FDA grants first conditional approval to control seizures in dogs

Today, the U.S. Food and Drug Administration granted the first conditional approval under its expanded authority to KBroVet-CA1 (potassium bromide chewable tablets) to control seizures in dogs with idiopathic epilepsy. Idiopathic epilepsy is a type of seizure disorder without a known cause. KBroVet-CA1 works by stabilizing neurons in the central nervous system to reduce the likelihood of having a seizure.

Congress granted the FDA a limited expansion of the conditional approval pathway for certain new animal drugs under the 2018 reauthorization of the FDA’s Animal Drug User Fee Act (ADUFA) program. Conditional approval allows an animal drug sponsor to legally market its product after demonstrating that the drug is safe and manufactured in accordance with full approval standards, and that there is a reasonable expectation of effectiveness for use.

Prior to this expansion, the FDA’s conditional approval of new animal drugs had been limited to drugs for use in minor species (those other than horses, dogs, cats, cattle, pigs, turkeys, and chickens) or for diseases in the major species that occur infrequently or in limited geographic areas and in only a small number of animals annually. The expanded authority allows for conditional approval of treatment options that are intended to address a serious or life-threatening disease or condition, or an unmet health need, but for which demonstrating effectiveness would require complex or particularly difficult studies.

KBro-Vet-CA1 meets the criteria of conditional approval under the expanded authority, as there is currently no animal drug approved and marketed in the U.S. for the treatment of idiopathic epilepsy in dogs, a serious or life-threatening condition that affects approximately 5% of the canine population.

The initial conditional approval is valid for one year with the potential for four annual renewals. During this time, the animal drug sponsor must demonstrate that it is actively working toward collecting the remaining effectiveness data needed to achieve full approval. The animal drug sponsor must attain full approval within five years after receiving conditional approval, or it will no longer be in effect.

Potassium bromide has been used to control seizure disorders in dogs for an extensive period of time, however, prior to FDA being granted the new authority, no animal drug sponsor had applied for approval. To help establish the safety of potassium bromide and meet the agency’s commitment to reduce, replace and refine the use of animals in research, the FDA took an innovative approach that enabled the company to meet the safety standard for approval without performing prospective animal studies. Instead, the sponsor of KBroVet-CA1 was able to use safety data from a Public Master File that the FDA created after conducting a review of more than 50 years of published literature on the use of potassium bromide in dogs. The FDA published this literature review in 2012 in the Journal of the American Veterinary Medical Association.

“We are pleased to see animal drug sponsors respond to the expanded conditional approval authority by bringing forward applications to treat serious, life-threatening diseases for which there are no approved therapies available,” said Steven M. Solomon, D.V.M., M.P.H., director of the FDA’s Center for Veterinary Medicine. “We are especially encouraged that the sponsor could utilize the data that the FDA provided in the Public Master File to avoid the need to perform animal testing for the development of this product.”

Based on the reviewed articles, the most common adverse drug events associated with potassium bromide were found in the neurologic (including behavioral changes), gastrointestinal (including inflammation of the pancreas), reproductive, endocrine, dermatologic and respiratory systems. Some dogs also had increased thirst and urination. Dogs with decreased kidney function may be at greater risk for bromide intoxication (overdose). The reasonable expectation of effectiveness of KBroVet-CA1 was established in a retrospective study of medical records of 51 client-owned dogs diagnosed with idiopathic epilepsy that were treated with only potassium bromide at the same dose for at least 60 days to control their seizures.

KBroVet-CA1 is orally administered daily for the control of seizures associated with idiopathic epilepsy in dogs. It is available only by prescription due to the professional veterinary expertise required to diagnose idiopathic epilepsy and to monitor safe use of the product, including treatment of any adverse reactions. It is important for owners of dogs with idiopathic epilepsy to work closely with their veterinarians to monitor clinical signs in order to control potential seizures that may result from bromide intoxication. It is also important to avoid abrupt diet changes in dogs receiving potassium bromide because it could either compromise seizure control or raise safety concerns. Signs of severe bromide intoxication can include depression, behavioral changes, ataxia, hind limb paresis, mydriasis, stupor and coma.

The FDA granted conditional approval of KBroVet-CA1 to Pegasus Laboratories Inc.