Guardant Health’s Shield blood test for colorectal cancer (CRC) screening was strongly recommended by the Molecular and Clinical Genetics Panel of the U.S. FDA’s Medical Devices Advisory Committee, in adults age 45 and older who are at average risk for the disease. The Committee voted 7-to-2 that its benefits outweigh its risks, 8-to-1 that Shield is safe, and 6-to-3 that it is effective.
Shield will be a key entrant in the growing cancer blood testing market, which is estimated to be worth more than $16B by 2030. A recent abstract at ASCO’s 2024 meeting reported that screening for colorectal cancer represented approximately two-thirds of the total cost of cancer screening in the U.S.
“The advisory committee’s strong support for the approval of Shield reinforces the crucial role that a blood test option can have in improving CRC screening rates for those at average risk,” said AmirAli Talasaz, co-CEO of Guardant Health.
The recommendation was partly based upon data from the ECLIPSE study, which was published in NEJM, in March 2024. One of the largest studies of its kind, ECLIPSE (Evaluation of ctDNA LUNAR Assay In an Average Patient Screening Episode) is a 20,000 plus patient registrational study to evaluate the performance of Shield compared to a screening colonoscopy. The Shield test detects colorectal cancer signals in the bloodstream from DNA that is shed by tumors, called circulating tumor DNA (ctDNA).
The test showed a 83.1% CRC detection rate and 89.6% specificity rate—meaning those patients had a negative Shield result and no advanced colorectal neoplasia detected by colonoscopy. But sensitivity for advanced precancerous lesions was just 13.2%.
The FDA is expected to decide whether to approve Shield later this year. If approved, it could become the second blood-based test for CRC diagnosis in the United States, after Epigenomics’ Epi proColon, which was approved by FDA in 2016 and uses a real-time PCR assay to detect methylated Sept9 DNA (a biomarker for CRC) in plasma derived from a whole blood sample.
“Despite the importance of detecting colorectal cancer early, there are notable barriers that can deter average-risk Americans from completing existing screening methods. Shield effectively detects cancer at an early stage when it is most treatable. Providing people with this blood test alongside other non-invasive stool tests can increase the rate of colorectal screening and potentially reduce preventable CRC deaths,” said Talasaz.
Colorectal cancer is the second-leading cause of cancer-related deaths in the U.S. yet has a 91% five-year survival rate when caught at stage I (localized). Despite this, one out of three eligible Americans—50 million people—are not being screened for CRC. Current primary non-invasive screening options include stool-based tests which have proven efficacy in detecting CRC, however, studies have consistently found that barriers such as handling stool and challenges performing the test impact adherence that can be completed with a simple blood draw during a routine office visit.
“Sadly, 76% of deaths caused by colorectal cancer occur in individuals who are not up to date with their screening, said Daniel Chung, MD, gastroenterologist at Massachusetts General Hospital and professor of medicine at Harvard Medical School. “Clinical evidence and CRC screening guidelines acknowledge the value of offering choice to individuals at average risk for CRC and highlight the role of patient preference in test selection and CRC screening completion.”
The results of ECLIPSE showed that Shield’s performance is within range of existing stool-based tests used as primary CRC screening options, in which overall sensitivity ranges from 67 to 92%.
