WASHINGTON -- The Food and Drug Administration has approved Arena Pharmaceutical's anti-obesity pill Belviq, the first new prescription drug for long-term weight loss to enter the U.S. market in over a decade.
Despite achieving only modest weight loss in clinical studies, the drug appeared safe enough to win the FDA's endorsement, amid calls from doctors for new weight-loss treatments.
The agency cleared the pill for adults who are obese or are overweight with at least one medical complication, such as diabetes or high cholesterol.
The FDA denied approval for the drug in 2010 after scientists raised concerns about tumors that developed in animals studied with the drug. The company resubmitted the drug with additional data earlier this year, and the FDA said there was little risk of tumors in humans.
Arena and its partner Eisai Inc. of Woodcliff Lake, N.J., expect to launch the drug in early 2013.
With U.S. obesity rates nearing 35 percent of the adult population, many doctors have called on the FDA to approve new weight-loss treatments.
But a long line of prescription weight-loss offerings has been associated with safety problems, most notably the fen-phen combination, which was linked to heart-valve damage in 1997. The cocktail of phentermine and fenfluramine was a popular weight-loss combination prescribed by doctors, though it was never approved by the FDA.
The agency said the new drug acts on a chemical pathway in the brain that is thought to reduce appetite by boosting feelings of satiety and fullness.
Even if the effects of Belviq are subtle, experts say it could be an important first step in a new line of treatments.
"You have some people who do extremely well and other people don't lose any weight at all. But if we had 10 medicines that were all different and worked like this, we would have a real field," said Dr. Louis Aronne, director of the weight-loss program at Weill Cornell Medical College.
Belviq is one of three weight-loss drugs whose developers have been trying for a second time to win approval, after the FDA shot them down because of potential side effects.
Vivus Inc.'s Qnexa is thought to be the most promising. But the FDA has delayed a decision on that pill until July.