Shares of Dusa Pharmaceuticals were hammered by the news that the developer is dropping development of its Levulan Photodynamic Therapy for moderate to severe acne it flunked a mid-stage trial. Its stock dropped 27 percent on the news that the therapy in combination with its BLU-U lighting-based treatment failed to demonstrate a significant response when compared to a group who received only the lighting-based treatment. Dusa release