Dainippon Sumitomo Pharma Co., Ltd. (“DSP”, TSE: 4506) and Sepracor Inc. (“Sepracor”, Nasdaq: SEPR) today announced that they have entered into a definitive agreement pursuant to which DSP will acquire Sepracor for approximately $2.6 billion through a cash tender offer of $23.00 per share, followed by a merger to acquire all remaining outstanding Sepracor shares at the same price paid in the tender offer. The tender offer price represents a 48.0% premium to Sepracor’s average stock price over the last six month period ending on September 1, and a 27.6% premium over the closing price of Sepracor’s common stock on September 1, 2009. The transaction was unanimously approved by the Boards of Directors of both companies. Upon completion of the acquisition, Sepracor will become a wholly owned subsidiary of Dainippon Sumitomo Pharma America Holdings, Inc., a wholly owned U.S. subsidiary of DSP, and will continue its operations based in Marlborough, Massachusetts and in Canada. Sepracor will retain its name, branding and intellectual property rights and continue to operate as Sepracor.