U.S. health regulators on Wednesday approved Arena Pharmaceuticals Inc's pill to treat obesity, making it the first new weight-loss drug in 13 years as public health advocates push for new solutions to the nation's growing obesity epidemic.

Arena's lorcaserin, which will be sold under the brand name Belviq, was one of three experimental weight-loss drugs seeking Food and Drug Administration approval after initial rejections by the agency. Vivus Inc and Orexigen Therapeutics Inc are still hoping to bring their medicines to market.

The Arena drug is approved for use in adults with a body mass index (BMI) of 30 or greater, which is considered obese, or adults with a BMI of 27 or greater -- overweight -- and who have at least one weight-related health condition, such as high blood pressure, type 2 diabetes, or high cholesterol. BMI is a measure of body fat relative to a person's height and weight.

As part of the approval, Arena will be required to conduct six postmarketing studies, including a long-term heart study to assess whether Belviq increases the risk of heart attack or stroke, the agency said in announcing its decision.

Arena's shares were halted prior to the announcement and had yet to resume trading.

Shares of Vivus, which is expecting an FDA decision on its weight loss drug next month, rose more than 9 percent following the Belviq approval. Orexigen, which is conducting a heart safety study of its obesity pill as a condition of approval, saw its shares jump more than 24 percent. (Reporting by Bill Berkrot in New York and Anna Yukhananov in Washington; Editing by Maureen Bavdek and Jim Marshall)