The US Food and Drug Administration (FDA) yesterday approved the weight-loss drug Qsymia, made by drug company Vivus, of Mountain View, California. It is the second approval of an obesity medication in the past month.
Obesity drugs have had a long and chequered history, with trial after trial showing moderate — if any — benefits, and a host of side-effects, particularly heart problems. In July 2010, the FDA had declined to approve Qsymia (when it was reviewed under its previous name Qnexa) on the basis that those risks outweighed the benefits of the treatment.
The FDA’s turnaround this week came after Arena performed echocardiograms in nearly 8,000 people to measure heart-valve function, which revealed that there was no increase in heart-valve abnormalities among those taking the drug. The firm has agreed to run six post-marketing studies, including a long-term cardiovascular trial, and patients with congestive heart failure are advised not to take the drug.
“I felt the benefits outweighed the risk,” says Ida Johnson Spruill, the consumer representative on the FDA advisory committee and a diabetes specialist at the Medical University of South Carolina in Charleston.
The FDA has clearly made a similar calculation in approving Qsymia. In a statement, the agency said that its use will be restricted to adults with a body mass index (BMI) of 30 or greater (classed as obese) or adults with a BMI of 27 or greater (overweight) who have at least one weight-related condition, such as high blood pressure (hypertension), type 2 diabetes, or high cholesterol (dyslipidemia). “Qsymia must not be used during pregnancy because it can cause harm to a fetus,” it added.
In randomized, placebo-controlled trials of about 3,700 obese and overweight patients, one year of treatment with Qsymia gave an average of 6.7–8.9% weight loss, depending on dosage. Two-thirds of patients taking the drug lost at least 5% of their body weight, compared to just one in five patients taking a placebo.
However, the FDA emphasized that:
Vivus Inc. will be required to conduct 10 postmarketing requirements, including a long-term cardiovascular outcomes trial to assess the effect of Qsymia on the risk for major adverse cardiac events such as heart attack and stroke.
As we wrote earlier this month in ‘Law spurs regulators to heed patients’ priorities’, the FDA’s risk–benefit calculations on drugs such as Qsymia and Belviq are expected to be made more explicit under a new system that should be rolled out by October 2013.