FDA Won't Approve Weight Loss Drug Contrave

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Agency Asks for More Studies to Check for Heart Attack Risk

By Courtney Ware
WebMD Health News

Reviewed by Laura J. Martin, MD

Feb. 1, 2011 -- The FDA has decided not to approve the weight loss drug Contrave.

The agency issued a response letter that asks Orexigen Therapeutics, the maker of Contrave, to check for heart attack or other cardiovascular risks by conducting a "randomized, double-blind, placebo-controlled trial." Studies of this kind randomly assign patients to receive either a drug or a dummy pill.

In order for Contrave to be approved the study must demonstrate that Contrave's heart risks do not exceed the drug's benefits. Such a trial could take years, according to experts.

"We are surprised and extremely disappointed with the Agency's request in light of the extensive discussion and resulting vote on this topic at the December 7 Advisory Committee meeting," President and CEO of Orexigen Michael Narachi says in a news release. At that meeting, an FDA advisory committee voted 13 to 7 to recommend approval of Contrave despite its modest effectiveness in helping people lose weight.

In previous studies, people taking Contrave lost only 4.2% more of their body weight compared to those taking a placebo, which is below the FDA standard of 5%.

Series of FDA Rejections

Contrave is the third weight loss drug in recent months to be rejected. The FDA formally rejected locaserin from Arena Pharmaceuticals and Qnexa from Vivus in October 2010.

The agency has become very focused on the safety of diet drugs because of their potential widespread use by not only obese patients but by people looking to lose a small amount of weight. Nearly two-thirds of American adults are overweight or obese.

Contrave is an experimental drug that combines naltrexone, an opioid blocker used to treat addictions, and bupropion, an antidepressant, to suppress food cravings for the treatment of obesity, according to its maker.

SOURCES: News release, Orexigen Therapeutics Inc.WebMD Health News: "FDA Panel Supports New Obesity Drug Contrave."NYTimes.com.Pharmalot.com.

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