At obesity treatment centers, nearly every patient now asks for Acomplia (rimonabant), the New York Times reports. But many medical researchers, the newspaper found, say that while rimonabant may be intriguing, "the mythology in the making is hardly justified by what is known so far.

The Times reports:

There are no published studies from clinical trials to justify any of the claims for what some patients are already calling a miracle drug. The data that the company has presented indicate that rimonabant is about as effective for weight loss in obese people as two other drugs already on the market. Nor are there any clinical tests to indicate how or whether it would work in people who are only moderately overweight, hoping to lose a few pounds after the holidays.

Rimonabant has not been approved for sale in the United States or anywhere else. Sanofi-Aventis has not yet submitted its application for marketing to the Food and Drug Administration. The company says it plans to apply early next year. If the agency decides it is a high-priority application, it must issue its decision within six months; if not, it has 10 months to decide.

All that adds up to a problem, says Dr. Madelyn Fernstrom, who directs the weight-management center at the University of Pittsburgh Medical Center.

"It's disturbing, in my view, the amount of attention this compound is getting," Fernstrom said. "I'm underwhelmed by the results so far."

Dr. Jeffrey Flier, an obesity researcher at Harvard Medical School who consults for several biotechnology companies, says he regularly gets calls from venture capitalists and other drug companies asking what he knows.

"The question is, 'Is this stuff any good?' " Flier said. "Or, 'I hear it's not quite as good as somebody thinks it is.' " He said he tells them that "from what I hear, it's not good enough to have this sort of hype around it."

Fernstrom says the enthusiasm of patients for rimonabant reflects the desperation that obese people often feel. Most have failed with diet after diet. The two drugs on the market for obesity, sibutramine (sold under the brand name Meridia), which diminishes appetite by affecting brain neurotransmitters, and xenical (sold as Orlistat), which blocks the absorption of fat from the intestines, result in modest weight loss.

Rimonabant has a story that seems to make sense.

Rimonabant blocks a protein in brain cells that allows cannabis, the active ingredient in marijuana, to work. It also blocks the body's own versions of cannabis, the so-called endocannabinoids. Marijuana is supposed to increase appetite. So a drug that blocks cannabis, it seems logical, should suppress appetite.

Obese people have more receptors for endocannabinoids than thin people, said Dr. F. Xavier Pi-Sunyer, a professor of medicine at Columbia University and the principal investigator of a large rimonabant study in the United States and Canada. The drug does not completely block these receptors, Pi-Sunyer said.

The idea of blocking these receptors worked in animals.

Rmonabant, said Dr. Jeffrey Friedman, an obesity researcher at Rockefeller University, "is the first in what I think will be a wave of rational therapies" that attack what has recently been learned about how eating is controlled. But with rimonabant, he said, "the issue is, what's the safety and efficacy?"

Sanofi-Aventis says it has enrolled more than 13,000 subjects.

Eighty percent were women, weighing an average of 220 pounds. A year later, as a group, they had lost an average of about 14 pounds.

Half dropped out along the way. Some cited problems like nausea. Another reason, said Dr. Douglas Green, the company's vice president for regulatory affairs, is that the study subjects had expected to be thin and they were not.

"They are looking to go from being obese to someone who can suddenly show up in a swimsuit at a beach," Green said. "That's their expectation."

In presenting its findings, Sanofi-Aventis discarded thousands of participants who dropped out. Some say that is reasonable because it shows what can happen if people stay with a treatment. But statisticians often criticize it, saying it can make results look better than they are.

With an analysis limited to those who completed the study, rimonabant resulted in an average weight loss of about 19 pounds, Pi-Sunyer said.