The drug works to control the appetite through receptors in the brain and was approved as additional therapy for certain overweight and obese patients, combined with diet and exercise.
Trials showed the drug helped people lose an average of three to 3.7 percent of their body weight after a year when compared to a placebo, the US Food and Drug Administration said.
It is approved for use in obese adults with a body mass index of 30 or greater, or overweight adults with a BMI of 27 or greater who have at least one other condition such as high blood pressure, type 2 diabetes, or high cholesterol.
Arena’s stock opened the day at $9 per share and jumped as high as 47 percent on news of the US approval. The company said it is also seeking approval on the European market, but has no timeline yet for a decision.