New diet drug overwhelmingly endorsed by FDA committee

A new weight-loss medication got an overwhelming endorsement on Wednesday from FDA’s Endocrinologic and Metabolic Drugs Advisory Committee. The committee voted 20-2 in favor of approving phentermine/topiramate (Qnexa, Vivus).

Vivus submitted data showing median weight loss exceeding 10% during the first 2 years of use. Data also showed significant improvement in cardiovascular, glycemic, metabolic, and inflammatory end points.

If FDA follows its advisory committee lead, phentermine/topiramate would be the first weight loss drug to be approved since orlistat (Xenical, Genentech) came to market in 1999. If approved, the drug would be indicated for patients with a body mass index of 27 or greater with weight-related comorbidities such as hypertension, type 2 diabetes, dyslipidemia, or central adiposity. The agency is expected to issue its decision by April 17.

FDA rejected phentermine/topiramate in 2010 over concerns about increased rates of cleft lip and cleft palate birth defects and increased heart rate. The agency could require Vivus to conduct large-scale, post-marketing studies as part of its approval. More than 35% of US adults are obese and another third are overweight.

“Of all the obesity drugs, this one has the highest efficacy in terms of weight loss, so that shifts the balance in terms of requiring a post-approval study rather than a pre-approval study,” said panel member Sanjay Kaul, MD, MPH, professor of medicine at the Geffen School of Medicine at the University of California Los Angeles.

Vivus has proposed a major trial following 11,300 patients over 4.5 years to assess the effect of phentermine/topiramate on reducing major cardiovascular events in at-risk obese patients. Analysts estimate sales of $448 million in 2015 if the drug is approved.