WASHINGTON (AP) - Orexigen Therapeutics Inc. said Tuesday it is reviving its previously abandoned weight loss drug Contrave, after federal health officials outlined a plan that could bring the drug to market by 2014.
The surprise announcement returns Contrave to the race to be the first new prescription weight loss drug to reach the U.S. market in more than a decade.
Company shares leapt 95 cents, or 64.6 percent, to $2.42 in afterhours trading. The stock was trading in the $9 range before the FDA rejection of Contrave, which wiped out about two-thirds of its value.
The company said in June it would not seek U.S. approval for the highly anticipated pill because of the government's "unprecedented" demands for additional safety studies. The effort to develop weight loss drugs has been plagued by safety concerns for decades.
But the company said late Tuesday that the Food and Drug Administration has now agreed to a study which could be completed and reviewed by 2014. The study would involve 10,000 patients and take two years to gather the necessary data on heart side effects, according to the company.
"Orexigen believes that these design requirements are reasonable and feasible and provide the certainty required to reinitiate development of Contrave," the San Diego-based drugmaker said in a statement.
The FDA rejected Contrave in February because of concerns the drug could increase heart problems. Two other experimental weight loss drugs were rejected last year, raising questions of whether any new therapy for obesity could win approval in the U.S.
On a call with reporters and analysts, CEO Michael Narachi attributed the FDA's about-face to efforts by patient groups, lawmakers and the company itself.
"I think this was a multi-pronged effort that we built to create some momentum that helped the process," Narachi said.
With the U.S. obesity rate for adults nearing 35 percent, the FDA has acknowledged the need for new weight loss drugs. But the agency rejected two other drugs last year due to safety risks. Those drugs were made by fellow California drug developers Vivus Inc. and Arena Pharmaceuticals Inc. Vivus plans to resubmit its drug to the FDA next month, potentially putting it ahead of Contrave in the race to reach the market.
Contrave had been pegged as the safest of the new generation of obesity treatments because it simply combines two older, established drugs: an antidepressant and an anti-addiction drug to curb appetite. Four out of 10 patients taking Contrave for a year lost at least 5 percent of their body weight. Those results narrowly met FDA's guidelines for effectiveness.
But heart side effects have been a major concern with diet drugs, most recently with Abbott Laboratories' pill Meridia, which was removed from the market in October after studies showed it increased the risk of heart attack and stroke.
Currently there is just one prescription drug on the market for long-term weight loss: Roche's Xenical, which is not widely used. Several other generic drugs are approved for short-term weight loss, including phentermine.