Can New Diet Pill Keep the Weight Off?

Feb. 14, 2006 -- If you take the diet drug Acomplia, you can keep off lost pounds only if you keep taking it, researchers say.

And those who stay on the drug keep their smaller waist, lower blood-fat levels, and higher good cholesterol levels.

If you don't cut your calories, Acomplia won't help you lose weight. But obese and overweight people who do eat less lost an average of 14 pounds if they were able to take Acomplia for one year. That's 10.5 pounds more than those who ate less and got an inactive placebo pill, reports F. Xavier Pi-Sunyer, MD, professor of medicine at Columbia University and chief of endocrinology at St. Luke's-Roosevelt Hospital, New York.

"I think it is exciting, because [Acomplia] has a new mechanism of action, and seems as effective [for weight loss] as any drug on the market," Pi-Sunyer tells WebMD. "[Acomplia] does a reasonable job of modest weight loss."

The results, first reported in 2004first reported in 2004, appear in the Feb. 15 issue of The Journal of the American Medical Association.

The FDA has not yet approved Acomplia, but is expected to act soon. In clinical trials, the drug has helped people lose weight. Obese people seem to have an overactive cannabinoid system. By partially shutting this system down, Acomplia helps people resist the craving for highly palatable food popularly known as 'the munchies.'

Acomplia also helps people quit smokingalso helps people quit smoking.

The Catch: Quit Drug, Regain Weight

Pi-Sunyer and colleagues enrolled more than 3,000 obese and overweight adults in the U.S. and Canada. They were told to eat a calorie-restricted diet and to exercise. For a month, everyone got inactive placebo pills -- and, on average, everyone lost a few pounds.

Then a third of the people got low-dose (5 milligrams per day) Acomplia, a third got higher-dose (20 milligrams per day) Acomplia, and a third got placebo pills. A year later, half of those on Acomplia were switched to placebo pills for the second year of the study. Neither the participants nor the researchers knew which people got Acomplia and which got placebo until the pill codes were broken at the end of the study.

The bottom line:

• Those getting low-dose Acomplia lost more weight than those on placebo, but the difference was small.
• Those getting higher-dose Acomplia lost an average of 10.5 pounds more than those on placebo did.
• People who took higher-dose Acomplia didn't just lose weight, their waistlines shrank by an average of 2.4 inches; they had higher levels of good HDL cholesterol, and lower blood-fat levels. This is likely to lower risk of heart disease.
• In the second year, people on higher-dose Acomplia did not lose more weight -- but they kept off the weight they'd lost.
• People who stopped taking Acomplia gained back the weight they had lost.

These findings are based on people who stayed in the study -- not those who dropped out. People taking Acomplia were no more or less likely to drop out of the study than those on placebo. And Pi-Sunyer, a veteran of many weight loss studies, says these studies always lose about a half of their participants -- usually people who had hoped to lose more weight than they did.