A large North American clinical trial published in Nature Medicine reveals that combining GRAIL’s Galleri multi-cancer early detection blood test with routine screenings increased cancer detection 6.5-fold. The findings arrive as federal regulators review evidence for potential approval, showing the test’s high specificity and ability to catch asymptomatic tumors.
PATHFINDER 2 Results Show High Detection Rates
Oregon Health & Science University served as the study’s largest and leading enrollment site, contributing approximately 6,100 participants through the Knight Early Detection Clinical Research team. Across 32 clinical sites located in the United States and Canada, the PATHFINDER 2 study recruited 35,878 adults aged 50 and older, establishing it as the biggest interventional study for multi-cancer early detection carried out in North America. Participants provided a blood sample to test cfDNA extracted from plasma using GRAIL’s Galleri test.
Among the cancers newly identified by the test, nearly half were diagnosed at stages 1 through 2, and nearly three-quarters were caught at stages 1 through 3. When added to clinical screening recommendations for breast, colorectal, cervical, and lung cancers, the blood test increased the number of cancers detected through screening 6.5-fold.
Blood Test Finds Cancers Lacking Standard Screening
In the PATHFINDER 2 study, 70% of the cancers newly detected by the blood test were malignancies that currently have no national screening recommendations.
Out of 287 participants who received a positive cancer signal, 173 were ultimately diagnosed with cancer. A machine-learning algorithm is employed by the technology to analyze chemical signatures that differentiate cell-free DNA shed by healthy tissue from that released by tumors. This yielded a positive predictive value of 60.3% alongside a specificity of 99.64%, which translates to a false-positive rate of 0.36%.
Trial Data Reaches FDA For Regulatory Review
The publication of the study in Nature Medicine coincides with a regulatory review.
The finding led to a diagnosis of cancer that was caught when still localized. Physicians involved in the trial point to individual cases to illustrate the clinical utility of finding tumors before symptoms emerge.
Investigators emphasize that the blood test is not intended to replace routine screenings, but rather to function as a complement that catches more cancers early. Now 88, he remains cancer-free.