Animal-Only Insulin Still In Infancy
Animal-only insulin is still relatively new, but manufacturers are working to make it more readily available.
The lack of a steady, reliable insulin supply for the veterinary industry used to be an obstacle to regulating pet diabetes, experts say.
Today, owner acceptance and education are additional hurdles, but manufacturers are working to simplify the management of the disease for clients and veterinarians.
Instead of relying solely on human insulin makers, several drug companies are catering to the veterinary industry and seeking Food and Drug Administration approval of their products. They also are investing in research to discover how to make diabetes maintenance more successful.
Lauren Boyd, DVM, Dipl. ACVIM, of Michigan Veterinary Specialists in Grand Rapids, Mich., says she uses as many types of insulin as she can in order to understand them.
“It’s a pain to switch insulin once the animal is regulated, but it is necessary sometimes when the product is discontinued or there’s a problem with it,” Dr. Boyd says.
She says she follows advancements in insulin offerings and in making diabetes more bearable for the pet and owner, but she has questions about one company’s pending introduction of a transdermal insulin delivery system.
Novartis Animal Health signed an agreement March 31 with Phosphagenics Ltd., an Australian pharmaceutical company, to develop the system for pets, saying the device would be more user-friendly than the traditional needle-injection method.
“We’re not at liberty to go into detail about the agreement or product but can say we’re excited about the benefits it can bring to owners of diabetic pets,” Novartis spokesman Mickey McDermott says. “We do not have a projected release date or additional information at this time.”
Boyd says such a device could be beneficial for clients who don’t see well, but she wonders about the delivery in long-haired pets and if clients accidentally absorb the insulin.
“I think anything that makes diabetes less difficult for owners will be a good thing,” she says.
When pet owners must administer insulin every 12 hours, problems can occur that throw an animal’s blood sugar into dangerous levels. Veterinarians say they work to educate owners and reduce the chance of disaster.
Issues With Insulin
Any vet who has practiced long enough has had a problem with insulin,” says Kurt Peterson, DVM, a technical veterinarian with Boehringer Ingelheim Vetmedica Inc. “Every insulin has been ineffective in certain patients and it’s largely because of the individual patient’s need and the lack of a match-up to the right insulin.”
Vetsulin Now Available for Qualified Patients
Intervet/Schering-Plough Animal Health was expected to begin offering a limited supply of Vetsulin (porcine insulin zinc suspension) on May 24 through its Vetsulin Critical-Need Program.
The U.S. Food and Drug Administration approved the program after veterinarians continued asking for the product.
In November, the FDA questioned the stability of Vetsulin and recommended that diabetic dogs and cats receiving Vetsulin be switched to other insulin products.
“In response to the Vetsulin product alert ... Intervet/Schering-Plough Animal Health has been working with the FDA to address an issue identified with our Vetsulin product,” Christopher Pappas Jr., DVM, the company’s director of technical services, wrote in a letter to veterinarians. “Since that time, we have recommended that pets be transitioned to other insulin products as we anticipated a limitation on supply and eventual supply depletion. During the process of transitioning pets to other insulin products, we heard from a number of veterinarians and pet owners who expressed significant concerns that specific dogs and cats cannot be effectively managed on an insulin product other than Vetsulin.
“After working with the FDA on this situation, Intervet can now offer a limited supply of Vetsulin to specific, critical-need pets, when in the veterinarian’s medical judgment these pets cannot be effectively managed on another insulin product. The availability of this supply will mean that truly critical-need patients can be maintained on Vetsulin.”
The FDA says veterinarians with qualified patients should contact the company’s technical services department at 800-224-5318. To enroll a patient, veterinarians must provide the rationale for why the patient cannot be effectively controlled using another insulin product. Click here for details about the program.
The FDA noted that because Vetsulin may have varying amounts of crystalline zinc insulin in the formulation, a delay in insulin action and an overall longer duration of insulin activity could occur.
Intervet/Schering-Plough Animal Health is working with the FDA to address the concerns.
A common issue, specialists say, is the lack of owner compliance—whether miscommunication in the household or ignorance about the importance of insulin regulation.
“If a cat decides to skip a meal on a particular day, a problem can occur,” Dr. Peterson says. “Hypoglycemia tends to be the biggest problem with cats, and owners aren’t always able to watch everything their pet does.”
Some veterinarians routinely recommend a diet change for diabetic pets while others urge minimizing or eliminating treats to help keep insulin levels in line.
“I almost always recommend a low carbohydrate diet for cats and no dry food at all,” Boyd says. “I tell clients not to free-feed, but that can sometimes get lost in translation. I’ve commonly found that clients shake insulin vials instead of rolling them in their hand; keep the same vial too long and it loses efficacy; or they mistakenly think someone else in the house already gave the injection—or didn’t give the injection and then the animal is overdosed.”
Complications like these are why companies are stepping in to try to reduce errors, they say. The key is to educate clients and then make the process as easy as possible.
