So far, CYT009-GhrQb is the first true "fat vaccine" to enter human clinical trials. But it's not the only treatment designed to combat obesity. Since the Food and Drug Administration removed the diet drug combo called "fen-phen" from the market in 1997 because of potentially deadly heart-valve problems, the agency has approved two obesity drugs, Xenical and Meridia. Both are currently available by prescription (read more about them in How Diet Pills Work). Several other anti-obesity drugs are further back in the research and development pipeline:
Acomplia is sometimes referred to as the "munchies drug," because it acts on the brain in the opposite way of marijuana. Scientists developed the drug after noticing that people who smoked marijuana often experienced food cravings, or "the munchies." These food cravings occur when substances in marijuana called cannabinoids act on cannabinoid receptors in the brain. Scientists figured out that by blocking those receptors, they could control food cravings. In a study of 1,500 obese or overweight people, participants who took 20 milligrams of Acomplia for a year and cut 600 calories out of their diet lost about 14 pounds, compared with only 4 pounds among people who took a placebo. The participants also lowered their cholesterol, triglycerides (fats that circulate in the bloodstream), and insulin resistance (a condition in which the body does not effectively take glucose, or sugar, into the cells). Although Acomplia is not yet available in the United States, its manufacturer, French pharmaceutical company Sanofi-Aventis, is applying for an FDA license to market the drug here by 2006.
British researchers are working on an anti-fat injection containing the hormone oxyntomodulin, which is naturally found in the small intestine and lets the brain know that the body is full. Researchers believe that injections of this hormone could help obese individuals eat less. In one small study, people who took oxyntomodulin lost about 4 ½ pounds more than people who took a placebo. Researchers say they will need to conduct more studies to confirm whether this treatment is effective. Although oxyntomodulin is sometimes called a "fat vaccine" in the media, it is not a true vaccine because it does not involve the immune system.
The German-based Noxxon Pharma is working on another drug called Spiegemler that, like the CYT009-GhrQb vaccine, targets ghrelin to battle obesity. But unlike the vaccine, Spiegelmer does not involve the immune system. Instead, it binds to and neutralizes ghrelin in the blood to control appetite. In a seven-day study, mice that were given the drug lost more weight than a control group.
Despite the many promising new anti-obesity drugs on the horizon, experts say there probably won't be any one "magic pill" for weight loss anytime soon. For right now, the best way to lose weight and keep it off is probably through old-fashioned diet and exercise.
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