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The Annual Meeting of the Obesity Society (Boston, Massachusetts, October 20-24)

Published: 2/28/07

The Obesity Society's annual meeting has long been our favorite place to catch up on the basic science research behind this critical problem. While the FDA has not approved a new obesity drug since 1999, we came away feeling optimistic that promising new treatments are on the horizon.

society makes both weight loss and weight maintenance extremely difficult.

In our current "obesogenic" environment, junk food is invariably cheaper than healthy food and people must schedule time to exercise because physical activity is so absent from our daily routines. Poor neighborhoods often lack grocery stores or safe places to exercise. Even when people do lose weight, both biological mechanisms and the pull of environmental lures makes weight difficult to keep off.

low efficacy and reimbursement hamper use of current obesity drugs.

Two prescription drugs are currently available for long-term weight management treatment: orlistat (Xenical) and sibutramine (Meridia). Both drugs cause about 5% loss of total body weight, which is enough to improve several medical measures of metabolic health but which, for many people, would not be very noticeable. In addition, the side effects can be quite unpleasant or downright worrisome: Xenical causes problems with oily stools and Meridia tends to raise blood pressure. Because obesity continues to be viewed as a lifestyle choice rather than as a medical condition, few insurers cover these drugs.

bariatric surgery is effective but invasive and expensive.

Surprisingly, neither physical restriction of the stomach's size nor mal-absorption of nutrients is the main cause of weight loss when people get gastric bypass surgery. While both do play a role in short-term weight loss, the most important change that occurs in people who get gastric bypass surgery is in the way their small intestines secrete gut hormones (a.k.a. incretins) in response to food. In the short term, these hormonal changes can reverse obesity-associated type 2 diabetes, even before patients begin losing weight! In the long term, surgery patients will feel full more easily and eat less, allowing them to keep off the weight in the initial months after surgery.

the obesity pipeline is rich in neuroendocrine therapies.

Rimonabant, a drug that reduces weight that is currently under review by the FDA, acts on the central nervous system to decrease appetite. Rimonabant seems slightly more effective than Xenical and Meridia, but side effect concerns include depression and anxiety - if you are interested in taking any new medicine, of course, always ask your doctor or healthcare team about side effects. Further down the road, but perhaps more promising, is the possibility of using incretin therapeutics to treat obesity. As we discussed in our previous issue, both Byetta and Symlin are incretin hormones that cause weight loss when used for diabetes. Amylin, the maker of both drugs, is researching combinations of Symlin and another compound, leptin, as well as other hormones involved in appetite regulation. Results in rats have been promising, and although human immune systems are very different from those of rats, we look forward to seeing data on how these combinations work in humans.

What do you think?