The findings, which appear in the Feb. 15 issue of the Journal of the American Medical Association, could help Acomplia compete against weight-loss drugs already on the market, such as Abbott's Meridia (sibutramine) and Roche's Xenical (orlistat).

Sanofi filed a new drug application for Acomplia with the Food and Drug Administration last year. The FDA is expected to wrap up its review of the weight-loss product in the next week or so.

First in Class of Cannabinoid-1 Receptor Blockers

"The study showed that Acomplia is effective -- and as effective, if not a little more, than the two other drugs already approved for weight loss: sibutramine and orlistat," the study's lead author F. Xavier Pi-Sunyer, of St. Luke's-Roosevelt Hospital Center, told United Press International.

"It's an advance," Pi-Sunyer said, adding that he had no other ties, financial or otherwise, to the company.

"It's unusual in that it's a two-year trial and it shows continued effect over two years," he said. "In addition, the drug works by a different mechanism of action, so it has the potential to be important."

If Acomplia is approved by the FDA, it would be the first in class of drugs known as selective cannabinoid-1 receptor blockers.

Sanofi-Aventis said in a statement that the results are consistent with three other phase 3 trials involving Acomplia.

In these studies, [Acomplia] has demonstrated a wide array of cardiometabolic improvements in blood sugar levels (HbA1C), blood lipid levels (HDL-cholesterol and triglycerides), blood pressure, weight and waist circumference, as well as improvements in such emerging cardiometabolic risk factors as adiponectin and C-reactive protein (CRP), which are markers of inflammation associated with cardiovascular risk, the company said.

The improvements seen in HbA1c, HDL-cholesterol, triglycerides, adiponectin and CRP were beyond what could be explained by weight loss alone, suggesting a possible direct effect of [Acomplia] on cardiometabolic risk factors, Sanofi added.

Prudential analyst Tim Anderson noted in a recent research report on Sanofi-Aventis that company officials have been consistent in predicting the drug would be launched by the end of the second quarter of this year.

But Anderson put the odds of Acomplia getting full approval by the FDA's February deadline at less than 50 percent, saying an approvable letter requiring the resolve of some minor issues prior to launch is more likely.

"We continue to expect that the Acomplia label will probably be restricted to some form of obesity claim (plus or minus smoking cessation) and that approval will likely be contingent on the implementation of some form of risk management program," Anderson wrote.

Didn't Involve Behavioral Counseling

Some researchers, however, think more data are needed before clearing the drug for widespread use.

It's interesting preliminary data that is not sufficiently compelling for the drug to be included in clinical practice yet, Denise Simons-Morton, of the National Heart, Lung, and Blood Institute, who co-authored an editorial in the journal, told UPI.

Simons-Morton said the methodology of the study does not allow for conclusively determining what impact the drug has on weight, its long-term effects or its safety.

"Forty-seven percent of people [stopped] taking the treatment and they didn't really give that much information about those people," Simons-Morton said. "Lifestyle modifications, such as diet and exercise, are often criticized because they're difficult for patients to adhere to, she added, but this study suggests people can't adhere to taking drugs either, even if it's a placebo."

For those who completed the study, Acomplia was well-tolerated with nausea being the most common adverse event.

The safety seems good for two years, Pi-Sunyer told UPI. Although slightly more patients in the Acomplia group dropped out during the first year (12 percent vs. 7 percent of the placebo group), there was no differential dropout for adverse effects in the second year, he said.

Simons-Morton also pointed out that the study didn't involve intensive behavioral counseling of patients to make lifestyle modifications.

"We know from other studies that you need to do behavioral counseling to be effective," she said, noting that Meridia and Xenical have not been shown to be more effective than lifestyle approaches.

"I honestly don't understand why people think the drugs are so promising when you put it in that context," she said.

In the study, more than 3,000 obese adults were randomized to receive either placebo or Acomplia. At the end of one year, patients receiving the highest dose of Acomplia (20 mg) had a greater mean reduction in weight (6 kg or about 13 pounds) than the placebo group. The Acomplia group also had greater reductions in waist circumference and triglyceride levels, while at the same time experiencing a greater increase in HDL, or good cholesterol, levels.

Patients who stayed on Acomplia during the second year of the study maintained the weight loss and other favorable changes while those who were switched to placebo regained weight.