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Canker sore drug reverses weight gain in mice

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When screening nearly 150,000 drugs for metabolic properties in an attempt to find an anti-obesity therapy, scientists stumbled upon an unlikely candidate--a drug used to treat canker sores.

Also called mouth ulcers, canker sores are benign and noncontagious lesions. A team of scientists, led by researchers at the La Jolla, CA-based Salk Institute for Biological Studies, found that amlexanox--used in the U.S. as a topical paste to combat mouth ulcers and in Japan in another formulation to treat asthma--prevented weight gain in mice. The drug has been on the market for more than 15 years.

"This [drug] is mostly used to treat canker sores, which are inflammatory events, and that led to a growing interest that maybe this is working as an anti-inflammatory," Ronald Evans, a professor in Salk's Gene Expression Laboratory and lead researcher in the institute's new Helmsley Center for Genomic Medicine, explained to FierceBiotechResearch.

Evans, along with researchers from the University of Michigan and the University of California, San Diego, fed mice a high-calorie diet and when the animals became obese, they were given an injectable form of amlexanox. When compared to the control mice, the animals given amlexanox lost weight, despite eating the same diet. The drug also reduced their body fat and reversed Type 2 diabetes. When the mice were taken off the drug, though, their symptoms were reversed, and they gained back the weight they had lost while on it--which could be a concern in human studies. The findings were published recently in Nature Medicine.

Some weight-loss drugs act as an appetite suppressant, like Amylin Pharmaceuticals' ($AMLN) Byetta. Amlexanox increased metabolism in mice by inhibiting two genes--IKKE and TBK1--which appear to play an important role in maintaining metabolic balance.

Evans said that the underlying problem with obesity is that, as you put on weight, the body becomes inflamed and eventually gets to a state of chronic inflammation. This explains why it's so difficult for obese people to lose a substantial amount of weight even if they change their diet and exercise more.

Researchers are hopeful that they will be able to start clinical trials with amlexanox later this year. Evans noted that there's even the possibility that amlexanox could be used to treat other inflammatory-based chronic disease.

"Now that we're on to this idea, we have a way of evaluating other drugs or new drugs that might have related activities," he said.

- read the press release
- get the research abstract

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