February 23rd, 2012
FDA Advisory Panel Gives Green Light to Qnexa Diet Pill
Larry Husten, PHD
Breaking a long streak of bad news for diet drugs, an FDA advisory panel on Wednesday voted 20-2 in favor of approval for Qnexa, the combination of phentermine and topiramate under development by Vivus. Panel members strongly suggested that Vivus be required to perform a cardiovascular outcomes trial, though it was not immediately clear if this would have to be completed prior to approval.
Birth defects associated with Qnexa were another source of concern. The panel expressed strong support for a risk evaluation and mitigation strategy (REMS) to accompany any approval. But the panel ultimately was impressed by data showing a 10% weight loss at 2 years for people taking the drug.
Of all the obesity drugs, this one “has the highest efficacy in terms of weight loss,” panel member Sanjay Kaul told Bloomberg News. “That shifts the balance in terms of requiring a post-approval study rather than a pre- approval study,” .
Kaul told CardioExchange that the 20-2 vote appears more enthusiastic than the actual sentiment of the panel. Panel members remain concerned about the uncertainty regarding cardiovascular risk, including the possible adverse effects on blood pressure and heart rate. Kaul said the panel was impressed by the company’s proposed REMS, but there is little evidence demonstrating that even a strong REMS can significantly reduce adverse outcomes like birth defects.
Two other diet drugs, Contrave, the combination of naltrexone and bupropion, from Orexigen, and locaserin, from Arena, have been struggling to gain FDA approval in recent years. No new diet drug has been approved for marketing in the U.S. since 1999.
4 Responses to “FDA Advisory Panel Gives Green Light to Qnexa Diet Pill”
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another sop to drug companies and a disaster in the making.
I have a feeling that a lot of a physicians will have trouble swallowing this FDA approval. It will be interesting to see if the Medical Letter on Drugs and Therapeutics reviews this combo.
I was astonished by the Adcom vote and the FDA presentation. Regarding CV risks, given the history of other drugs–eg Meridia–and the well known issues with phenteramine, it amazed me that they let perceived efficacy trump known CV risk. Regarding the birth defects, well I simply don’t get it. I believe the quoted risk is 300-500% increased chance of birth defects/cleft palates, and that may be an underestimation since it appeared to be derived by comparing the risk to people taking other anti-seizure meds rather than NO meds. A REMS will be a disaster, particularly as obese women often don’t even realize they are pregnant until late in the first trimester. And then what? What if the obese pregnant woman is also “pro-life”….Finally, the efficacy stats were murky since that 10% weight loss was really seen only in the high dose pts which carried the most risks but the company and the FDA seemed to gloss over that and pretend the lower doses would work as well. We desperately need meds to help with the obesity epidemic, but this has far too high a risk profile. And it were so good, since both drugs are readily available, why aren’t docs all over the country prescribing them.
I would advice te patients seeking this medication to invest in Weight Watchers or in a good weight loss program as adviced by their physician.