Guardant Health's Shield blood test has demonstrated robust performance metrics in detecting colorectal cancer across different disease stages, according to updated clinical data from the expanded ECLIPSE study cohort. The blood-based screening test achieved 84% overall sensitivity for colorectal cancer detection while maintaining 90% specificity for advanced neoplasia, providing further validation of its diagnostic capabilities in average-risk populations.
The updated analysis, derived from the prospective, observational, multicenter ECLIPSE trial conducted across over 130 sites in the United States, evaluated the latest algorithm (V2) for the liquid biopsy test against standard-of-care screening colonoscopy. The study's stage-specific sensitivity data revealed particularly strong performance in detecting later-stage cancers, with 100% sensitivity for stage II and 96% sensitivity for stage III colorectal cancer, while stage I detection reached 62% sensitivity.
Clinical Performance and Validation
The ECLIPSE study enrolled nearly 8,000 participants between ages 45 and 84, with an average age of 60 years and 54% female representation. The cohort's racial and ethnic composition aligned with 2020 U.S. Census demographics, including 78.5% white, 12% Black, and 7% Asian participants, with 13% identifying as Hispanic or Latino.
Among 65 participants with colonoscopy-detected colorectal cancer, the Shield test identified 54 cases, translating to approximately 83% accuracy in the original analysis. The test demonstrated superior performance in detecting colorectal cancers compared to advanced precancerous lesions, identifying advanced adenomas with only 13% sensitivity.
"We are pleased with the performance of the new algorithm in detecting stage I CRCs. Today's update shows yet again that Shield delivers best-in-class performance," said AmirAli Talasaz, Guardant Health co-CEO. "We will continue to leverage our first-mover advantage, rapidly growing database, and innovation engine to push Shield to higher levels of performance over time."
Regulatory Approval and Clinical Guidelines
The FDA approved the Shield test in March 2024, following a favorable advisory panel vote in May 2024. The panel supported the test's safety by an 8-1 vote, effectiveness by 6-3, and benefit-risk profile by 7-2. This approval was supported by data from ECLIPSE published in The New England Journal of Medicine.
The National Comprehensive Cancer Network (NCCN) recently updated its colorectal cancer screening guidelines to include the Shield test as the first blood-based test recommended for primary screening. This guideline inclusion represents a pivotal development expected to facilitate greater patient access and improve screening rates.
Addressing Screening Gaps
Colorectal cancer represents the third most common cancer and second leading cause of cancer-related death, yet only approximately 60% of eligible individuals undergo appropriate screening. The Shield test aims to address this screening gap by offering a noninvasive alternative that requires less preparation than traditional methods.
"Having a blood-based screening test available will lead to more patients agreeing to undergo screening and hopefully improve screening rates, as they see it as less invasive," noted Sean Langenfeld, MD, a colorectal surgeon at Nebraska Medicine who was not involved in the study.
The test's accuracy rate of 83% compares favorably to the fecal immunochemical test (FIT) at 79% accuracy, though it falls below the 92% accuracy rate of Cologuard fecal DNA testing. However, the blood test offers advantages in convenience and patient acceptance.
Clinical Implementation and Limitations
The Shield test is available by prescription only and costs $895 when paid out-of-pocket. Since its launch in May 2022, more than 20,000 people have used the test. The recommended screening interval is every three years, with positive results requiring follow-up colonoscopy for definitive diagnosis.
FDA advisory committee members noted specific limitations of the test. "It's a good colon cancer screening test, but for later-stage colon cancer," said Karla Ballman, PhD, of the Mayo Clinic College of Medicine and Science. "It's not as good in stage 1, and definitely not good for advanced adenoma [precancerous lesions]."
The test is most appropriate for average-risk patients who are unable or unwilling to undergo colonoscopy, according to clinical experts. Participants in the ECLIPSE study had no family history of colorectal cancer, no personal history of cancer, and no diagnosis of inflammatory bowel disease or large polyps.
Future Applications
Beyond colorectal cancer screening, Guardant Health is leveraging the Shield platform for broader applications, including a multicancer detection test that has received FDA Breakthrough Device Designation and inclusion in the National Cancer Institute's Vanguard study. This suggests expanding use of cell-free DNA technology across multiple oncology applications, from early detection to treatment selection and recurrence monitoring.
