During a 28-week trial, drug developer Vivus Inc. discovered their experimental drug Qnexa helped obese people lose an average of 9.2 percent of their weight, Reuters reported.

In the 756-patient study, patients who took the highest dose of Qnexa lost the most weight, compared with patients who took the drug’s individual components and those who took a mid-dose or placebo pill.

Qnexa is a combination of phentermine – half of the recalled fen-phen diet pill – and the epilepsy drug topiramate, which is marketed under Topamax. The Food and Drug Administration recalled Fen-phen because of reports that the other half of the drug’s component, fenfluramine, caused heart damage.

Vivus said Qnexa was well-tolerated and common side-effects included itching, dry mouth, altered taste and constipation.

Study participants were asked to eat no more than 500 calories a day and to exercise at least three times a week. More trials are expected in 2009 and the company hopes to file for FDA approval in late 2009.

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