Qnexa Diet Pill Approval Delayed in Face of New Safety Plan

Federal drug regulators have decided to delay a decision on whether to approve the weight loss drug Qnexa, which includes the active ingredient of Topamax and one of the active ingredients from the recalled diet pill Fen Phen. 

The FDA was scheduled to make a final decision on the approval of the new Vivus, Inc. diet pill this month, but now the agency indicates that a decision has been delayed and will be made on or before July 17.

Qnexa is a proposed weight loss pill, which contains a combination of phentermine, an amphetamine, and topiramate, an antiseizure drug that is the active ingredient in Topamax. Phentermine was the “Phen” in Fen Phen, which was recalled due to heart problems, and concerns emerged last year about side effects of Topamax increasing the risk of cleft palate and cleft lip when used during pregnancy.

The FDA has rejected Qnexa once before, but an advisory panel voted 20-2 in February to recommend that the agency now approve the drug, indicating that its weight loss effects could reap huge health benefits that justify the potential risks. If approved, it would be the first new FDA-approved weight loss drug on the market in over a decade.

The latest delay, according to officials at Vivus, is due to the review of a new drug safety plan presented by the company, which the FDA must review. A three month delay is standard when a risk management plan has been submitted.

While there were no details on the plan, it comes on the heels of another FDA advisory committee meeting that called for the FDA to require that new weight loss medications prove they do not increase the risk of heart attack before approval.

Weight loss drugs have been plagued by serious side effects, and the last new prescription medication to help dieters was Roche’s Xenical, which was introduced in 1999

Xenical (orlistat 120mg) is a prescription medication that was approved by the FDA in 1999. The lower dose Alli (orlistat 60mg) is an over-the-counter weight-loss drug that was approved in 2007. Both drugs are marketed by GlaxoSmithKline, PLC, though Xenical is manufactured by Roche.

The FDA issued a liver injury warning for Xenical and Alli in May 2010.  Last April, Public Citizen, a consumer watchdog group, petitioned the FDA to recall Alli and Xenical from the market.