Drugs Old and New May Fight Diabetes

Anti-malaria drug cut disease risk, and new drugs helped diabetics lose weight

TUESDAY, July 10, 2007 (HealthDay News) -- An old drug used in a novel way and a new class of drugs may both offer promise for preventing and treating type 2 diabetes, new research suggests.

In one study, scientists found that a medication used to prevent malaria and treat rheumatoid arthritis and lupus may also help prevent the development of diabetes. A second study detailed the latest research done on a new FDA-approved class of medications called incretin therapy for the treatment of type 2 diabetes. Both reports appear in the July 11 issue of the Journal of American Medical Association.

Almost 21 million Americans have diabetes, and most of them have type 2 diabetes, according to the National Institute of Diabetes and Digestive and Kidney Diseases. In type 2 diabetes, the body stops producing enough insulin or no longer uses insulin effectively, which means blood sugar levels may rise too high.

The first study examined the effect of a very old medication, hydroxychloroquine, on the development of diabetes.

"This medication has been around for 50 years, it's available generically and has been used as a treatment and preventative for malaria, and a treatment for lupus, rheumatoid arthritis and other rheumatic diseases," noted Dr. Mary Chester Wasko, an associate professor of medicine at the University of Pittsburgh.

Wasko said this drug first piqued her interest when one of her patients developed low blood sugar while taking hydroxychloroquine. Additionally, she said, there isn't an excess of diabetes among people with rheumatoid arthritis (RA), which would be expected because many people with RA have diabetes risk factors, such as a sedentary lifestyle.

To see if there was an association between hydroxychloroquine and diabetes, Wasko and her colleagues examined an extensive database of almost 5,000 people with rheumatoid arthritis. The database included more than 20 years of follow-up, and the participants reported their health condition every six months. Just over 1,800 people included in the database had taken hydroxychloroquine to treat their rheumatoid arthritis.

During the 21.5 year period covered by the database, 54 people taking hydroxychloroquine and 171 who had never taken the drug developed diabetes. That means taking hydroxychloroquine conferred a 38 percent diabetes risk reduction. And, the researchers found that the longer a person took hydroxychloroquine, the less likely they were to develop diabetes. Those who took the drug for longer than four years had a 77 percent reduced risk of diabetes.

Wasko said the researchers don't know how hydroxychloroquine reduces the risk of diabetes, and that further research is necessary.

"If it is to have a potential for prevention, we must understand its mechanism of action. Certainly, my hope for this relatively inexpensive and safe drug is that it may have a future role in the prevention of diabetes in people with a high risk, and these preliminary findings may be a first step in that direction," she said.

"This is an interesting study," said Dr. Stuart Weiss, an endocrinologist at New York University Medical Center. But there's no information on how the drug might alter the development of diabetes and, he added, "I think we already have reasonable diabetes medications, although in the current atmosphere of cost control, we may have to think more about using less expensive drugs."

The second study included a review of 29 previously completed studies on incretin therapy for treating type 2 diabetes. Incretin is a hormone, secreted by the gut, which signals the pancreas to produce more insulin in response to eating. It's only recently that scientists have begun to better understand this hormone, according to study author Dr. Anastassios Pittas.

Two medications based on this new knowledge and approved by the U.S. Food and Drug Administration include an injectable synthetic form of incretin and an oral medication, marketed under the brand name Januvia, that inhibits the breakdown of incretin, thereby increasing the levels of the hormone, explained Pittas, an assistant professor of medicine at Tufts-New England Medical Center in Boston.

Both forms of incretin therapy worked similarly to other blood-sugar lowering medications but were not as effective as another diabetes medication, metformin.

One benefit found with the injectable form was weight loss, and Pittas added that this medication is now being looked at in clinical trials as a weight-loss drug. The oral incretin therapy didn't cause weight loss, but it also didn't cause weight gain -- a problem that's common with some diabetes medications.

The majority of the trials lasted less than 30 weeks, so long-term effects are still unknown, though Pittas said the drugs appear to have relatively few side effects, except for nausea and vomiting, and a slightly increased risk of infections.

"Incretin therapy is a welcome addition to what we already have. I wouldn't necessarily jump into using them, because the cost is five to 10 times more expensive than older, more established medications," said Pittas.

More information

To learn more about diabetes, visit the National Diabetes Information Clearinghouse.

SOURCES: Anastassios Pittas, M.D., M.Sc., assistant professor, medicine, division of endocrinology, diabetes and metabolism, Tufts-New England Medcal Center, Boston; Mary Chester Wasko, M.D., M.Sc., associate professor, medicine, division of rheumatology and clinical immunology, University of Pittsburgh; Stuart Weiss, M.D., endocrinologist, New York University Medical Center, and clinical assistant professor, New York University School of Medicine; July 11, 2007, Journal of the American Medical Association
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