On June 18, 2025 GRAIL, Inc. (Nasdaq: GRAL), a healthcare company whose mission is to detect cancer early when it can be cured, reported positive top-line performance and safety results from the pre-specified analysis of the first 25,578 participants in GRAIL’s registrational PATHFINDER 2 study (Press release, Grail, JUN 18, 2025, View Source [SID1234653986]). PATHFINDER 2 was initiated in 2021 to evaluate the safety and performance of the Galleri multi-cancer early detection (MCED) test when added to standard of care single cancer screening in 35,878 adults over 50 years of age with no clinical suspicion of cancer.
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In the previously published PATHFINDER study, adding Galleri to standard of care cancer screening more than doubled the overall number of cancers detected by screening. In PATHFINDER 2, adding Galleri to standard of care screening demonstrated substantially greater additional cancer detection than in PATHFINDER.
In PATHFINDER, Galleri demonstrated a positive predictive value (PPV), or likelihood that a positive Galleri test was confirmed to be cancer, of 43%; specificity of 99.5%; and 88% cancer signal origin (CSO) accuracy. Data from evaluable PATHFINDER 2 participants with 12 months of follow-up showed a substantially higher PPV than that observed in the PATHFINDER study. CSO accuracy and specificity were consistent with that observed in the PATHFINDER study.
There were no serious safety concerns reported in PATHFINDER 2.
"We are delighted to see very encouraging performance of the Galleri MCED test as a cancer screening tool in broad intended use populations of asymptomatic adults over 50 years of age in both the PATHFINDER 2 study and the NHS-Galleri trial’s prevalent screening round," said Josh Ofman, MD, MSHS, President at GRAIL. "We would like to extend our sincere gratitude to all of the participants and investigators in both of these pivotal studies, who are collectively helping to realize the potential of this groundbreaking technology for population-scale multi-cancer early detection and move the field forward. We look forward to sharing the detailed PATHFINDER 2 data at a medical congress later this year."
PATHFINDER 2 study results will be submitted to the U.S. Food and Drug Administration (FDA) as part of the Galleri premarket approval application (PMA), along with data from the prevalent screening round of the NHS-Galleri trial. In addition, GRAIL will submit to the FDA bridging analyses to compare performance of the version of Galleri used in the PATHFINDER 2 study and the NHS-Galleri trial to the updated version that GRAIL plans to submit to the FDA for premarket approval. The PMA for Galleri is currently in process with a modular submission under a Breakthrough Device Designation from the FDA. GRAIL expects to complete the PMA modular submission in the first half of 2026.
Detailed results from the PATHFINDER 2 study will be submitted for presentation at a leading international oncology meeting before the end of the year.
About the PATHFINDER 2 Study (NCT05155605)
PATHFINDER 2 is a prospective, multi-center, interventional study evaluating the safety and performance of Galleri in approximately 35,000 individuals aged 50 years and older who are eligible for guideline-recommended cancer screening in the United States. The primary objectives of the study are 1) to evaluate the safety and effectiveness of the Galleri MCED test based on the number and type of diagnostic evaluations performed in participants who receive a cancer signal detected test result, and 2) to evaluate the performance of the Galleri MCED test across various measures, including PPV, negative predictive value (NPV), sensitivity, specificity, and CSO prediction accuracy. Participants who receive a cancer signal detected result undergo additional diagnostic testing based on the predicted CSO to determine if a cancer is present. Secondary objectives include utilization of guideline-recommended cancer screening procedures after use of the MCED test, and participant reported outcomes (PRO) over several time points, including an assessment of participants’ anxiety and satisfaction with the MCED test.