Weight-loss drug Qnexa is denied approval

The Food and Drug Administration on Thursday declined to approve the prescription weight-loss drug Qnexa. But there may still be hope that the medication reaches the marketplace eventually, said officials for Vivus Inc., which developed the drug.

Qnexa is a combination of two existing drugs, phentermine and topiramate. In July, an advisory committee to the FDA voted against approval of the product, so Thursday’s denial was not a surprise. However, in an investors’ conference call Friday, officials for Vivus said they are “encouraged” they can satisfy the agency’s concerns.

The FDA has asked the company to provide additional data about whether the medication can cause birth defects and to quantify what the risk of birth defects might be. The agency has also requested data on whether the slight increase in heart rate that is linked to the drug increases the risk of cardiovascular events, such as heart attack and stroke.

“We have a plan to answer the FDA’s questions,” said Leland Wilson, chief executive of Vivus, which is based in Mountain View, Calif. “We believe sufficient data exist to address the questions and no additional studies are required.”

Vivus last month released data from a two-year study of 4,323 patients showing there was no increased risk of cardiovascular events in people taking the medication compared with people taking a placebo. Data show people on the drug have an average weight loss of at least 10% of total body weight and showed improvements in blood pressure, according to Vivus.


Although the picture for an eventual approval of Qnexa may be somewhat brighter, this has not been a good year for progress on new drugs to help overweight and obese Americans. Last week, the FDA informed Arena Pharmaceuticals that it would not approve its product, lorcaserin, due to concerns about its marginal effectiveness and about cancers that occurred at higher-than-usual rates during clinical trials.

On Oct. 8, Abbott Laboratories said it would withdraw its diet drug Meridia from the market at the request of the FDA and following an FDA advisory panel’s concerns about its safety. A study found that Meridia increases the risk of heart attacks and strokes in people with cardiovascular disease.

“In the end the right decision will be made,” Wilson said of Qnexa. The FDA wants to be assured that the medication is used in the right patients. But, he added, “Everyone at the FDA now is clearly up-to-date and knows that obesity is the primary cause of Type 2 diabetes, hypertension, dyslipidemia, etc.”

Related: FDA shoots down another weight-loss drug

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