Contacts:

Sharon Tetlow diaDexus 408-330-5003 stetlow@diadexus.com

DIADEXUS ANNOUNCES ISSUED U.S. PATENT FOR ATHEROSCLEROSIS DIAGNOSTIC TEST

Lipoprotein-associated phospholipase A(2) (Lp-PLA2), a Novel Risk Factor for Coronary Heart Disease

Santa Clara, CA - March 21, 2001 - diaDexus announced today the issuance of a U.S. patent covering a method for the diagnosis of a patient's susceptibility to atherosclerosis using antibodies against Lp-PLA2, a novel risk factor for coronary heart disease. diaDexus has exclusively licensed this patent from GlaxoSmithKline.

Lp-PLA2, an enzyme associated with atherosclerotic plaque, was discovered by SmithKline Beecham (SB) scientists. diaDexus, through its relationship with SB, has an option to receive exclusive diagnostic rights to certain targets that SB identifies through September 2001, including targets identified through SB's collaboration with Human Genome Sciences through June 2001.

Scientists at diaDexus developed a simple blood test to measure the levels of Lp-PLA2 circulating in the blood. This test was used to conduct a study published in the October 19, 2000¹ issue of the New England Journal of Medicine in which elevated levels of Lp-PLA2 exhibited a strong correlation with cardiovascular events, such as heart attack. In addition, Lp-PLA2 was shown to be a risk factor independent of other known cardiac risk factors including low-density lipoprotein cholesterol and C-reactive protein.

Ron Lindsay, chief scientific officer of diaDexus said, "The import of this finding is twofold: one, monitoring levels of Lp-PLA2 may be a useful means of assessing the risk of heart attack, and two, lowering levels of Lp-PLA2 may offer benefit in reducing the incidence of heart attack."

"Our development of this diagnostic test builds on the significant research undertaken at SmithKline Beecham, now GlaxoSmithKline, and illustrates the value of our relationship," said Patrick Plewman, chief executive officer of diaDexus. "It allows us to develop diagnostics that may be paired with GlaxoSmithKline products." GlaxoSmithKline announced in February, 2001 that it has commenced clinical trials on SB-435495, an Lp-PLA2 antagonist.

Cardiovascular disease (CVD) is the leading cause of death in America. About half of those with coronary artery disease have no known risk factors such as high cholesterol, high blood pressure, type 2 diabetes or family history.

diaDexus is focused on translating raw genomics data into novel diagnostic and therapeutic products. diaDexus has utilized genomics and bioinformatics to identify thousands of disease-associated molecular targets. Currently diaDexus has two diagnostic product candidates in late-stage preclinical development.

diaDexus is located in Santa Clara, California. For more information, please visit the diaDexus Web site at www.diadexus.com.

1. Packard CJ, O'Reilly DSJ, Caslake MJ, et al. Lipoprotein-associated phospholipase A(2) as an independent predictor of coronary heart disease. N Eng J Med 2000; 343:1148-55.