Exact Sciences will enroll patients at 60 sites in the US and in Canada to conduct the pivotal trial for its Cologuard multi-analyte molecular screening test for colorectal cancer.
Data from the trial, which began enrolling patients on June 30, will be submitted to the US Food and Drug Administration to support Exact Sciences' premarket approval application for the test, analyzes stool DNA for methylation markers and mutation markers associated with colorectal cancer.
The company is planning to enroll more than 10,000 patients, between ages 50 and 84, at average risk of colorectal cancer. In the trial, called the Multi-Target Colorectal Cancer Screening Test for the Detection of Colorectal Advanced Adenomatous Polyps and Cancer, or DeeP-C study, every patient will be screened for colorectal cancer, first by the Exact Sciences molecular screening test, and then by the gold standard colonoscopy.
The primary endpoint of the prospective DeeP-C study is to determine the sensitivity and specificity of the multi-marker, stool-based screening test for colorectal cancer, using colonoscopy as the reference method. In the study, researchers will confirm whether patients' lesions are malignant by histopathologic examination.
Participants deemed to be at average risk of colorectal cancer will have to provide written consent in order to participate in the study and will receive a stool collection kit. Stool samples will be analyzed by Cologuard and with a commercially available fecal immunochemical test. Within 90 days of enrollment, study participants will undergo colonoscopy. The results of the Exact Sciences' test and the FIT test will not be reported to subjects and physicians, and will not be used in the management of patients.
The company expects the DeeP-C study to take between 12 months and 15 months, and projects a PMA submission in 2012.
If Cologuard clears FDA, Exact Sciences plans to market it to primary care physicians as a complement to colonoscopy; the test is not meant to replace colonoscopy. The company has started discussions with payors about potential studies that it would need to conduct to prove the clinical utility of the CRC screening test, but there is currently nothing planned in this regard.
As previously reported by PGx Reporter sister publication GenomeWeb Daily News, the company told investors at the Jefferies Healthcare Conference that Cologuard has a potential US market of $1.2 billion if the company can penetrate 30 percent of the colorectal cancer screening market, if each test is reimbursed at $300, and if physicians repeat testing every three years.
The American Cancer Society estimates that there will be more than 100,000 new patients with colon cancer and nearly 40,000 new rectal cancer patients in the US this year. Colorectal cancer is the third leading cause of cancer-related deaths, and the ACS projects that nearly 50,000 people will die from the disease in 2011.
This cancer "is often considered the most preventable, yet least prevented cancer," Exact Sciences said in a statement. "Colorectal cancer is highly treatable if found early, but 40 percent of adults age 50 and older have not been screened as recommended."
Exact Sciences is hoping that Cologuard will be a critical addition to physicians' armamentarium of screening tools and improve their ability to detect the presence of colorectal cancer early enough to impact downstream survival.
The company notes on its website that the latest ACS guidelines recommend stool DNA screening as an option for early CRC detection. “There remains a significant unmet medical need to provide additional options for patients at average risk for CRC," Exact Sciences CEO Kevin Conroy said in a statement. "We believe this test could become a great tool for the early detection of this terrible disease and help many of the thousands of patients who are currently not getting screened,"
The Exact CRC screening test gauges two DNA methylation markers and seven DNA mutation markers in cells that are shed from pre-cancerous and cancerous lesions in the lining of the colon into the stool. The test also assesses hemoglobin levels in stool, which is an indicator of whether there is blood in the stool, a potential sign of colorectal cancer.
In order to perform this diagnostic, the patient must collect approximately 8 grams of stool, "about the size of a large grape," and send it to a lab for analysis.
From the sample, DNA targets are isolated, amplified, and analyzed for cancerous and pre-cancerous molecular changes in the colon and rectum. If, according to the lab report, there are such cancerous molecular associations, then the doctor will have to perform a colonoscopy on the patient.
Ahead of FDA approval, however, the CRC screening test is an investigational device and is not available for sale in the US. The firm hopes to introduce Cologuard in the US market in 2013.
GeneNews is also developing a colorectal cancer screening test, called ColoSentry. Last year, the company presented data from a study on the test that suggested that a panel of seven mRNA biomarkers may be able to accurately assess an individual's risk of CRC ahead of colonoscopy (PGx Reporter 09/01/2010). The test is currently sold in Canada and Malaysia. GeneNews has said it plans to begin offering ColoSentry as a laboratory-developed test in certain US markets this year.