboratory performed much of the work the functional test of anticoagulant therapies. “Just as we cannot expect everyone to respond to medication in the same way, we cannot expect all cats to respond in the same way.”
Researchers hope that in the future, personalized medicine for cats would enable veterinarians to test kittens for a whole range of genetic variants that would help make medical decisions and treatments as they grow and need veterinary care.
Stern and the Cardiology Service of UC Davis Veterinary Medical Teaching Hospital continue to offer clinical trials to optimize the treatment of cats with HCM. The team is currently in a fully funded clinical trial of a drug that aims to be the first veterinary drug to reverse this devastating disease.
The research was carried out jointly by the Comparative Platelet and Neutrophil Physiology Laboratory and the Translational Cardiac Genetics and Pharmacogenomics Laboratory, both housed in the Center for Companion Animal Health. This study is also co-authored by Karen Vernau, Nghi Nguyen, Maureen Oldach, Eric Ontiveros, and Samantha Kovacs of the UC Davis School of Veterinary Medicine; Yu Ueda from North Carolina State University; and Michael Court of Washington State University. Funding was provided by the Morris Animal Foundation to support research and education for graduate students.