LEXINGTON, Mass. & SEATTLE--(BUSINESS WIRE)--Cubist Pharmaceuticals, Inc. (NASDAQ: CBST) and Illumigen Biosciences, Inc. announced today that they have signed an agreement under which Cubist has an exclusive option to acquire Illumigen on terms that have been agreed to by the parties. For the option, Cubist will pay $4.7 Million and also will pay approximately $1 Million for an IND-enabling study of Illumigen’s lead compound, IB657, and for Illumigen’s operating costs during the option period. IB657 is a protein therapeutic in late-stage pre-clinical development as an interferon replacement product for the treatment of Hepatitis C virus (HCV) infections.