(9-March-2005/Reuters) Sanofi-Aventis SA's expe- rimental obesity drug helped patients shed three times as much weight as those on a placebo, but patients gained some of that weight back in the second year, according to a study released on Tuesday.
 

The drug, called Acomplia, takes a novel approach by tinkering with the same biological switch in the brain that makes people hungry when they smoke marijuana, possibly by blocking cravings.


About 32 percent of the overweight and obese patients taking the drug in the trial lost a tenth of their body weight after two years. Eleven percent of patients on placebo were able to lose 10 percent of their body weight after two years.


After one year, about 40 percent of patients on the drug, also known by the chemical name rimonabant, had lost a tenth of their weight, according to data from the 1,507-patient study presented at the American College of Cardiology meeting.


"There is a slight weight regain if you analyze the data after two years," said Luc Van Gaal, professor at the University Hospital Antwerp and a lead investigator in the company-sponsored study.


But "that is something we saw in the placebo group and have seen in other trials," he said.


At two years, patients on the drug lost an average 7.2 kilograms, or 15.8 pounds, compared with a loss of 2.5 kg, or 5.5 lbs, on placebo. At the one year mark, Acomplia patients had shed 8.6 kg, or 18.9 lbs, compared with a loss of 3.9 kg, or 8.6 lbs on placebo. So the difference between the placebo and Acomplia groups remained about the same.


Investors, however, were disappointed by the latest trial results, as Sanofi shares fell 2.3 percent in Paris to close at 62.80 euros on Tuesday.


"Some people might be a little disappointed that some of the numbers were not bigger in terms of the percentage of patients losing a significant proportion of their weight," said Mike Ward, an analyst at Code Securities in London.


Investors have high hopes for the drug, which is being tested to tackle two of the biggest risks for heart disease: obesity and smoking. The world's third-biggest drugmaker after a merger sparked in part by Acomplia expects to file for U.S. marketing approval in the second quarter of 2005.


Doctors are eager for a safe and effective treatment for obesity, which many believe has reached epidemic proportions.


Some expect Acomplia will post annual sales of at least $3 billion and help drive Sanofi's growth as it contends with patent challenges and competition for its current drugs.


Acomplia patients had an average 2.9-inch reduction in waist circumference, compared with 1.3 inches in the placebo group. Excess abdominal fat elevates heart-disease risk.


Those on the drug also got a boost in levels of HDL, the so-called good cholesterol, which researchers believe may help reduce heart risk. HDL levels increased nearly 30 percent in Acomplia patients vs. 17 percent in the placebo group.


Some Acomplia patients also experienced a drop in triglycerides, or fats in the blood -- nearly 9 percent saw a drop compared with 6.3 percent on placebo.


Unpleasant side effects such as vomiting and nausea forced about 19 percent of patients to drop out of the trial, compared with a dropout rate of 13 percent on a placebo.


The dropout rate, which concerned some experts, is similar to previous two-year data. About 15 percent of patients withdrew after one year. (Additional reporting by Ben Hirschler in London and Bill Berkrot in New York)