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Weight-Loss Drug Shows Further Promise

April 19, 2005

Results for rimonabant trial parallel those of American study

HealthDay News — A major European trial of a drug that helps people lose weight, slim their waistline and reduce risk factors for heart disease has achieved the same promising results as a similar North American trial, researchers report.

The drug, rimonabant, could be on the market in both Europe and the United States by the end of the year, said Dr. Luc Van Gaal, professor of medicine at University Hospital Antwerp in Belgium, and lead author of a report on the trial in the April 16 issue of the journal The Lancet.

The drug company Sanofi-Synthelabo, which plans to market the drug as Accomplia, did not respond to a request about its plans for getting regulatory approval.

Rimonabant acts by blocking receptors in the endocannabinoid system, one of the body’s pleasure centers — the same class of centers affected by marijuana. The drug offers a new approach to the problem of obesity, which has reached epidemic proportions in both Europe, where more than 50 percent of adults are classified as overweight, and the United States, where the proportion is 60 percent. Obesity is a major risk factor for heart attack, stroke and other cardiovascular problems.

The trial reported in The Lancet included 1,507 people, mostly Europeans but a few from the United States. They had a body mass index of 30 kilograms per meter squared or greater, which classified them as overweight. They also had high blood levels of fats, high blood pressure, or both. Some took 5 milligrams of rimonabant a day, some took 20 milligrams a day and others took a placebo, an inactive substance

More than 67 percent of those who took the 20-milligram dose of rimonabant for a full year had a weight loss of at least 5 percent. And 39 percent achieved weight loss of 10 percent or greater, about 20 pounds. Their waist size shrank by an average of 1.5 inches, and there was a substantial reduction in such risk factors as high cholesterol levels. Those taking the 5-milligram daily dose for the full year had lesser weight loss but did better than those on a placebo.

About a third of the participants dropped out of the study because of side effects, including mood disorders, nausea, vomiting, diarrhea, and headache.

The results virtually mirrored those of an even-larger North American trial, which was reported last October at the annual meeting of the American Heart Association. That trial included more than 3,000 volunteers.

“To me, based on the results that I have seen, this is more than just a weight-loss drug,” Van Gaal said. “For me, it is a drug that helps patients who are overweight to reduce cardiovascular risk. We can consider it to be a new approach in reducing cardiovascular risk factors.”

If and when the drug is marketed, its target population will be overweight people with expansive waistlines who have major cardiovascular risk factors, such as diabetes, high blood pressure and high cholesterol, he said.

They would probably take the drug indefinitely, in the same way that people take cholesterol-lowering statin drugs or medications for high blood pressure, Van Gaal said.

“Obesity is a metabolic disorder, and I don’t know of any medication that cures metabolic disorders,” he added. “If you take away the statins, cholesterol goes up. If you take away hypertension medications, blood pressure goes up.”

Other uses of rimonabant are being explored, Van Gaal noted. For example, a trial showed it can help smokers give up the habit, and lose weight as well. Since weight gain is often used an excuse to keep smoking, the combined effect “is very important,” he said.

Rimonabant would be a welcome addition to the weight-reduction treatments now in use, said Dr. G. Michael Steelman, president of the American Society of Bariatric Physicians, who specialize in obesity treatments.

“It is always a good thing to have a new tool,” Steelman said. “The fact that rimonabant acts in a different way than what we have had in the past means that we might be able to help some people we haven’t been able to help with appetite-suppression medication.”

But Steelman said caution is needed in appraising the value of rimonabant. “The flip side is what is statistically significant to the medical mind may not be significant to the patient,” he said. “Losing 16 to 20 pounds in a year may not be that significant to them.”

Rimonabant will be “one tool in the toolbox,” Steelman said. “Diet and exercise will continue to be the major elements.”

Dr. Paul Shekelle, a health scientist at RAND Health, a research institute in Santa Monica, Calif., recently headed a study on weight-reduction medications. He said rimonabant “will be a welcome addition to the physician’s armamentarium” but something short of a miracle cure for obesity.

Older drugs suppress appetite by acting on a different set of receptors, those that interact with chemicals such as caffeine, Shekelle said. The weight loss reported in the people taking the higher dose of rimonabant was in the same range as achieved with the older drugs, and so was the spectrum of side effects that caused people to drop out of the study, he said.

More information

University Hospital Antwerp

The U.S. Centers for Disease Control and Prevention has more on obesity.




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