WASHINGTON (Dow Jones)--A federal advisory panel Tuesday backed the use of a proposed weight-loss drug from Orexigen Therapeutics Inc. (OREX), saying potential safety concerns could be addressed in a clinical study after approval.
Shares more than doubled in value once after-hours trading resumed. The stock recently was up 150% at $12.15.
The panel of medical experts voted 13 to 7 that the benefits of the drug, Contrave, outweighed its potential risks. The vote amounts to a recommendation that the Food and Drug Administration approve the product.
The agency has a deadline of late January to make a decision, although FDA could delay the decision while details of a follow up clinical study are worked out. The FDA isn't required to follow the advice of its advisory panels but usually does.
Contrave, which is being developed with Takeda Pharmaceutical Co. (TKPYY, 4502.TO), is a combination of two drugs already on the market, addiction-treating naltrexone and the antidepressant bupropion, commonly known by the brand name Wellbutrin.
The FDA said Contrave modestly raises blood pressure in some patients and that the long-term cardiovascular risk is unclear and the panel was asked to vote on whether it thought a study looking at cardiovascular risk should be conducted before or after approval the drug. The panel voted 11 to 8, with one person abstaining, that such a study could be conducted post-market.
The agency said given the size and duration of Contrave studies, which lasted about a year and involved about 4,500 patients, the number of cardiac events was too small to make "reliable inferences about [Contrave's] effect on cardiovascular risk." The agency said it was in the early stages of discussing a study with Orexigen that would look at cardiovascular risks. An agency official told the advisory panel the study would be required if the drug were to be approved.
"We at Orexigen are not unaware of the challenges by those facing approval of obesity products," said Dawn Viveash, a senior vice president of the company.
Indeed, some panel members expressed concerns that the amount of weight loss seen among patients taking Contrave was modest. The drug met one FDA effectiveness standard but not a second measure, although only one is needed for FDA approval.
John Buse, a prominent diabetes researcher at the University of North Carolina who raised concerns about the safety of the diabetes drug Avandia several years ago, spoke on behalf of Orexigen, and said "a post approval study is appropriate and the only way to move forward."
Other company representatives noted that two ingredients in Contrave have been on the market for 20 years and haven't shown major cardiovascular safety problems.
Eric Colman, deputy director of FDA's division of metabolism and endocrinology products, said one of the main questions the agency was struggling with was whether to require a cardiovascular outcomes study before or after approval.
The agency has struggled with safety problems with diet drugs for several years most notably 13 years ago, when the two diet drugs that made up the famous fen-phen combination were linked to heart-valve damage and to a rare but potentially deadly lung disease.
In October, FDA asked Abbott Laboratories to pull its weight loss Meridia off the market saying "very modest weight loss" seen with the drug didn't justify its risk of heart attack or stroke.
The same month the FDA agency declined to approve proposed weight loss drugs from Arena Pharmaceuticals Inc. (ARNA) and Vivus Inc. (VVUS).
The FDA has expressed concerns about the side effects of obesity medicines, especially because millions of people could use the pills indefinitely.
Shares of Arena and Vivus jumped 15% and 11%, respectively, after hours. Analysts had suggested a pre-approval study requirement of Contrave's cardiovascular risks would open the door to such a requirement for all obesity drugs. The stocks of all three companies have been volatile this year, vacillating whenever one of their drugs hit a new hurdle or marked a new victory.
--By Jennifer Corbett Dooren, Dow Jones Newswires; 202-862-9294; firstname.lastname@example.org
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(END) Dow Jones Newswires
December 07, 2010 19:06 ET (00:06 GMT)
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