Shares of Arena Pharmaceuticals Inc. closed 29 percent higher on June 27 after word that the Food and Drug Administration had approved its diet drug.

Arena’s drug, lorcaserin, will be sold under the name Belviq. Arena said it was the first prescription weight-loss drug to receive FDA approval in 13 years.

Arena stock opened at $9 per share and closed at $11.39, after reaching a peak of $13.50. Some 90 million shares traded hands on June 27. Arena’s Nasdaq symbol is ARNA.