Exact Sciences Advances Development of Non-Endoscopic Oncoguard Esophagus Test to Screen for Esophageal Cancer and Pre-Cancer

Exact Sciences Corp. (Nasdaq: EXAS), a leading provider of cancer screening and diagnostic tests, in collaboration with Mayo Clinic Comprehensive Cancer Center, reported on data showing high sensitivity and specificity for the non-endoscopic Oncoguard Esophagus test that is currently in development for the detection of esophageal adenocarcinoma (EAC) and its precursors, including Barrett’s esophagus (BE).^1,2 Findings from the test’s algorithm training and testing were recently published in the Clinical Gastroenterology and Hepatology journal.

EAC is the most common form of esophageal cancer in the U.S. with incidence having increased significantly over the past few decades compared to other, more common types of cancer where rates have either declined or remained flat due to advanced technologies in screening.^3,4 The majority of EAC cases are diagnosed in advanced stages, with early EAC typically having no signs or symptoms, making screening in high-risk populations a critical need.⁵ There are approximately 30 million people in the U.S. who are at high-risk for EAC and should be screened.⁶

“Esophageal adenocarcinoma (EAC) is quickly becoming one of the deadliest cancers, with over 80% of patients dying within five years of diagnosis.⁷ Barrett’s esophagus (BE) is the only known precursor to EAC and patients with BE have an increased risk of progressing to EAC if not caught early. Standard methods of screening can be invasive and costly for patients, which is why there has been a recent push to change the screening guidelines to include non-endoscopic tests,” said Prasad G. Iyer, MD, Professor of Medicine, Division of Gastroenterology and Hepatology, Mayo Clinic Comprehensive Cancer Center. “In collaborating with Exact Sciences, we are able to study the potential of a minimally invasive, non-endoscopic screening tool currently in development in patients at higher risk for EAC. Our algorithm training and testing study accomplishes the next critical step for the accurate, non-endoscopic detection of BE/EAC.”

The study used an encapsulated sponge collection device to collect esophageal specimens from 352 participants in the training set and 125 participants in the test set. These were then blindly assayed for methylated DNA markers (MDMs). Cross-validation of the three-MDM panel demonstrated an overall sensitivity of 82% (CI, 68% to 94%) for BE detection at 90% specificity (CI, 79% to 98%) in the training set and 88% sensitivity (CI, 78% to 94%) at 84% specificity (CI, 70% to 93%) in the test set. In both training and test sets, sensitivity was 100% for EAC and BE with high grade dysplasia (HGD) – both treatment-eligible subsets. The collection method was generally well tolerated by study participants and was conducive to office-based implementation.