F.D.A. Rejects Qnexa, a Third Weight-Loss Drug

The Food and Drug Administration rejected another new diet pill on Thursday, the latest setback in the quest to develop treatments for overweight Americans amid the nation’s obesity epidemic.

The rejected drug, called Qnexa, is the third weight loss medicine to run into trouble this month because of concerns about safety. Last week, the F.D.A. declined to approve another new drug, lorcaserin, because it caused tumors in rats. And earlier in the month it forced the withdrawal of Meridia from the market after 13 years, citing the risk of heart attacks and strokes for certain patients.

“It looks pretty bleak out there for anyone trying to get a drug approval for weight loss,” said Dr. Ken Fujioka, director of the center for weight management at the Scripps Clinic in San Diego.

Vivus, the developer of Qnexa, said late Thursday in a statement on its Web site that the F.D.A. had requested that the company provide a thorough evaluation of the drug’s potential for causing birth defects and heart problems.

The company, based in Mountain View, Calif., said it was confident it could provide this information to the F.D.A. in about six weeks. If the F.D.A. were to be satisfied, the drug could win approval sometime next year.

There has been no new prescription diet pill approved since Roche’s Xenical in 1999. Xenical is now the only drug approved for long-term use in managing weight.

“It’s tough to be a doctor and try to do something about the biggest problem in the U.S.,” said Dr. Fujioka, who is a consultant to some drug companies, including Vivus.

Some drug companies shied away from the diet market, after part of the popular fen-phen diet combination was removed from the market in 1997 because it damaged heart valves. The debacle resulted in huge legal settlements.

The F.D.A.’s decision on Qnexa was not unexpected, given that an advisory committee to the agency had voted 10 to 6 against approval in July. […]

The F.D.A. does not comment or publicly release its reasons for turning down a drug.

Dr. John Jenkins, director of the agency’s office of new drugs, told reporters this month that the agency was “committed to working toward approval” of new obesity drugs, “so long as they are safe and effective for the population for which they are intended.”

Diana Zuckerman, president of the National Research Center for Women and Families, said the diet drugs that have made it to market are not very effective, so the F.D.A. should pay close attention to safety. “The vast majority of people taking them don’t stay on them long enough to get any health benefit,” she said. […]

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