WEDNESDAY, June 13, 2007 (HealthDay News) -- The weight-loss drug rimonabant should not be approved by the U.S. Food and Drug Administration because of continuing concerns about increased risks for suicidal thoughts among some users, an advisory panel concluded Wednesday.
The unanimous 14-0 vote followed another unanimous vote by the panel that drugmaker Sanofi-Aventis had failed to prove the safety of its drug, the Associated Press reported.
"There is a reasonable suspicion we better learn some more and watch this affair more closely before we launch into massive use of this drug," said panelist Dr. Jules Hirsch, of The Rockfeller University.
While the FDA isn't bound to follow the recommendations of its advisory panels, it typically does.
Rimonabant has been touted by Sanofi-Aventis as a wonder drug that aids in weight loss and also helps people stop smoking, but the drug has been linked to increased risk of suicidal thoughts among some people who take it.
This side effect has delayed FDA approval, and is, as Dr. Eric Colman, deputy director of the FDA's metabolic and endocrine drugs office, told the panelists Wednesday, "obviously, a big concern for us," the AP reported.
The manufacturer, in its own testimony before the panel, agreed.
"Who is the right patient to receive rimonabant? Not everybody," Richard Gural, of Sanofi-Aventis, testified. The drug is not right for anyone with a history of depression or suicidal thoughts, or who has been diagnosed with depression or is currently taking antidepressant medication, he added, according to the AP.
Gural suggested that patients be screened for depression before they were prescribed the drug. He also recommended that patients visit their doctors five times during the first year of treatment to be reassessed, the AP said.
Despite the significant side effect, some experts said they believe the drug should be approved.
"Well-conducted, large clinical trials provide clear and compelling evidence that rimonabant facilitates weight loss," said Dr. David Katz, director of the Prevention Research Center at Yale University School of Medicine. "Those same trials suggest the drug is safe and generally well-tolerated. In my opinion, there is ample evidence to support FDA approval of rimonabant at this time."
"There have been a significant number of studies that have looked at the benefits versus the risks of rimonabant," said Cathy Nonas, director of the obesity and diabetes program at North General Hospital, in New York City. "With any medication, there are always possible side effects, but that doesn't mean that it's not going to be beneficial for many people."
But, the consumer advocacy group Public Citizen said it remains opposed to the drug's approval.
In testimony prepared for the advisory committee, Dr. Sidney Wolfe, director of the organization's health research group, said, "The evidence for increased suicidal tendencies and depression is of particular concern for a drug targeted toward the obese, a population that has been shown to have a significantly higher incidence of depression and eating disorders compared to non-obese individuals."
Wolfe also pointed to what he called the paucity of information on the effect of using the drug over the long term.
"Because rimonabant is the first drug of its class, there is no data on its use in humans over an extended period of time," he testified. Because people on rimonabant tended to regain weight after discontinuing use, many consumers may take the medication for many years, Wolfe said.
But Nonas said that as with the use of any drug, patients need to be monitored for possible side effects.
"You do what we do with any new medication, you give it to your patient, and you bring them back for monitoring to make sure that it is working the way it should be working," Nonas said.
While patients need to be watched for depression, Nonas said, she doesn't think a "black box" warning is necessary. "A black box warning would be needed if people were committing suicide, but that's not the case," she said.
The FDA is expected to decide by July 27 whether the drug should be on the market. If approved, the drug would be sold in the United States under the name Zimulti. In Europe, it is sold under the brand name Acomplia.
Last year, the FDA decided not to approve rimonabant as an aid to stop smoking.
When used with a modest-calorie diet and exercise, rimonabant significantly decreases weight and waist size in overweight or obese people, research shows. In studies, patients taking the drug lost about 14 pounds while those on a placebo lost only about 4 pounds. However, patients put the weight back on when they stopped taking the drug, according to Sanofi-Aventis.
In addition, the drug has lead in some instances to psychiatric symptoms, including anxiety, phobias, depression and post-traumatic stress disorders.
Studies found that 26 percent of people taking the drug reported these symptoms, compared with 14 percent of those taking a placebo. Among those taking the drug, 9 percent reported symptoms of depression, compared with 5 percent taking a placebo.
This is a small increase in depression, Nonas said. "It means that 91 percent of the people will not have depression," she said.
People taking rimonabant had a two-fold increase in suicidal thoughts, compared to those taking a placebo. Sanofi-Aventis believes all those cases were due to preexisting depression or other disorders and not directly the result of taking the drug.
Rimonabant works by blocking the same pleasure centers in the body that are triggered when marijuana users get hungry. Blocking the receptors reduces hunger, and people eat less and lose weight.
For more information on obesity, visit the U.S. National Institute of Diabetes and Digestive and Kidney Diseases.