Joshua Stern, DVM, PhD, of North Carolina State University, has been studying a formulation of the medication rapamycin (sirolimus) that has been shown to forestall progressive ventricular thickening over a six-month period in cats with hypertrophic cardiomyopathy (HCM). Based in part upon these initial findings, the FDA recently granted conditional approval for the use of this drug in cats with HCM, and subjects are currently being enrolled for a follow-up 12-month clinical trial (the HALT HCM study).
Hypertrophic cardiomyopathy, a disease characterized by thickening of the ventricular walls of the heart, is the most common cause of cardiac disease in cats. This thickening makes it harder for the heart to pump blood efficiently to move oxygen to the tissues of the body.
There is no definitive cure for HCM yet, and treatment is currently focused on preventing or treating congestive heart failure and the development of clots that can form in the dilated atria of affected cats. The long-term prognosis for cats with HCM that develop heart failure and/or clots is, unfortunately, poor. Maine Coon Cats, Rag Dolls, Sphinx, Persians, and British Shorthairs are genetically predisposed to HCM.
Rapamycin appears to slow the progression of the muscle thickening and may even reverse it, if caught early. If this finding is validated by follow-up studies, this would represent a tremendous advance in our ability to treat a highly prevalent and impactful feline disease for which there is currently no cure.
Dr. Stern is working in collaboration with Dr. Sandra Tou and TriviumVet, an Irish animal health company that is funding this research and that holds the patent on this delayed-release formulation of rapamycin.
The goal of the HALT HCM study is to enroll 300 cats from 20 sites in the United States. Enrollees must be male or spayed female cats diagnosed with HCM that are not showing symptoms of their disease. They must be between 18 months and 15 years of age and otherwise healthy and able to take oral medications. Cats in the study will be evaluated five times over the 12-month study period, and all study-related testing and medications will be provided free of charge.
If you feel that your cat might qualify, let your veterinarian know. Only veterinary referrals are being accepted for this clinical trial. To enroll cases, your veterinarian can visit hcmincats.com.
