Shares of biopharma stocks jumped Monday as regulatory decisions on a pair of new diet pills grow near. Arena Pharmaceuticals (ARNA) rallied 12% early. The company expects a decision from the Food and Drug Administration on lorcaserin, its experimental diet drug, on June 27. On May 10, a panel of outside experts voted 18 to 4 to recommend approval. If it wins full FDA approval, lorcaserin would be one of the first new diet drugs in more than a