The drug, pramlintide, received U.S. regulatory approval in 2005 for the treatment of diabetes. Pramlintide is a synthetic version of a natural hormone made in the pancreas that signals satiety when a person has eaten enough and also slows the movement of food through the stomach.

Both processes suppress appetite, but the satiety signal reaching the brain has the stronger effect, says endocrinologist Christian Weyer of Amylin Pharmaceuticals in San Diego, which makes the drug and markets it as Symlin.

Weyer and other Amylin researchers teamed with scientists at Weill Cornell Medical College in New York City and Louisiana State University’s Pennington Biomedical Research Center in Baton Rouge for the new study. The scientists randomly assigned 411 obese volunteers to get a regimen of two or three injections daily for four months. One in seven received placebo shots while the rest got pramlintide in low, medium or high doses.

None of the volunteers had diabetes. The researchers counseled all of them to reduce their calorie intake and to boost their exercise. Each volunteer received a weight-loss manual and a digital pedometer.

After four months, the placebo-treated people had lost 6 pounds on average while the pramlintide group had lost 8 to 13 pounds, with the highest-dose volunteers losing the most. Roughly one-fourth of the placebo-treated people lost at least 5 percent of their body weight, compared with nearly half of those treated with pramlintide.

At the end of the full 12-month trial, people in the placebo group had regained most of their lost weight. Volunteers getting the medium-to-high doses of pramlintide had lost 14 to 18 pounds on average.

The main side effect of pramlintide is nausea, and 9 to 29 percent of volunteers, depending on dosages, complained of this symptom. As the dosage of the drug increased, more volunteers reported nausea. But Weyer says the nausea largely dissipated after a few weeks and wasn’t much different from nausea induced by other hormone-based drugs. “In essence, the body gets used to it,” he says.

Amylin is now giving obese volunteers a combination of pramlintide and a synthetic form of leptin, another satiety hormone the body makes. Leptin and pramlintide probably have a naturally occurring synergy that earlier tests suggested could lead to even greater weight loss, Weyer says. “In nature, they don’t act alone.” http://louisyjysheehan.blogspot.com

While the new findings are encouraging, it’s unlikely that pramlintide would work as a stand-alone intervention for obesity over a longer term, says George Blackburn, a physician and nutritionist at Harvard Medical School and Beth Israel Deaconess Medical Center in Boston. http://louisyjysheehan.blogspot.com But the Amylin researchers are on the right track in trying to combine it with a synthetic form of leptin, he says. The most promising trend in obesity research adds combinations of such potent medications to lifestyle changes that people can manage, he says.

“Getting weight off isn’t the challenge; keeping it off is,” he says. Medication provides an edge that raises an individual’s morale and motivation to comply with beneficial lifestyle changes, he says. Louis J. Sheehan