Vivus Weight-Loss Pill Qnexa Wins Backing of FDA Panel

(Updates with after-market trading in fifth paragraph.)

Feb. 22 (Bloomberg) -- Vivus Inc.'s weight-loss pill Qnexa won the backing of a U.S. advisory panel as the company seeks to gain approval for the first new obesity drug in 13 years. The shares doubled in late trading.

Advisers to the Food and Drug Administration voted 20-2 today that Qnexa's benefits outweigh its risks at a meeting at agency headquarters in Silver Spring, Maryland. The FDA isn't required to follow the panel's recommendation. The agency is due to decide on the drug, which it rejected in 2010, by April 17.

Qnexa is one of three medications vying for the first U.S. approval of a prescription weight-loss treatment since Swiss drugmaker Roche Holding AG's Xenical in 1999. The FDA plans to have advisers discuss in March the possibility of requiring heart-risk studies for all weight-loss drugs. Panel members discussed whether Vivus should conduct such a study before or after approval.

“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 Sanjay Kaul, a cardiology professor in the David Geffen School of Medicine at UCLA Cedar Sinai Medical Center and a panel member.

Vivus surged $10.55 to $21.10 at 6:58 p.m. New York time. Trading in the stock was halted during the day before the FDA panel vote.

Heart Risk Concerns

Regulators raised concerns that Qnexa may contribute to a greater risk of heart ailments and birth defects. The medicine combines the appetite suppressant phentermine with topiramate, an antiseizure and migraine drug. The Mountain View, California- based company has proposed a post-approval trial to assess Qnexa in reducing major heart complications in obese, at-risk patients. The trial would involve 11,300 patients and take four and a-half years.

Analysts say the drug, if approved, may generate $448 million in sales in 2015.

Topiramate is the active ingredient in Johnson & Johnson's Topamax. The anticonvulsant is also associated with confusion, difficulty with concentration and memory loss.

Vivus' analysis of heart risks for Qnexa was “somewhat reassuring,” though the significance of an observed increase in heart rate was “uncertain,” FDA staff said Feb. 17 in a report.

More than one-third of U.S. adults are obese, and another third are overweight, according to the Centers for Disease Control and Prevention. The obesity rate among adults has more than doubled since 1980 to 72 million people.

Obesity Risks

Obesity raises the risks of diabetes, heart attacks and stroke, and costs the U.S. economy an estimated $147 billion a year in medical expenses and lost productivity, according to the Atlanta-based CDC.

Orexigen Therapeutics Inc., based in La Jolla, California, and San Diego-based Arena Pharmaceuticals Inc. also are seeking approval for their obesity medicines, which the FDA refused to approve without more data on safety risks.

Vivus examined medical claims data and found five oral clefts in a group of 1,740 children whose mothers had taken topiramate alone in the first trimester of pregnancy, for a prevalence rate of 0.29 percent, the company said Dec. 21 in a statement. That compared with a rate of 0.16 percent in the group whose mothers had taken antiseizure drugs, including topiramate, before pregnancy.

Study Results

Vivus plans to finish the results in the third quarter of this year, after the April 17 deadline for the FDA to decide whether to approve the drug. The risk of oral clefts hasn't been fully answered by the interim data, FDA staff said.

The FDA asked Vivus in January to remove wording from Qnexa's proposed prescribing label advising women with the potential to become pregnant against taking it. The FDA staff said in the Feb. 17 report severely restricting Qnexa isn't practical because topiramate also treats other serious conditions.

Panel members suggested the FDA should consider restricting topiramate used for seizures and migraines for women of childbearing age.

“I just can't get my mind around why it would be different,” said Lamont Weide, chief of diabetes and endocrinology at the Truman Medical Centers Diabetes Center in Kansas City and a member of the panel.

Russell Katz, director of FDA's neurology products division, said the agency hasn't considered restricting the drug because there aren't many options for migraine prevention.

Vivus has suggested restricting distribution of Qnexa to less than 10 large mail-order pharmacies with pharmacists trained in dispensing the drug, Barbara Troupin, senior director of global medical affairs at the company, said.

In addition to Roche's Xenical, London-based GlaxoSmithKline Plc's Alli, a half-dose version of Xenical's active ingredient, won FDA clearance in 2007 as the first diet drug available without a prescription. 


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