RDEA Ardea Biosciences, Inc. (MM)

Ardea Biosciences, Inc. (Nasdaq:RDEA) today announced that the Company will present data from preclinical studies of RDEA119, its lead mitogen-activated ERK kinase (MEK) inhibitor in development for the treatment of cancer, demonstrating synergy when administered in combination with multiple anti-cancer agents, at the American Association for Cancer Research 100th Annual Meeting 2009 in Denver, Colorado.

Presentation Details are as follows: � Date/Time: Tuesday, April 21, 2009 from 8:00 AM � 12:00 PM Mountain Time Session Title: Kinase Inhibitors 2 Poster Title: The Selective MEK Inhibitor RDEA119: Synergy with Multiple Classes of Anti-Cancer Agents Abstract Number: 3700 Location: Hall B-F, Poster Section 35 �

About RDEA119

RDEA119, a non-ATP competitive, highly-selective MEK inhibitor for the potential treatment of cancer and inflammatory diseases is the Company's lead compound from its MEK inhibitor research and development program. RDEA119 has shown potential as a potent inhibitor of MEK, which is believed to play an important role in cancer cell proliferation, apoptosis and metastasis as well as inflammation. Preclinical and clinical results suggest that RDEA119 has favorable properties, including oral dosing, excellent selectivity and limited retention in the brain, which, in turn, may result in a reduced risk of central nervous system (CNS) side effects. RDEA119 is currently being evaluated in a Phase 1/2 study in combination with sorafenib (Nexavar�, Onyx Pharmaceuticals, Bayer HealthCare) and as a single agent in a Phase 1 study, both in advanced cancer patients.

About Ardea Biosciences, Inc.

Ardea Biosciences, Inc., of San Diego, California, is a biotechnology company focused on the discovery and development of small-molecule therapeutics for the treatment of gout, human immunodeficiency virus (HIV), cancer and inflammatory diseases. We have five product candidates in clinical trials and others in preclinical development and discovery. Our most advanced product candidate is RDEA806, a non-nucleoside reverse transcriptase inhibitor (NNRTI), which has successfully completed a Phase 2a study for the treatment of patients with HIV. We have evaluated our second-generation NNRTI for the treatment of HIV, RDEA427, in a human micro-dose pharmacokinetic study and have selected it for clinical development based on a plasma half-life of greater than 40 hours. RDEA594, our lead product candidate for the treatment of hyperuricemia and gout, is being evaluated in Phase 1 clinical trials. We are evaluating our lead MEK inhibitor, RDEA119, in a Phase 1/2 study in combination with sorafenib (Nexavar�, Onyx Pharmaceuticals, Bayer HealthCare) and as a single agent in a Phase 1 study, both in advanced cancer patients, and have completed a Phase 1 study in normal healthy volunteers as a precursor to trials in patients with inflammatory diseases. Lastly, we have evaluated our second-generation MEK inhibitor for the treatment of cancer and inflammatory diseases, RDEA436, in a human micro-dose pharmacokinetic study and have selected it for clinical development.

Statements contained in this press release regarding matters that are not historical facts are "forward-looking statements" within the meaning of the Private Securities Litigation Reform Act of 1995. Because such statements are subject to risks and uncertainties, actual results may differ materially from those expressed or implied by such forward-looking statements. Such statements include, but are not limited to, statements regarding our plans and goals, the expected properties and benefits of RDEA806, RDEA594, RDEA427, RDEA119, RDEA436 and our other compounds and the timing and results of our preclinical, clinical and other studies. Risks that contribute to the uncertain nature of the forward-looking statements include risks related to the outcome of preclinical and clinical studies, risks related to regulatory approvals, delays in commencement of preclinical and clinical studies, costs associated with our drug discovery and development programs, and risks related to the outcome of our business development activities. These and other risks and uncertainties are described more fully in our most recently filed SEC documents, including our Annual Report on Form 10-K and our Quarterly Reports on Form 10-Q, under the headings "Risk Factors." All forward-looking statements contained in this press release speak only as of the date on which they were made. We undertake no obligation to update such statements to reflect events that occur or circumstances that exist after the date on which they were made.