FDA Reconsiders Weight Loss Drug Qnexa
Weight Loss Impressive, but Safety Questions Remain
WebMD News Archive
‘Most Effective Drug Since Fen-Phen’
The newly published study included 1,267 severely obese people treated at 91 sites across the country.
Study participants took one of two doses of Qnexa or a placebo once a day during the year-long study. All were advised to follow a modest lifestyle modification/weight loss program that included counseling and a 500 calorie-a-day reduction, increased water intake, and increased physical activity.
Fifty-three percent of the placebo-treated patients remained in the study for the entire year, compared to 61% of the lower-dose Qnexa-treated patients and 66% of the higher-dose patients.
The most commonly reported side effects were tingling, dry mouth, constipation, and a tinny taste in the mouth.
At the end of the study, average heart rate increased by one beat per minute in the higher-dose Qnexa-treated patients and by less than one beat per minute in the lower-dose patients.
Diabetes specialist and study co-researcher W. Timothy Garvey, MD, of the University of Alabama at Birmingham, says based on the research 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. Fenfluramine, which was linked to potentially fatal heart problems, was pulled from the market in the late 1990s.
Among patients who completed the study:
- The average weight loss for patients on the higher dose of Qnexa was 14.4% of body weight, compared to 6.7% among patients on the lower dose and 2.1% among patients taking a placebo.
- 48% of those in the higher-dose group lost 15% or more of their body weight, compared to 12% in the lower-dose group and 6% in the placebo group.
Sixteen percent of patients treated with the highest dose of the experimental combination drug dropped out of the study early because of the side effects, compared to 11% of patients in the lower-dose group and 8.4% of people who got the placebo treatments.
Tough Times for Weight Loss Drugs
Tam says he is optimistic that Qnexa will be approved. But he acknowledges that the regulatory climate for weight loss drugs has been stormy of late.