CAMBRIDGE, Mass.--(BUSINESS WIRE)--ARIAD Pharmaceuticals, Inc. (NASDAQ: ARIA) announced today that it is offering to sell 16,000,000 shares of its common stock in an underwritten public offering. Jefferies & Company, Inc. and Oppenheimer & Co. are acting as joint book-running managers for the offering. ARIAD also expects to grant the underwriters a 30-day option to purchase up to 2,400,000 shares to cover over-allotments, if any.