New oral diabetes drug for cats requires careful case selection, says Emily Singler
Introduction
Last month, the Food and Drug Administration (FDA) announced the approval of Bexacat, the first oral medication for the treatment of diabetes in cats (oral feline diabetes medication). Bexagliflozin, the active ingredient in bexacat, is a sodium-glucose cotransporter-2 inhibitor that prevents renal glucose reabsorption, thereby causing excess blood sugar to be excreted in the urine.
It is approved for use as an oral feline diabetes medication in otherwise healthy cats with diabetes mellitus that have not previously been treated with insulin. It is administered as a tablet that can be crushed and mixed into food once daily and carries a much lower risk of dangerous hypoglycemia compared to insulin administration.
On January 13, the FDA issued a letter to veterinarians highlighting important safety considerations when using this medication (oral diabetes medication for cats).
The intricacies of diabetes in cats
Renee Rucinsky, DVM, DABVP(F), president-elect of the American Board of Veterinary Practitioners, provides insight into the appropriate use of bexacat. She points out that many cat owners are afraid of injecting their cats with insulin. Cost can also be a factor, especially since the price of insulin has skyrocketed. Other obstacles that make it difficult for cat owners to choose insulin treatment include proper dosage, adherence to schedule, and the risk of life-threatening hypoglycemia.
Veterinarians and veterinary teams also face challenges: they must find sufficient time to adequately train cat owners and carefully consider the specifics of diabetes in cats, as each case is very different.
For these reasons, the idea of a once-daily oral medication that does not pose as much risk of hypoglycemia can be very tempting. However, an appropriate selection of cases is essential," warns Rucinsky.
Benefits of Bexacat as an Oral Diabetes Medication for Cats
While cats and dogs cannot be strictly divided into insulin dependent or insulin resistant categories, Rucinsky points out that diabetic cats are more likely to be insulin resistant. In these cats, administration of exogenous insulin may not be necessary or helpful. Bexacat improves blood sugar control without the need for additional insulin. Field studies with bexacat have shown that the drug improves blood sugar control in diabetic cats by more than 80%.
Bexagliflozin has also been studied and is currently being developed for the treatment of type 2 diabetes in humans. Clinical trials have found not only improved blood sugar control, but also improved weight loss and a reduction in high blood pressure in type 2 diabetics. Non-diabetics with chronic kidney disease and certain forms of heart failure have also experienced health benefits from taking bexagliflozin. While weight loss in humans is a possible benefit of this drug, the Bexacat package insert lists weight gain as a possible effect of treatment in cats. No cause is given for weight gain in cats, but it may be that they are regaining the weight they lost before their diabetes was well controlled.
When insulin is the safer choice
When deciding whether to use this medicine for a patient, Elanco (the manufacturer) lists warnings that must be carefully considered. Bexacat should only be used in cats that have been diagnosed with diabetes mellitus, that show no other signs of the disease and that have never been treated with insulin.
Rucinsky explains that this is very important because cats can also develop diabetic ketoacidosis (DKA), a potentially fatal complication, while taking bexacat. If a cat is sick at the time of diagnosis, it is at higher risk of developing DKA, and insulin is a "much safer choice," advises Rucinsky.
Signs to Avoid Bexacate
Signs of illness that would justify avoiding bexacat include any evidence of "other active systemic disease, including kidney, liver or pancreatic disease, or ongoing DKA" as well as:
- Dehydration
- lethargy
- anorexia
- weakness
- Difficulty walking or standing
Who Shouldn't Get Bexacat?
Newly diagnosed geriatric diabetic cats around 13 years old or older, and especially those who were not overweight before diagnosis, are more likely to be insulin dependent and have comorbidities, explains Rucinsky. For this reason, they are probably not good candidates for treatment with bexacat.
Cats that have already been treated with insulin are also not candidates for this medication. "In these cats," explains Rucinsky, "discontinuation of insulin therapy can lead to DKA because the cat may not be able to produce enough endogenous insulin."
The danger in looking for signs of DKA in cats receiving bexacat is that they may have euglycemic DKA, which can complicate diagnosis and treatment. "Treating this problem may be uncharted territory, and veterinarians must be prepared to learn the intricacies of treating potentially very sick cats whose lab results do not look what they are normally used to.
How should Bexacat be used?
Both Rucinsky and Elanco point out that there is no way to know in advance which cats are insulin resistant and which are insulin dependent. The best way to select good candidates for bexacat is to carefully monitor for signs of illness, evaluate each cat's history of previous insulin use, and advise owners of the risks.
Rucinsky points out that cats that have just been diagnosed with diabetes are more likely to still be able to produce enough insulin to prevent DKA. However, all cats receiving bexacat should have their serum beta-hydroxybutyrate (BHB) levels checked using an in-house ketone meter 3 to 5 days after starting therapy. When levels are elevated, DKA is more likely.
Additionally, cats should be closely monitored for clinical signs suggestive of the development of DKA, even if their blood sugar remains within normal limits. Cats that develop signs of DKA or other illness should stop taking bexacat immediately and seek veterinary care, according to Elanco.
Although she is cautious about choosing cases, Rucinsky is enthusiastic about Bexacat and the benefits it can provide cats and their owners. She hopes this medication, coupled with careful patient assessment and customer education, will open the doors to treatment for cats who might not otherwise receive it.
Further reading
Bexacat Customer Information Sheet:
https://animaldrugsatfda.fda.gov/adafda/app/search/public/document/downloadLabeling/1318
AAHA Diabetes Management Guidelines:
https://www.aaha.org/aaha-guidelines/diabetes-management/diabetes-management-home/
Use of bexagliflozin in humans:
https://pubmed.ncbi.nlm.nih.gov/34292100/
More articles on oral diabetes medication for cats:
Emily Singler, VMD, graduated from Penn State University in 2001 and the University of Pennsylvania School of Veterinary Medicine in 2005. She has worked in animal shelters, in private practice and as an assistant veterinarian. She currently works as a veterinary author and consultant with her own blog www.vetmedbaby.com. She also writes a monthly column for NEWStat focusing on One Health and the relationship between humans and animals.
If you have any further questions, we are you at any time. We will keep you up to date when we have received approval as an oral diabetes medication for cats in Europe.