The U.S. Food and Drug Administration (FDA) has granted conditional approval for Felycin-CA1 (sirolimus delayed-release tablets) to manage ventricular hypertrophy in cats with subclinical hypertrophic cardiomyopathy (HCM). This reportedly marks the first approved treatment for any aspect of HCM in felines. The active ingredient, sirolimus, is an immunosuppressant in human transplant patients, but at the approved feline dose of 0.3 mg/kg weekly, it is not expected to be an immunosuppressant in cats. Available by veterinary prescription, Felycin-CA1 should not be used in feline patients with liver disease or diabetes. It comes in 0.4 mg, 1.2 mg, and 2.4 mg tablets. HCM is the most prevalent heart condition in cats, characterized by thickening of the left ventricle. Though its exact cause remains unclear, certain breeds, such as Maine Coons, Ragdolls, and Persians have a genetic predisposition. Cats in the subclinical stage exhibit heart wall thickening without visible symptoms, though the disease can progress to heart failure, arterial blockages, or sudden death. For more information on the recent conditional approval, visit the FDA website.
