SOLAR: A post-approval study evaluating longitudinal performance of a blood-based test for screening individuals at average risk for colorectal cancer (CRC).

Abstract

TPS10632 Background: CRC is a leading cause of cancer-related mortality; CRC screening has been shown to reduce mortality through detection of early-stage disease, yet adherence to recommended screening remains suboptimal. Shield is a methylation partitioning cell-free DNA (mp-cfDNA) blood-based test indicated for CRC screening in average-risk adults age 45 years or older. This test achieved 83% sensitivity for CRC and 90% specificity for advanced neoplasia in a prospective, observational study that enrolled over 20,000 patients (ECLIPSE), and became the first blood-based screening test approved by the FDA as a primary CRC screening option in July 2024. SOLAR is an FDA-mandated, post-approval study to evaluate longitudinal performance of the blood-based mp-cfDNA test in the intended use population. Methods: SOLAR (NCT06880055) is an observational, prospective study supplemented with real-world data to evaluate the mp-cfDNA test following a second round of CRC screening. Patients will receive an initial mp-cfDNA test (Shield, Guardant Health, Palo Alto, CA) at baseline (T0). Deidentified healthcare claims data will be collected to assess overall health and any development of disease at 1 and 2 years following the baseline test (T1 and T2, respectively). Patients with a negative screening result at T0 will receive a screening colonoscopy alongside a blood draw approximately 3 years after baseline screening (T3). Patients with a positive result at T0 will be recommended to receive diagnostic colonoscopy. Individuals aged 45-81 years at average-risk for CRC are eligible for the trial. Individuals who have a personal/family history of CRC or are at high risk for CRC are excluded. Those with a positive result from any of the following CRC screening tests are also excluded: fecal occult blood test or fecal immunochemical test within the last 12 months, multi-target stool DNA test within the last 36 months, mp-cfDNA test within the last 36 months, or another CRC screening method within the last six months. Primary outcome is the performance of the mp-cfDNA test at T3, including sensitivity for CRC or advanced adenoma detection and specificity for advanced neoplasia detection. Enrollment began July 2025. There are currently 29 active study sites across the US. Clinical trial information: NCT06880055 .