Contacts:

Patrick Plewman diaDexus 408-496-6600 pplewman@diadexus.com

Lee Parker GCI Group 415-356-9652 lparker@gcigroup.com

DIADEXUS DEVELOPS TEST FOR NOVEL, INDEPENDENT RISK FACTOR

Santa Clara, CA - October 18, 2000 - diaDexus, Inc. today reported on a study, published in the current issue of The New England Journal of Medicine¹, of a new independent risk factor for coronary heart disease (CHD). The study concluded that the enzyme, lipoprotein-associated phospholipase (Lp-PLA2), exhibited a strong correlation with risk of CHD that was independent of other known risk factors, such as low-density lipoprotein cholesterol (LDL cholesterol).

The study was led by Chris J. Packard, D.Sc., University of Glasgow, Department of Pathological Biochemistry at the Royal Infirmary. Researchers from diaDexus and SmithKline Beecham (SB) contributed to the study.

"This study describes a novel risk factor that can be used to identify and manage patients at risk of a cardiac event," said Dr. Chris Packard, the first author on the report. "The strong association between elevated Lp-PLA2 levels and cardiac events was independent of other known risk factors. Many people who suffer heart attacks have unremarkable levels of classical risk factors such as LDL cholesterol, so it is critical that new risk factors are discovered and their role in heart disease is understood."

Scientists from SB postulated a number of years ago that Lp-PLA2 might play a role in atherosclerosis2 and colleagues from diaDexus developed the assay used in the study reported in the Journal to measure the levels of Lp-PLA2 circulating in the blood. The study sought to determine whether blood levels of the enzyme correlate with coronary events in an epidemiological investigation. The finding relied upon blood samples collected during the West of Scotland Coronary Prevention Study (WOSCOPS), an earlier landmark investigation in the cardiovascular field.³

The Lp-PLA2 study examined the cases of 580 men in WOSCOPS who had suffered adverse coronary events: specifically, heart attacks, fatal heart attacks, or procedures performed to prevent heart attacks, coronary-artery-bypass surgery or angioplasty. The cases were compared with 1,160 other men from WOSCOPS who had not suffered an event. The comparison was controlled for age and smoking status. All the men were white, middle-aged and had above-normal cholesterol levels.

Examining five ranges of Lp-PLA2 levels, the study found a strong correlation (p<0.001) between Lp-PLA2 and coronary events.⁴ The risk of an event was about two times greater in the highest range than in the lowest range. Lp-PLA2 was shown to be a strong risk factor independent of LDL cholesterol and other markers of inflammation, such as C-reactive protein.

"On the formation of diaDexus, SB exclusively licensed certain intellectual property rights to diaDexus in the diagnostics field, including Lp-PLA2," said Patrick Plewman, president and chief executive officer at diaDexus. "Given the fact that 50% of individuals with coronary artery disease have normal lipid levels⁵, there is a clear need for novel risk factors. This study highlights the potential for Lp-PLA2 as a novel, independent risk factor." diaDexus intends to commercialize the assay initially as a research diagnostic kit and ultimately will seek to develop an FDA (or equivalent regulatory authority) approved diagnostic test.

diaDexus, based in Santa Clara, Calif., is dedicated to the discovery of novel biomarkers, enabling the development of products to detect and treat disease.

For more information, visit the diaDexus Web site at www.diadexus.com

SmithKline Beecham (SB) is a healthcare company based in London with US headquarters in Philadelphia, PA.

1. Packard CJ, O'Reilly DSJ, Caslake MJ, et al. Lipoprotein-associated phospholipaseA2 as an independent predictor of coronary heart disease. N Eng J Med 2000; 343:1148-55.

2. Macphee CH, Moores KE, Boyd HF et al. Lipoprotein associated phospholipase A2, platelet activating factor acetylhydrolase, generates two bioactive product during the oxidation of low density lipoprotein. Use of a novel inhibitor. Biochem J 1999; 338:479-87. 

3. Shepherd J, Cobbe SM, Ford I et al, for the West of Scotland Coronary Prevention Study Group. Prevention of coronary heart disease with pravastatin in men with hypercholesterolaemia. N Engl J Med 1995; 333:1301-7.

4. In a univariate analysis, p<0.001; in a multivariate analysis, p=0.005. See Tables 2 and 5 in the Journal paper.

5. Manson JE, Tosteson H, Ridker PM, et al. The primary prevention of myocardial infarction. N Engl J Med 1992; 326(21):1406-16.