An investigational combination of drugs already approved to treat obesity, migraine and epilepsy produced up to a 10 percent weight loss in obese individuals participating in a one-year clinical trial, according to researchers at Duke University Medical Center
Appearing online in The Lancet, the study found that treatment with the controlled-release combination therapy consisting of phentermine and topiramate also achieved significant reductions in blood pressure and hemoglobin A1C. Study participants also experienced improvements in cholesterol, triglycerides and inflammatory markers, including C-reactive protein, when taking either of two doses of the combination when compared to placebo.
Currently, orlistat is the only drug available for the long-term treatment of obesity. It is marketed in prescription strength as Xenical, and available over the counter as Alli. Meta-analysis studies have shown that treatment with orlistat, at maximum strength, can lead to approximately seven-pound greater weight loss compared to treatment with placebo after one year. “The combination drug achieves about 19 pounds of weight loss relative to placebo at one year,” Gadde says.
The 56-week, phase 3 study was conducted in 93 U.S. centers with 2487 patients who had a BMI of 27-45kg/m2, and two or more co-morbidities such as diabetes or heart disease. Patients were randomly assigned to receive either a placebo or one of two low-dose drug combinations. The study tested phentermine, a short-term obesity treatment available since 1959, and topiramate, marketed under the trade name Topamax, in doses up to 400mg to treat epilepsy and prevent migraines. Patients in the study also received diet and exercise advice.