Diadexus And Mayo Clinic Join Forces On PLAC Activity Test To Improve Patient Care For Cardiovascular Diseases

Rochester, MN and South San Francisco, CA - (Marketwire) - Diadexus, Inc. (OTCQB: DDXS), a diagnostics company developing and commercializing products that aid in the prediction of cardiac disease risk, and Mayo Clinic recently signed an agreement to collaborate in the areas of education, research, and innovation on the PLAC® Test for Lp-PLA2 Activity. The test, which has been cleared by the U.S. Food and Drug Administration, is used to help identify risk for coronary heart disease in patients with no history of cardiovascular events.

As part of the agreement, Mayo Clinic's Department of Laboratory Medicine and Pathology will participate in the Diadexus Laboratory Partnership Program, where Diadexus will provide educational support during the proper integration and use of Lp-PLA2 Activity testing in the clinical practice. Once fully integrated, the test will be available to patients and providers worldwide through Mayo Clinic's reference laboratory Mayo Medical Laboratories, which offers advanced laboratory testing and pathology services to more than 5,000 health care organizations.

"The PLAC Test for Lp-PLA2 Activity is an advanced tool that has demonstrated a unique and independent value in assessing the risk of heart attack, cardiovascular death, and the need for revascularization in patients at risk of such a first event," says Kenneth Fang, M.D., chief medical officer of Diadexus. "The collaboration with Mayo Clinic will provide valuable leadership in education and research and access to this robust new cardiovascular biomarker test."

"Research has shown that the use of lipid panel testing is often not sufficient for identifying a patient's risk for heart disease. When there is ambiguity, the measurement of Lp-PLA2 activity levels can be extremely helpful in defining those at risk," says Allan Jaffe, M.D., consultant and chair of the Division of Clinical Core Laboratory Services at Mayo Clinic, with a joint appointment in the Division of Cardiovascular Diseases. "The ability for us to integrate this assay directly into our laboratory facilities at Mayo will help us better identify those at risk and allow for appropriate interventions."

"Mayo Clinic is a leader in cardiovascular disease treatment and biomarker testing, and we are honored to work with the organization," says Lori Rafield, Ph.D., chairman and CEO for Diadexus. "This collaboration will improve patient care by providing cardiovascular patients of Mayo Clinic and clients of Mayo Medical Laboratories with a much more robust test for a clinically validated biomarker."

Dr. Allan Jaffe is a paid scientific adviser to Diadexus.

About the PLAC® Test for Lp-PLA2 Activity
The PLAC® Test for Lp-PLA2 Activity, cleared by the U.S. FDA in December 2014, is to be used in conjunction with clinical evaluation and patient risk assessment as an aid in predicting risk of coronary heart disease in patients with no prior history of cardiovascular events, a population that represents approximately 75 percent of coronary heart disease patients. Lp-PLA2 (lipoprotein-associated phospholipase A2) is a cardiovascular risk marker supported by a decade of peer-reviewed literature. Lp-PLA2 provides important new information about blood vessel inflammation, over and above the traditional risk factors measured on a lipid panel.

About Diadexus, Inc.
Diadexus, based in South San Francisco, California, is a diagnostics company developing and commercializing products that aid in the prediction of cardiac disease risk, providing health care providers with actionable information for managing patients. The company pioneered the testing of Lp-PLA2 (lipoprotein-associated phospholipase A2), a marker of vascular-specific inflammation that provides new information, over and above traditional risk factors measured in a lipid panel, and has more than a decade of peer-reviewed literature validating its utility. Diadexus' products, The PLAC® Test ELISA Kit, first cleared by the FDA in 2003, and The PLAC® Test for Lp-PLA2 Activity, cleared in December 2014, are the only two FDA-cleared tests to measure Lp-PLA2.

The company also has a pipeline of biomarkers for heart failure: proADM, proET-1, and proANP -- each providing distinct, additive information for healthcare providers over currently available markers. Diadexus also provides services to pharmaceutical partners to address the need to incorporate biomarkers in clinical development. For more information, visit the company's website at www.diadexus.com.

About Mayo Medical Laboratories/Department of Laboratory Medicine and Pathology
The Mayo Clinic Department of Laboratory Medicine and Pathology and its reference laboratory Mayo Medical Laboratories provide advanced laboratory testing and pathology services to support 5,000 health care organizations around the world. Revenue from this testing is used to support medical education and research at Mayo Clinic, a nonprofit worldwide leader in medical care, research, and education for people from all walks of life. Complemented by collaborations with diagnostic and biotechnology companies, the department maintains a robust diagnostic test-development program, launching more than 150 new tests each year.

About Mayo Clinic
Mayo Clinic is a nonprofit organization committed to medical research and education, and providing expert, whole-person care to everyone who needs healing. For more information, visit http://www.mayoclinic.org/about-mayo-clinic or http://newsnetwork.mayoclinic.org.

Forward-Looking Statements
This release contains forward-looking statements within the meaning of the Private Securities Litigation Reform Act of 1995. Any statements in this release that are not historical facts may be considered such "forward-looking statements," including statements regarding, among other things, Diadexus collaboration with Mayo Clinic, its effect on patient care, advantages of the PLAC® Tests and potential size of the addressable market. Forward-looking statements are based on current expectations and assumptions and entail various risks and uncertainties that could cause actual results to differ materially from those expressed in such forward-looking statements. Important factors known to us that could cause actual results to differ materially from those expressed in such forward-looking statements include success of Diadexus collaboration with Mayo Clinic; sales of our PLAC® Test products in the marketplace; product pricing and demand with a concentrated customer base; relationships with key customers; our ability to continue to build our heart failure franchise; our ability to identify and build products with additional biomarkers; third-party payors' acceptance of and reimbursement for the PLAC® Tests; our ability to continue to manufacture the PLAC® Tests to meet customer demand; the potential for success of and timing of when our development efforts may be completed; the adequacy of our intellectual property rights and our ability to maintain a proprietary position for our lead product; our limited revenue and cash resources; our significant corporate expenses, including real estate lease liabilities and expenses associated with being a public company; our ability to develop proADM for regulatory submission. Additional factors that could cause our results to differ materially from those described in the forward-looking statements can be found in our most recent annual report on Form 10-K, quarterly report on Form 10-Q, and other reports filed with the Securities and Exchange Commission (SEC), and available at the SEC's website at www.sec.gov. The information set forth herein speaks only as of the date hereof, and except as required by law, we disclaim any intention and do not assume any obligation to update or revise any forward-looking statement, whether as a result of new information, future events, or otherwise.