A drug, brand name Qnexa, reversed type 2 diabetes in 15% of patients studied over a year of treatment.

The drug is  a controlled-release combination of phentermine, an appetite suppressant, and topiramate, an anticonvulsant. Last year, the FDA rejected the drug submitted by  Vivus, the parent company. The FDA requested that Vivus provide a thorough evaluation of the drug’s potential for causing birth defects and heart problems.

A phase 3 study, published in November 2011, shows that the drug  shows a 14.4% weight loss in severely obese  patients throughout a one year timeframe. The weight loss was shown to be accompanied with improvements in cardio-metabolic risk factors.

A phase 2 study of Qnexa for treatment of type 2 diabetes demonstrated a significant reduction in HbA1c from baseline as well as improvements in blood pressure, triglycerides, and waist circumference. The most commonly reported adverse events were tingling, nausea, upper respiratory tract infection, diarrhea, and constipation.

Last month, Vivus resubmitted the New Drug Application for Qnexa and the FDA is currently reviewing it. A decision on the approval is expected in April 2012.