FDA conditionally approves first drug for anemia in cats

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The FDA conditionally approved Varenzin-CA1 (molidustat oral suspension), the first drug for the control of nonregenerative anemia associated with chronic kidney disease (CKD) in cats. According to a release from the FDA, nonregenerative anemia can be a fatal condition because the cat's bone marrow is not able to produce enough red blood cells to replace the older or damaged red blood cells that are naturally removed from the blood, resulting in the inability for oxygen to be carried from the lungs throughout the body.¹

CKD is a disease that requires day-to-day management in cats, and nonregenerative anemia is a complication that often contributes to death or euthanasia of affected cats due to poor quality of life. Cats can develop CKD at any age, but it is frequently diagnosed in older cats.¹ The FDA stated that CKD, “can be triggered by other diseases or malformation of the kidneys, bacterial or viral infections, kidney inflammation and associated damage (glomerulonephritis), cancers, or a build-up of protein in the kidney (amyloidosis).”¹ Cats with CKD develop nonregenerative anemia when their kidneys produce less of a hormone called erythropoietin, which helps the bone marrow produce red blood cells.

Current treatments available for nonregenerative anemia in cats with CKD include blood transfusion, supplemental iron therapy, and erythropoietin replacement. There are no erythropoietin treatments approved for use in cats, however, Varenzin-CA1 helps increase production of erythropoietin in the kidney, which in turn stimulates the bone marrow to produce more red blood cells.¹

"Varenzin-CA1 is the first drug to receive conditional approval for use in cats, providing access to a novel medicine for our feline companions suffering from nonregenerative anemia due to CKD," said Tracey Forfa, director of the FDA's Center for Veterinary Medicine, in the release. "Additionally, this is the first drug for cats under expanded conditional approval, a pathway to the marketplace that encourages development of innovative treatments and increases the options for treating animals with uncommon conditions, serious or life-threatening diseases, or diseases without existing or adequate therapies."¹

To receive conditional approval, Varenzin-CA1 was evaluated in a study conducted in 2 phases. The first phase was a multi-center, double-masked, randomized, placebo-controlled field effectiveness and safety study. The second phase was an unmasked, optional continuation of the field study. Both phases in the study enrolled 23 cats from 4 to 17 years of age from various breeds and mixes who were diagnosed with nonregenerative anemia associated with CKD.

Varenzin-CA1 is a liquid given by mouth to the cat once daily for up to 28 days. The FDA recommendation is that treatment may be repeated as needed after a minimum 7-day pause. Varenzin-CA1 is available only by prescription from a licensed veterinarian given that professional expertise is required to properly diagnose CKD and nonregenerative anemia in cats and before prescribing the drug, veterinarians should advise cat owners about possible side effects, which include:¹

• vomiting
• increases in systolic blood pressure
• thromboembolism (blood clots)

Reference

FDA conditionally approves first drug for anemia in cats with chronic kidney disease. News release. The US Food and Drug Administration. Published May 1, 2023. Accessed May 2, 2023. https://prnmedia.prnewswire.com/news-releases/fda-conditionally-approves-first-drug-for-anemia-in-cats-with-chronic-kidney-disease-301812195.html