In a rebuke of the Abbott Laboratories diet drug Meridia, eight of 16 members of a Food and Drug Administration advisory panel said Wednesday that the drug should be withdrawn from the U.S. market.
Six of the panelists said the drug should be prescribed only by "specially trained physicians." The other two panelists said a new black box warning should be added to alert doctors to the increased risks of heart attacks and the need for closer monitoring of patients' blood pressure, pulse and body weight.
None of the panelists on the Endocrinologic and Metabolic Drugs Advisory Committee said the drug should remain on the market in its current form, with labeling that says the drug is not intended for patients with a history of heart disease and other cardiovascular issues. So even if the FDA decides to keep it on the market, doctors will be encouraged to prescribe it in limited circumstances.
The FDA usually follows the advice of its panels but is not required to do so. It's unclear what action the FDA will take with half the advisory panel voting for withdrawal.
"Certainly there was not a lot of enthusiastic support for this drug expressed by the committee members," said Dr. Gregory D. Curfman, executive editor of the New England Journal of Medicine and lead author of an editorial published this month questioning the value of Meridia, also known as sibutramine, in light of the cardiovascular risks. "With eight of 16 recommending withdrawal, it will be difficult to ignore that."
A study published this month in that journal found the risk of a stroke, heart attack, cardiac arrest or cardiac death was 16% higher among people taking Meridia, compared with those taking a placebo. All of the 9,804 overweight or obese study participants had a history of cardiovascular disease.
Curfman questioned the proposal to allow for the drug to be prescribed by a specially trained physician because it is vague and adds to the already rising cost of providing medical care.
"We kind of question this approach as being expensive," Curfman said. "And what do you mean by 'specially trained physicians'?"
The Centers for Disease Control and Prevention estimate that two in three Americans are overweight and one in three is obese. Though the drug market is hungry for an effective diet pill, the idea has been difficult to pull off.
There has not been a prescription pill for weight loss approved since 1999, when Xenical, which works by blocking the absorption of fat, was approved. And although the FDA allowed a version of Xenical known as Alli to be sold over the counter, doctors say gastrointestinal side effects such as diarrhea have kept many consumers from taking it for long periods.
Meridia has not been a big seller. Revenue from the pill has decreased amid criticism of its heart risks. Meridia's maker, North Chicago-based Abbott, says it no longer promotes the drug in the U.S., where its sales are projected this year to be $30 million.
But Abbott and some doctors say Meridia has a niche.
"We continue to believe that there are appropriate and identifiable patients that derive benefit from sibutramine," said Dr. Eugene Sun, vice president of global pharmaceutical development at Abbott.
Prescription diet pills have had trouble winning over consumers and doctors because of safety issues and side effects. In 1997, a diet drug combination known as fen-phen was yanked from pharmacy shelves after it was linked to heart-valve damage.
On Thursday, the same FDA panel will weigh in on another diet drug. The drug lorcaserin works in a manner similar to fen-phen, stimulating a receptor in the brain to help block signals linked to appetite so the person taking the drug eats less. But studies have shown lorcaserin is more selective in the receptors it targets than the fen-phen combination, so its side effect profile is better.
An FDA staff report issued Tuesday on lorcaserin in preparation for Thursday's panel said the drug satisfied the agency's "categorical efficacy criterion," or effectiveness, "by a slim margin" and raised safety issues such as memory problems and a link to heart-valve damage.