Molidustat oral suspension is also the first approval for cats under the FDA’s expanded conditional approval pathway.
The FDA has conditionally approved molidustat oral suspension (Varenzin-CA1; Elanco Animal Health) for the management of nonregenerative anemia in cats with chronic kidney disease (CKD). Molidustat oral suspension is the first FDA approval for a drug that helps to control nonregenerative anemia in cats.
A potentially fatal condition, nonregenerative anemia can be particularly impactful for cats with CKD due to issues pertaining to their bone marrow not being able to produce enough red blood cells to replace older or damaged red blood cells that the body naturally removes. In these cases, the result can be an inability for oxygen to be carried from the lungs to the rest of the cat’s body.
In cats, CKD is a disease that requires day-to-day management. Further, nonregenerative anemia is a complication that can occur in cats with CKD, and it can lead to death or euthanasia for affected cats due to their poor quality of life. Although CKD is frequently diagnosed in older cats, it is possible for cats to develop the disease at any age.
CKD can be triggered by the occurrence of other diseases, a malformation of the kidneys, bacterial or viral infections, kidney inflammation and associated damage (glomerulonephritis), cancers, or amyloidosis. Further, CKD can lead to nonregenerative anemia when the kidneys produce less erythropoietin, which is a hormone that helps to produce red blood cells in bone marrow.
Due to the lack of erythropoietin treatments approved for use in cats, the current treatments available for nonregenerative anemia in cats with CKD include blood transfusion, supplemental iron therapy, and erythropoietin replacement. With this conditional FDA approval, molidustat oral suspension will be the first approved drug for the treatment of this disease state in cats.
Molidustat oral suspension works by helping to increase the production of erythropoietin in the kidney. In turn, the increased production of this hormone stimulates bone marrow to increase production of red blood cells.
“[Molidustat oral suspension] 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 a press 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.”
Although the FDA has concluded that the drug is safe and provides a reasonable level of efficacy in cats, the approval was given on a conditional basis so that full efficacy data can be collected in a real-world setting. Further, the initial conditional approval will be valid for 1 year from the approval date, with the potential for 4 annual renewals. However, the FDA noted in the approval that the animal drug sponsor must show progress toward demonstrating substantial evidence of efficacy before a full approval can be given. Notably, if these conditions are not met by the 5-year mark, the FDA explained that the product can no longer be marketed for the use that was previously conditionally approved.
The FDA’s conditional approval authority was expanded in 2018 and was intended for treatments that address a serious or life-threatening disease or condition or an unmet animal or human health need for which the demonstration of efficacy is complex or particularly difficult. The FDA was granted the expanded conditional approval authority in the Animal Drug User Fee Act of 2018, with the program planned to sunset in 2028.
A reasonable expectation of efficacy for molidustat oral suspension had been established based on the results of a study conducted in 2 phases: The first phase was a multi-center, double-masked, randomized, placebo-controlled field efficacy and safety study, whereas the second phase was an unmasked, optional continuation of the first phase. Investigators enrolled 23 cats between the ages of 4 and 17 years from various breeds or breed mixes with CKD who were diagnosed with nonregenerative anemia.
Molidustat oral suspension is in the form of a liquid and is given by mouth to the cat once daily for no more than 28 days for the first treatment period. The treatment can be repeated as needed after a minimum of 7-day pause following the first treatment period. The drug is also only available by prescription from a licensed veterinarian.
The FDA noted that before providing a prescription for this drug to cat owners, veterinarians should discuss possible adverse effects (AEs), which include vomiting, increases in systolic blood pressure, and thromboembolism. Further, due to the ongoing nature of the conditional approval, the FDA encourages cat owners to report AEs from molidustat oral suspension to veterinarians for the purposes of ongoing data collection on efficacy and safety of the drug.
FDA Conditionally Approves First Drug for Anemia in Cats with Chronic Kidney Disease. FDA; May 1, 2023. Accessed May 1, 2021. https://www.fda.gov/news-events/press-announcements/fda-conditionally-approves-first-drug-anemia-cats-chronic-kidney-disease?utm_medium=email&utm_source=govdelivery