Safety Concerns Prompted FDA’s Rejection of Qnexa and Lorcaserin
The wait for the release of a new weight-loss drug got longer recently as regulatory decisions were not in favor of fat-fighting treatments. The US Food and Drug Administration decided in October not to approve two anti-obesity treatments, sending complete response letters (CRLs) to the drugs’ sponsors.
In both cases, FDA followed the advice of the Endocrinologic and Metabolic Drugs Advisory Committee, which recommended that the two drugs, Qnexa (phentermine/topiramate) by Vivus (Mountain View, CA) and lorcaserin hydrochloride by Arena Pharmaceuticals (San Diego), not be approved because of health risks. In the CRL for Qnexa, FDA requested more study results and information about the drug’s risks such as cardiovascular events and birth defects, according to Vivus. Arena announced that FDA’s main concerns with lorcaserin were that early testing showed mammary tumors in rats, and that the weight-loss experienced by people without Type 2 diabetes in clinical trials was marginal. FDA asked for more data and said more clinical testing may be required if concerns about the tumors are not alleviated.
Another setback for obesity treatments was the voluntary recall of Meridia (sibutramine) in the US and Canada by Abbott (Abbott Park, IL) in October. FDA requested the recall due to risks of stroke and cardiovascular side effects. Meridia was banned in Europe in January.
There is hope, however, for approval of a third new treatment. Contrave (naltrexone sustained release [SR]/bupropion SR), by Orexigen Therapeutics (San Diego), will face the advisory committee early next month, on Dec. 7. FDA will decide by Jan. 31, 2011 whether to approve the drug.
See related articles:
FDA Panel Votes ‘No’ on Arena’s Obesity Drug
I read an interesting sites information and a question posted there about Qnexa’s chances of approval… eventually. It looks like Qnexa could still be approved, and for that matter I suppose Lorcaserin too. But I would rather play the VVUS stock (Vivus, Qnexa’s maker) thinking that is effectiveness may have something to play into a future FDA decision. What I like about Contrave’s chances are the 2 drugs mixed do not seem to have the side effects that the ones in Qnexa’s mix do… but really its anyone guess as to what happens.
Naltrexone’s side effects seem relatively mild/moderate:
Nausea, headache, dizziness, anxiety, tiredness, and trouble sleeping may occur…
Bupropion side effects: Weight loss, nausea, and headaches
Both drugs are relatively tolerated well. This being said, it looks like contrave could be approved. HOWEVER… Qnexa is just combining two drugs already approved by the FDA and it was not.
I think the real situation here is that the FDA knows that people will not just take a weight loss medication for 3 months and then live happily ever after, rather it could be used for years.
Does Contraves combination of the main side effects listed above seem to be acceptable for long term use? We will see in December when the FDA panel gives its two cents.
Thanks for your comment. It will be interesting to see how it plays out. I think FDA has a really tough decision to make—on the one hand there is the obesity epidemic that seems to be steadily growing, and on the other hand the safety of any weight-loss drug is of extreme importance because of the large number of people who will likely take it and the length of time they will probably be on it. CDC estimates that two-thirds of Americans are overweight or obese. Given the worrisome nature of those stats, I’m glad to see that FDA is not rushing to approve a drug that may be later recalled due to health risks. –Alexis