“Diabetes isn’t a death sentence,” says Andrew McDowell, brand manager for Boehringer Ingelheim. “There’s not a cure, but there are effective ways to manage the disease, and helping clients understand where to set their expectations for maintenance is a starting point.”
Communication between the veterinarian and owner is essential, specialists say. Understanding how the disease affects the body, how to monitor the pet and how to detect side effects are essential.
“Veterinarians often provide owners with a brochure to explain the disease, but making the veterinary office a one-stop shop is crucial,” McDowell says. “Providing a diabetes care kit that includes a Sharps container, needles and syringes simplifies diabetes care.”
The industry suffered a blow in November when the FDA and Intervet/Schering-Plough Animal Health alerted veterinarians that varying amounts of crystalline zinc insulin made Vetsulin’s effectiveness unpredictable.
Veterinarians had been eager to incorporate the product—the first FDA-approved insulin for use in veterinary medicine—and took heat for its announced shortcomings.
“A lot of companies were vying for veterinarians to go with their insulin, and Vetsulin made a big push for business, then suddenly there’s a problem,” says Arnold Plotnick, DVM, Dipl. ACVIM, Dipl. ABVP, who owns Manhattan Cat Specialists in New York City. “Vets took the brunt of the problem with Vetsulin. Owners want to know why their pet now has to go through the regulation process with a new insulin.”
Boyd says she hears from veterinarians seeking recommendations for weaning patients off Vetsulin, but she says she’d still use the product should it come back to market.
“In Vetsulin’s absence, we are using the other intermediate acting insulin, NPH,” says Richard W. Nelson, DVM, Dipl. ACVIM, of the University of California, Davis. “Once Vetsulin returns, we will shift back to its use in dogs, primarily because there is a greater likelihood of problems with short duration of effect of NPH insulin in dogs than with Vetsulin in dogs.”
Types of Insulin
Since the need for insulin and the type used differs between dogs and cats, the course of maintenance will vary.
“The destructive process is rapid in dogs, and they are insulin-dependent at the time diabetes is diagnosed,” Dr. Nelson says. “Intermediate-acting insulins work best in dogs but need to be given twice a day in most dogs to gain control. Porcine lente insulin (Vetsulin, Caninsulin) is the most consistently effective insulin for controlling clinical signs and blood glucose concentrations in dogs and has been approved by the FDA for use in dogs.
“Lente insulin consists of approximately 30 percent amorphous insulin (rapid acting) and 70 percent insulin-zinc crystals (longer acting). Recently the percentages of amorphous and microcrystalline insulin shifted slightly toward less amorphous and more microcrystalline insulin.”
According to Nelson, cats’ pancreatic islets are destroyed at a slower rate than dogs’, which opens possibilities for treatments other than insulin and for possible remission of the diabetic state weeks to months after insulin treatment has been initiated.
“Cats tend to metabolize insulin very rapidly,” he says. “For this reason we tend to use longer-acting insulins. Intermediate-acting insulins like Vetsulin and NPH have a higher likelihood of problems with short duration of effect and inability to attain control of the diabetic state.
“The two long-acting insulins commonly used in cats are PZI and glargine. Both are effective and can have problems with too short or too long of a duration of effect when given twice a day. Both can induce diabetic remission. I use Vetsulin when I am having problems establishing diabetic control because of too long of a duration of effect of PZI, and glargine when given twice a day and too short of a duration of effect when switched to once-a-day therapy.”
Veterinarians say they make insulin decisions based on veterinary school exposure, continuing education, literature and what they’ve found most effective. The biggest indicator is what will most likely benefit a specific patient’s needs best.
“No two cats metabolize insulin the same,” Peterson says. “Cost can play a role in which insulin an owner can afford to try on their pet. ProZinc is a human recombinant insulin and helps maintain better glycemic control, which is helpful especially in dual-working households.”
Boehringer Ingelheim conducted the largest study of diabetic cats to date, evaluating 151 cats out of 176 initially enrolled. That helped the company earn FDA approval of ProZinc for use in cats in 2009.
“We were the first to bring an FDA-approved human recombinant to the veterinary market and we’re always looking for ways to improve,” McDowell says.
Intervet/Schering-Plough’s Vetsulin isn’t out of the picture. Company representatives say they hope to have a remedy as soon as possible.
“We are working to fix the problem,” spokeswoman Sharon Dilling says. “The amorphous or short-acting component may have a lower concentration due to the higher level of crystalline component. We cannot speculate how long Vetsulin will be unavailable once current supplies are exhausted.”
Practitioners and manufacturers alike say the more insulin options available to veterinarians, the better the treatment outcomes, given the vast difference in the needs of animals. They expect more veterinary-geared insulins to hit the veterinary market soon.
This article first appeared in the June 2010 issue of Veterinary Practice News. Click here to become a subscriber.