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Flowers? Some kind of ceremony? A package of small mammals? It’s tough to know how to thank a Gila monster, but a new drug made from of one of the reptile’s hormones is giving diabetics a lot to be grateful for.
At the School of Medicine, chief of endocrinology John Buse just completed a study of the drug with patients diagnosed with type 2 diabetes. And the results are exciting — after three years on exenatide, most patients had healthy sustained glucose levels and progressive weight loss (averaging around 11 pounds), a feat for many diabetics.
Weight gain and being overweight is a pervasive problem among these patients, Buse said, and insulin injections — currently the most commonly prescribed medication for the diabetes — can cause more weight gain, which can, in turn, worsen the disease.
Exenatide, sold commercially as Byetta, received FDA approval two years ago. Drug makers Eli Lilly and Amylin Pharmaceuticals haven’t even begun marketing it yet, but among in-the-know type 2 diabetics, the drug has become wildly popular, helping patients lose weight who were finding it nearly impossible with their other medications — even with proper diet and exercise.
So why Gila monsters? John Eng, an endocrinologist at the Bronx Veterans Affairs Medical Center in New York City, was looking at studies of people who developed pancreatitis after being bitten by venomous animals. Eng wanted to find the connection, so he ordered a slew of animal venoms, including that of the Gila monster, and started looking for ones that affected the pancreas (the organ that controls blood sugar by releasing insulin).
He found that the Gila monster, a large, venomous lizard native to the southwestern United States and northwestern Mexico, secretes a hormone in its saliva called exendin-4. This hormone, which aids digestion in the lizard, is similar to a human digestive hormone called GLP-1 (glucagon-like peptide-1 analog), which increases insulin production when a person has high blood sugar. GLP-1 also slows the emptying of the stomach, which reduces appetite and makes people feel full, said Buse.
GLP-1 had been on the table as a potential diabetes treatment, Buse says, but its rapid breakdown in the body made it hard to produce as a convenient drug. But exendin-4 has a much longer half-life, and scientists can create large amounts of it synthetically in the lab. And that’s what the new drug is made of — synthetic exendin-4.
Patients who take Byetta have to self-inject twice a day and usually have to stay on the medication even after they reach a healthy weight and lower their blood sugar, Buse said. “If they stop the drug,” he said, “the assumption is that they’ll slide back to where they were before.”
Buse presented his findings three weeks ago at the annual scientific sessions of the American Diabetes Association, of which he will become president in September. The study’s co-authors are Leigh MacConell, Anthony H. Stonehouse, Xuesong Guan, James K. Malone, Ted E. Okerson, David G. Maggs, and Dennis D. Kim. All of the co-authors work for Amylin Pharmaceuticals except Malone, who works for Eli Lilly and Company. Amylin has a global agreement with Eli Lilly and Company to collaborate on the development and commercialization of exenatide. Funding for this study was provided by Amylin and Eli Lilly and Company.
Editor: Neil Caudle
Writer: Colie Hoffman