LEXINGTON, Mass.--(BUSINESS WIRE)--May 31, 2006--Cubist Pharmaceuticals, Inc. (Nasdaq: CBST - News) today announced it has priced $325 million of its 2.25% Convertible Subordinated Notes due 2013 pursuant to a registration statement filed with the Securities and Exchange Commission. In addition, Cubist has granted the underwriters an option to purchase up to an additional $25 million aggregate principal amount of notes. The notes will be convertible into shares of Cubist’s common stock at an initial conversion rate of 32.4981 shares per $1,000 principal amount of notes, which is equivalent to an initial conversion price of approximately $30.77 per share. The notes will bear interest at an annual rate of 2.25%. The notes will mature on June 15, 2013. The notes may not be redeemed prior to June 20, 2011 and may thereafter be redeemed by Cubist at par if the closing sale price of Cubist’s common stock for at least 20 trading days in any 30 consecutive trading day period exceeds 150% of the conversion price. The transaction is expected to close on June 6, 2006. The closing is subject to customary closing conditions.