Ardea Biosciences Announces Proposed Public Offering of Common Stock

There can be no assurance as to whether or when the offering may be completed, or as to the actual size or terms of the offering.

Jefferies & Company, Inc. is acting as sole book-running manager for the offering. Cowen and Company, LLC, Lazard Capital Markets LLC, Leerink Swann LLC, Oppenheimer & Co. Inc. and Wells Fargo Securities, LLC are co-lead managers for the offering. JMP Securities LLC and Mizuho Securities USA Inc. are co-managers for the offering.

The securities described above are being offered by Ardea pursuant to a shelf registration statement previously filed with the Securities and Exchange Commission (the "SEC"), which the SEC declared effective on January 12, 2012. A preliminary prospectus supplement related to the offering will be filed with the SEC and will be available on the SEC's website located at http://www.sec.gov. Copies of the preliminary prospectus supplement and the accompanying prospectus relating to this offering, when available, may be obtained from Jefferies & Company, Inc., Attention: Equity Syndicate Prospectus Department, 520 Madison Avenue, 12th floor, New York, NY 10022, or by telephone at 877-547-6340, or by email at Prospectus_Department@Jefferies.com.