What's In A Weight Loss Benchmark?

Drugmaker Vivus's stock soared yesterday, on word that the company's experimental weight-loss medication, Qnexa, has passed muster in two Phase III clinical trials. Big money awaits those who can bring a safe and effective obesity medication to market (to the tune of $10 billion, per Bloomberg). The Knight Science Journalism Tracker is following coverage of the results, and briefly puzzled over some of the Food and Drug Administration's benchmarks for new obesity medications.
The research by the drug’s maker, Vivus, found that about two-thirds of subjects lost at least 5 percent of their body weight. Scientifically significant it might be, but how significant is a 15-pound weight loss for somebody who weighs 300 pounds?
Maybe not much cosmetically, but perhaps more than you'd think when it comes to health. The Tracker's very question came up for me last spring, while I was writing a C&EN cover story on the obesity drug landscape. Treating obesity isn't just about fitting into that new pair of skinny jeans- it's about fixing the consequences of excess weight, such as cardiovascular disease and diabetes. Donna Ryan, a physician and associate director for clinical research at Pennington Biomedical Research Center, a hub for obesity research located in Baton Rouge, La., told me that a little bit of weight loss can go a long way to helping an obese patient improve risk factors for those diseases. For instance, in the Look AHEAD (Action for Health in Diabetes) study at the National Institute of Diabetes and Digestive and Kidney Diseases, researchers have found that a 9% weight loss doubled diabetics' chances of achieving the American Diabetes Association's goals for blood sugar and lipid levels. And a diabetes prevention program found that a modest weight loss of 6-7% lowered an at-risk nondiabetic person's risk of developing Type 2 diabetes by 58%. "You don't have to do what people do on "The Biggest Loser"- weight loss between 5 and 10% can give enormous benefits," Ryan, who has advised Vivus and several other companies developing obesity medications, said. That's part of the reason why FDA's benchmarks are set where they are. Ryan noted that modest weight loss does the most for controlling blood sugar levels. To have an effect on cholesterol levels, a bit more weight loss seems to be necessary, in the neighborhood of 20%. In the Phase III trials, patients on Qnexa saw improvements in risk factors such as blood pressure, lipid levels, and blood sugar.

Author: Carmen Drahl

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  1. Drinking one less soda per day could have similar results, or having a few less meat-centered meals each week. Why is it that there is even a market for weight-loss drugs? People who are willing to take a pill every day but not change their habits… I mean, yes, I would love to lose my weight faster and easier, but how will I know I won’t gain it right back once I’m done my prescription? Yoyoing can be horribly unhealthy, too.

  2. One of the interesting things about how some of the weight loss clinical trials are designed is that subjects must also have a reduced calorie diet and/or exercise regimen. So the placebo group also experiences a measurable amount of weight loss.

  3. It doesn’t seem wrong to anyone else that they are measuring how well a weight-loss drug works by restricting people’s diets and making them work-out more?


  1. Treating the Obesity Epidemic - [...] Vivus saw its experimental weight-loss medication, Qnexa, pass two Phase III clinical trials C&EN reported on September 10, and…