Vivus’ Qnexa may help in weight loss, but it also now risks losing its place in the market following FDA’s Advisory Committee’s ruling July 15. The panel of medical experts did not question the effectiveness of the drug, but rather voiced its concerns over safety of the medication.
The FDA’s Endocrinologic and Metabolic Drugs Advisory Committee voted 10–6 against recommending approval for the drug, a combination of phentermine and topiramate. Phentermine is the ‘phen’ in infamous weight-loss drug Fen-phen, which was pulled form the market in the late ’90s due to its damaging effects on the heart. Likewise, topiramate was studied several years ago and was also found to be beneficial, but not without serious side effects.
The panel concluded that the drug is effective, and data shows that people can lose anywhere from 6 percent to 10 percent of body weight, if taken in conjunction with a diet and exercise regimen. However, the committee was concerned about increased risk of psychiatric and cognitive issues uncovered in Vivus’ trials, and said that there was a lack of data to rule out cardiovascular risks and the drug’s potential to cause birth defects in women who become pregnant while taking it.
There were also concerns because 18 percent of participants taking a high dose withdrew from trials after experiencing mild side effects, such as tingling of the hands and feet, headache, and constipation. About 40 percent of all participants either taking high or low doses of Qnexa did not complete the study for various reasons.
The FDA usually follows the recommendation of its advisory panel, but the split vote, and some of the comments by panelists, may leave the FDA room to approve the drug.