Qnexa, an investigational drug to promote weight loss, has divided public health advocates, based on comments made Wednesday at a Food and Drug Administration advisory committee hearing.
The advisory committee will vote later Wednesday in Silver Spring, Md., on whether to recommend approval of Qnexa, made by Vivus of Mountain View, Calif. The FDA will rule on the new drug application later this year, but it usually follows the advice of advisory committees.
If approved, Qnexa would be the first prescription diet drug to reach the market since 1999. The drug is a combination of the anticonvulsant topiramate and the diet drug phentermine. Studies show the medications produced an average of about 10% loss of body weight in 56 weeks of use. But the drug is linked to a small risk of birth defects and an increase in heart rate.
In a public comment period, those opposed to the drug's approval said they feared the potential for birth defects because many of the people interested in taking the drug will likely be women of childbearing age.
Dr. Sidney Wolfe, director of the Health Research Group at Public Citizen, also expressed concern about the potential for cardiovascular side effects. "Diet drug history is littered with those banned only after they found about cardiovascular risk areas," Wolfe told the committee.
But advocates for approval of Qnexa criticized the makeup of advisory committee, noting that none of the 22 members was a physician actively involved in treating obesity. Some also complained that the FDA places a higher safety burden on obesity medications.
"Too often, and for too long, treatment avenues to address obesity have come under a different microscope than the treatments for other disease states," said Chris Gallagher, a spokesman for the American Society for Metabolic and Bariatric Surgery.
This is the second time the drug has come before the Endocrinologic and Metabolic Drug Advisory Committee. The panel voted 10 to six against approval of the medication in 2010 and the FDA subsequently denied the application. Since then, Vivus officials have been in discussions with the agency on how to best resolve concerns over the drug's side effects.
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