The Corus(R) CAD Gene Expression Test Significantly Correlates With Plaque Burden and Obstructive Coronary Artery Disease as Validated by CT-Angiography

PALO ALTO, CA--(Marketwired - Feb 3, 2014) - CardioDx, Inc., a molecular diagnostics company specializing in cardiovascular genomics, today announced the publication of a new analysis demonstrating that the Corus CAD gene expression score is significantly associated with plaque burden and luminal stenosis in symptomatic patients being evaluated for obstructive coronary artery disease (CAD), as measured by CT-angiography. The study, "A Peripheral Blood Gene Expression Score is Associated with Atherosclerotic Plaque Burden and Stenosis by Cardiovascular CT-Angiography," appears online in the journal Atherosclerosis on February 2014.

"Our understanding of the relationship between peripheral blood gene expression, as measured by the Corus CAD gene expression score, and plaque composition and stenosis determined by CT-angiography continues to grow," said Steven Rosenberg, Ph.D., senior author and a member of CardioDx's Scientific Advisory Board. "These findings are important as they show that the Corus CAD score, which provides an estimate of a patient's likelihood of obstructive CAD, offers additional information related to disease burden that is useful in the diagnostic evaluation of the patient."

In this subgroup analysis, which included 610 patients from the PREDICT and COMPASS studies, the Corus CAD gene expression score was significantly associated with plaque burden (p < 0.001) and luminal stenosis (p < 0.01) as measured by CT-angiography. Additionally, the Corus CAD gene expression score was a stronger predictor of stenosis, as compared to the Diamond-Forrester clinical classification. Furthermore, an increasingly higher Corus CAD gene expression score was associated with increasing maximal stenosis, as determined by CT-angiography (p < 0.001).

About Obstructive Coronary Artery Disease

Coronary artery disease is a very common heart condition in the United States. One in six deaths among Americans is caused by CAD.¹ CAD can cause a narrowing or blockage of the coronary arteries (vessels to the heart that supply the heart with blood, oxygen, and nutrients), reducing blood flow to the heart muscle. This narrowing or blockage in the coronary arteries is often referred to as obstructive CAD, characterized by the presence of atherosclerosis, or plaque.

About Corus CAD

Corus CAD is a blood test that can safely, accurately and conveniently help primary care clinicians and cardiologists assess whether or not a stable non-diabetic patient's symptoms are due to obstructive CAD, enabling many patients to avoid unnecessary noninvasive and invasive cardiac procedures and exposure to imaging-related radiation risks, imaging agent intolerance or complications with cardiac catheterization. The test involves a routine blood draw that is conveniently administered in the clinician's office. The test is simple, convenient, and as a sex-specific test for the diagnosis of obstructive CAD, accounts for critical biological differences between men and women.

The test has been clinically validated in independent patient cohorts, including two prospective, multicenter U.S. studies, PREDICT and COMPASS.^2,3 In the COMPASS study, Corus CAD outperformed myocardial perfusion imaging (MPI) in diagnostic accuracy as a test to exclude obstructive CAD, demonstrating a significantly higher sensitivity (89% vs. 27%, p < 0.001) and a significantly higher negative predictive value (96% vs. 88%, p < 0.001) than MPI for assessing the presence of obstructive CAD. Over 55,000 Corus CAD test results have been commercially delivered to clinicians. Corus CAD is a covered benefit for the estimated 48 million Medicare beneficiaries in the U.S. CardioDx processes all Corus CAD test samples at its CLIA-certified and CAP-accredited clinical laboratory in Palo Alto, Calif.

About Gene Expression

Corus CAD is a gene expression test, not a genetic test. Whereas genetic testing may inform on lifetime disease risk, the Corus CAD gene expression test provides a current-state assessment of obstructive CAD by looking at the gene expression changes associated with atherosclerosis. Gene expression levels change depending on a person's disease status resulting from genetic and environmental factors.

About CardioDx

CardioDx, Inc., a molecular diagnostics company specializing in cardiovascular genomics, is committed to developing clinically validated tests that empower clinicians to better tailor care to each individual patient. Strategically focused on coronary artery disease, cardiac arrhythmia and heart failure, CardioDx is committed to expanding patient access and improving healthcare quality and efficiency through the commercialization of genomic technologies. For more information, please visit www.cardiodx.com.

Forward-Looking Statements

This press release may contain forward-looking statements, including statements regarding the safety and efficacy of and the size of the market for Corus CAD and beliefs regarding the need for and value of gene expression diagnostics. These statements relate to future events and involve known and unknown risks, uncertainties and other factors that could cause actual levels of activity, performance or achievement to differ materially from those expressed or implied by these forward-looking statements. These statements reflect the views of CardioDx as of the date of this press release with respect to future events and, except as required by law, it undertakes no obligation to update or revise publicly any forward-looking statements, whether as a result of new information, future events or otherwise after the date of this press release.

¹ Go AS, Mozaffarian D, Roger VL, et al. Heart Disease and Stroke Statistics--2013 Update: A Report From the American Heart Association. Circulation. 2013;127:e6-e245.
² Rosenberg S, Elashoff MR, Beineke P, et al. Multicenter Validation of the Diagnostic Accuracy of a Blood-Based Gene Expression Test for Assessing Obstructive Coronary Artery Disease in Nondiabetic Patients. Ann Intern Med. 2010;153:425-434.
³ Thomas GS, Voros S, McPherson JA, et al. A Blood-Based Gene Expression Test for Obstructive Coronary Artery Disease Tested in Symptomatic Nondiabetic Patients Referred for Myocardial Perfusion Imaging: The COMPASS Study. Circ Cardiovasc Genet. 2013;6:154-162.