WILMINGTON, Mass.--(BUSINESS WIRE)--Jan. 3, 2006-- Strengthens DUSA's Position in the Dermatology Market. DUSA Pharmaceuticals, Inc.(R) (NASDAQ NMS:DUSA), developer and marketer of Levulan(R) photodynamic therapy (PDT) for the treatment of dermatological conditions such as actinic keratoses, acne and photodamage, announced today that it has signed a definitive Merger Agreement ("Merger Agreement") to acquire all of the common stock of Sirius Laboratories Inc. of Vernon Hills, Illinois in exchange for cash and common stock worth up to $30,000,000.