FDA notes concerns about Vivus diet pill safety ahead of panel

U.S. regulators have cited concerns about the safety of Vivus’ ($VVUS) experimental diet pill Qnexa in review documents as the California drug developer pursues the first FDA approval of a weight-loss drug in more than a decade.

Vivus is taking a second shot at a market nod for the drug, which regulators rejected in 2010 because of the potential for heart problems and birth defects. The company now has come back to the table with data from a safety study and a plan to limit use of the drug in women who become pregnant. A panel of experts will weigh in Wednesday on the company’s application and vote on whether the FDA should give the developer its long-sought approval.

New obesity drugs have been a risky bet in the biopharma world because of the safety hurdles that companies must overcome. Industry watchers are keen to see how regulators treat Vivus’ latest bid for approval as a harbinger in the diet pill arena.

While there might not be burning red flags in the latest FDA review documents about new safety concerns, staffers noted: “For each weight change category, the PHEN/TPM-treated subjects had a higher increase in mean heart rate compared to placebo-treated subjects from baseline to Week 56,” according to the documents released this morning. Cardiovascular risks have plagued past obesity treatments, and the success of Qnexa could hinge on how regulators view the risks versus the benefits of the drug.

Vivus has been able to show in past studies that Qnexa can deliver weight-loss benefits for patients. In fact, as The New York Times reported this week, doctors are already prescribing the two drugs that are combined in Qnexa--phentermine and topiramate--to help patients lose weight.

About one in three Americans is considered obese, according to the Centers for Disease Control and Prevention, and the biopharma industry would love to seize this huge market opportunity by selling new weight-loss drugs. In addition to Vivus, Orexigen Therapeutics and Arena Pharmaceuticals are two notable developers in the hunt to advance new diet pills onto the U.S. market.

- here's the AP story
- see The New York Times article
- and an update from Reuters