Qnexa, a prescription diet drug from Vivus, was recently denied approval by the Food and Drug Administration (FDA). This is the second time that the FDA's advisory committee has rejected the drug's authorisation, the first time being last July.

The FDA has asked Vivus to provide additional studies exploring whether the drug could cause birth defects, and to quantify the risks of such potential defects. The company has also been asked to research whether the drug plays a role in slightly raising the heart rate, which would increase users' risk of cardiovascular problems, such as heart attacks and strokes.

The Company's Chief Executive, Leland Wilson, stated that there is adequate existing data that will address the FDA's concerns.

Vivus, which is based in Mountain View, California, has conducted a two-year study using 4,323 participants that took the diet medicine. These men and women showed no increase in cardiovascular risk when compared to those taking a placebo. The data also showed a total body weight loss average of 10% in those taking Qnexa, which is a combination of the existing drugs phentermine and topiramate.

Mr. Wilson has not expressed concern over the FDA's rejection, believing that it is just taking the necessary measures to ensure that the drug is used for the right patients. The FDA, Mr. Wilson stated, is well aware of the fact that obesity is the leading cause of hypertension, Type 2 diabetes and many more health problems.