Vivus said the 28-week, 756-patient study met its main goal of superior weight loss with two different doses of Qnexa, compared with the drug's individual components and a placebo pill. Patients in the placebo group on average lost 1.7% of their weight, while patients on "mid-dose" Qnexa lost 8.5%.

Qnexa is a combination of phentermine - half of the recalled fen-phen diet pill - and the epilepsy drug Topamax, or topiramate. Timothy Morris, Vivus' chief financial officer, said weight loss results for the two components were also significantly better than placebo and will be disclosed at a meeting with analysts and investors.

Vivus said 66% of patients treated with full-dose Qnexa achieved weight loss of 5% or more. The company said Qnexa was well-tolerated - the most common side effects were itching, dry mouth, altered taste and constipation.

How the study was done
Reported drug-related adverse events for depression and altered mood were 1.9 percent for full-dose Qnexa, 0.9% for the mid-dose and 1.8% for placebo patients.

Patients in the trial were asked to restrict calories by 500 a day and advised to exercise three times a week. Morris said Vivus expects results in mid-2009 from two larger phase III trials of Qnexa and plans to file for US Food and Drug Administration approval late next year.

He also said the company will begin to assess partnering opportunities once it has the data from the year-long studies in hand. Vivus is also studying Qnexa as a treatment for diabetes, but Morris said the company needs to conduct a study of how the drug compares with phentermine and topiramate before it can launch a phase III diabetes trial. – (Reuters Health, December 2008)