Qnexa approval may pave way for another anti-obesity drug

An FDA advisory committee's endorsement of the anti-obesity drug Qnexa on Wednesday could reenergized the pharmaceutical industry after several years of disappointment in trying to develop anti-obesity drugs.

The committee voted 20 to 2 to recommend approval of Qnexa, which is a combination of two existing drugs, the appetite suppressant phentermine and the anti-seizure medication topiramate.

The FDA will issue its decision by April 17. Qnexa received a "no" vote in its first attempt to gain FDA approval in 2010.

If approved this time around, Qnexa would be the first new prescription weight-loss medication since 1999. Only one other medication, Orlistat, is on the market. Several other anti-obesity medications have failed to pass muster with the FDA and the drug Meridia was taken off the market in 2010 following studies that found an increased risk of serious heart problems.

Several anti-obesity drugs remain in the pipeline, however. How they fare before the FDA may hinge on a meeting next month in which agency officials and pharmaceutical industry experts will discuss how to assess anti-obesity drugs for cardiovascular safety. Several potential medications for obesity and other metabolic diseases have foundered because they raise the risk of heart problems even while causing weight loss.

Regulators must decide how much proof that a new drug won’t cause heart attacks, strokes or deaths is necessary. Qnexa will likely be approved with a requirement to conduct a post-marketing study to assess cardiovascular risks.

However, Orexigen, the maker of another drug in the pipeline, Contrave, is set to begin a 10,000-person clinical trial to demonstrate that the medication does not cause major cardiovascular events, such as heart attacks and stroke.

An FDA advisory committee voted in 2010 to approve Contrave, but the FDA turned down the application and asked for more study because the drug increased blood pressure. Earlier this month, Orexigen announced it would begin the study in the second quarter of 2012.

Contrave, like Qnexa, is a combination of medications -- buproprion, which is used for tobacco cessation, and naltrexone, which is used to relieve some of the cravings involved in recovery from alcohol and opioid dependence. The blended drug works by suppressing appetite and speeding up metabolism.

An FDA advisory committee also voted against another anti-obesity medication, Arena Pharmaceutical’s lorcaserin (or Lorqess) in 2010. That medication, also an appetite suppressant, has been linked to an increased risk of heart-valve problems but also failed to impress the panel with clinical-trial data showing only modest weight loss.

Arena also has not given up. Company officials have been working with the FDA on how best to resolve outstanding questions regarding safety and effectiveness.

Doctors who treat obesity complain that FDA hurdles have soured the pharmaceutical industry on developing anti-obesity drugs. The industry has had to weigh its troubled history with such drugs against the fact that two-thirds of American adults are overweight or obese and that a good medication would likely become a blockbuster.