In 2010, the U.S. Food and Drug Administration rejected three new weight loss pills. One of these drugs, Qnexa, developed by Vivus Inc. of Mountain View, Calif., combines low doses of a stimulant phentermine and the anti-seizure and migraine drug topiramate. Phentermine has long been used for short-term weight loss and topiramate has been used “off label” to treat binge eating. “Off label” use is when a drug is prescribed by a doctor for treatment of a condition that the drug was not originally approved for by the FDA.
Qnexa initially was denied FDA approval citing North American drug registry data showing that babies born to women who took topiramate had up to a 20-fold increase in cleft palates. Fast forward to the fall of 2011 and Vivus Inc. is once again seeking FDA approval for the drug that was rejected a year ago, based on investigations involving other databases that suggest that the risk for the oral birth defect is actually much lower.
In light of this new information, the FDA has agreed to let Vivus resubmit its application for limited approval for use in adults who are not likely to become pregnant.
Research conducted on Qnexa took place at 91 sites across the U.S. with 1,267 severely obese people. Study participants were given one or two doses of Qnexa or a placebo once a day during the year-long study. They were encouraged to follow a modest lifestyle modification and weight loss program that included counseling and a 500 calorie-a-day reduction. They were encouraged to increase their water intake and their physical activity.
Fifty-three percent of the placebo-treated patients remained in the study for the entire year, compared to 61 percent of the lower-dose Qnexa-treated patients and 66 percent of the higher-dose patients. Of the patients who completed the study, the average weight loss for patients on the higher dose of Qnexa was 14.4 percent of body weight, compared to 6.7 percent among patients on the lower dose and 2.1 percent among patients taking a placebo.
Another study published in the American Journal of Clinical Nutrition is a summary of weight loss over two years of use and found an average loss of about 10 percent of initial body weight. The most common side effects reported included tingling, dry mouth, constipation, and a tin taste in the mouth. Significant improvements in cardiovascular, metabolic and inflammatory risk factors were documented.
Qnexa appears to be the most effective weight loss drug since the Fen-Phen weight loss regimen. Fen-Phen was a combination of two separate drugs — fenfluramine and phentermine.
After it was linked to potentially fatal heart problems, fenfluramine was pulled from the market in the late 1990s. Last year, the FDA withdrew the diet drug Meridia from the market after 13 years, because of concerns about heart attack and stroke.
Obesity is a huge and growing medical problem, but are drugs that raise concerns of cleft palate, heart attack, stroke, and potentially fatal heart problems and result in only a 10 percent weight loss really worth the cost, financially and physically? One of the biggest concerns about any of these drugs is whether they are safe enough for patients to stay on to maintain their weight loss. Qnexa at this point, through research, has been shown to work better than other drugs, but the questions “at what cost/benefit and for how long?” cannot be ignored.
Georgia Clark-Albert is a registered dietitian and adjunct nutrition instructor at Eastern Maine Community College who lives in Athens. Read more of her columns and post questions at bangordailynews.com or email her at GeorgiaMaineMSRDCDE@gmail.com.