PALO ALTO, Calif., November 15, 2011 – CardioDx, a pioneer in the field of cardiovascular genomic diagnostics, announced results of its COMPASS (Coronary Obstruction Detection by Molecular Personalized Gene Expression) trial, which were presented today at the American Heart Association Scientific Sessions 2011 conference in Orlando, Fla. This prospective, blinded multi-center study was designed to provide a third independent validation of the Corus® CAD blood-based gene expression test for ruling out obstructive coronary artery disease in lower-risk patients with typical and atypical presentations of stable chest pain, and to compare the diagnostic performance of Corus CAD to myocardial perfusion imaging (MPI), a common test that uses a radioactive agent to evaluate the blood flow and function of the heart.
"COMPASS builds on previous results of the PREDICT trial. In this real-world patient population, the Corus CAD test demonstrates very high sensitivity and negative predictive value, enabling clinicians to rule out patients who do not have obstructive coronary artery disease with high accuracy," said Gregory S. Thomas, M.D., M.P.H., clinical professor of medicine and director of nuclear cardiology education at the University of California-Irvine School of Medicine, who presented the findings. "The use of this gene expression test, followed by MPI for higher scores, may optimize diagnostic performance and utilization of health care resources." COMPASS enrolled 537 stable patients with symptoms suggestive of coronary artery disease who had been referred to MPI at 19 U.S. sites. A blood sample was obtained in all patients prior to MPI, and Corus CAD gene expression testing was then performed, with study investigators blinded to Corus CAD test results. Following MPI, patients were referred either to invasive angiography or to CT angiography (CTA), gold-standard measurements of blood vessel lumen anatomy for diagnosis of coronary artery disease. A total of 431 patients were eligible for analysis, having completed gene expression testing, MPI and either invasive angiography or CTA. In the COMPASS study, Corus CAD was superior to MPI in diagnostic accuracy, sensitivity (89 percent vs. 27 percent, p<0.001) and negative predictive value (96 percent vs. 88 percent, p<0.001) and demonstrated excellent performance for ruling out obstructive coronary artery disease relative to both invasive angiography and CTA. "Chest pain symptoms account for two percent of all visits to the doctor’s office each year," said Mark Monane, M.D., chief medical officer of CardioDx. "Corus CAD has now been validated in more than 1,100 patients in three separate studies. For physicians, methods to improve the diagnosis of symptoms suggestive of coronary artery disease represent a huge unmet need, and the Corus CAD test may help clinicians make better decisions. For patients, the test may lead to better diagnostic accuracy as well as avoidance of unnecessary procedures. For payers, we believe that Corus CAD can address a major expense category." A study published in the March 11, 2010 issue of The New England Journal of Medicine found that in nearly 400,000 patients who underwent elective invasive angiographic procedures, 62 percent were found to have no obstructive coronary artery blockage. The study authors concluded that current modalities for identifying which patients should undergo elective invasive coronary angiography to diagnose coronary artery disease have limitations, and that better methods are needed for patient risk stratification.