FDA approves new diet drug: Phentermine-topiramate combo

July 17, 2012

Mountain View, CA - The FDA has approved the weight-loss drug Qsymia (formerly named Qnexa; Vivus, Mountain View, CA), which now joins lorcaserin (Belviq, Arena Pharmaceuticals, San Diego, CA) as the first antiobesity medications to enter the US market since 1999. News of the agency's decision was announced late Tuesday[1].

Qsymia, a controlled-release preparation of phentermine and topiramate in one capsule, is now indicated for use in adults with a body-mass index (BMI) >30 kg/m2 or adults with a BMI of >27 kg/m2 and at least one weight-related condition such as hypertension, type 2 diabetes, or dyslipidemia.

The approval is accompanied by a risk evaluation and mitigation strategy (REMS), including a medication guide advising patients about important safety information and specific requirements for prescriber training and pharmacy certification. The drug "will only be dispensed through specially certified pharmacies," according to the FDA statement. Of special note, the drug must not be used during pregnancy; details about the risk of the drug combo in pregnant women are included.

The agency's statement also notes that the drug can increase heart rate, which warrants regular monitoring, and should be used with caution in people with recent unstable heart disease or stroke. The sponsor will be required to conduct a long-term, postmarketing cardiovascular outcomes trial to assess the effect of Qsymia on the risk of major adverse cardiac events.

In February, an FDA advisory panel voted overwhelmingly in favor of the drug's approval for obesity, despite some concerns about possible adverse effects, as reported by heartwire .

The agency then took the step—not unusual in such cases—of giving the company a three-month extension on the period during which it could review its application, which ended today. That allowed the FDA to consider the REMS for Qsymia that Vivus had submitted on April 4[2].

Many on the advisory panel had stated that their vote favoring Qsymia—it was ultimately 20 to 2—assumed that the company would in fact submit and implement a REMS, parts of which Vivus described at the hearing. That regulators granted an extension to facilitate that process was as good a sign as any that it was leaning toward a positive decision.

Both the FDA and its advisory committee had decided against approval of Qsymia during its first round of consideration in October 2010, pending a more comprehensive safety assessment. Lorcaserin had followed a similar path in the premarket process, having been denied approval the same week for similar reasons; the agency approved lorcaserin just a few weeks ago.

Many people eagerly watching the web for breaking news on the FDA's decision were confused by a mid-day story by USA Today announcing approval: apparently a "best-guess" story, prewritten, that accidentally went live online before the final word came down.

That story proved prescient, but was not confirmed until much later in the day.


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