GRAIL Inc. Achieves Breakthrough in Cancer Detection with PATHFINDER 2 Study

In a monumental stride towards revolutionizing cancer detection, GRAIL, Inc. has announced the positive top-line results from its PATHFINDER 2 registrational study. This study, which commenced in 2021, aimed to evaluate the safety and efficacy of the Galleri® multi-cancer early detection (MCED) test when integrated with standard cancer screening protocols. The results, unveiled on June 18, 2025, have set a new benchmark in the early detection of cancer, showcasing a significant leap from the outcomes of the previously published PATHFINDER study.

Substantial Improvements in Cancer Detection

The PATHFINDER 2 study involved 25,578 participants aged 50 and above, who had no clinical suspicion of cancer. The addition of the Galleri test to standard cancer screening protocols demonstrated a substantial increase in the detection of cancers, far surpassing the results of the initial PATHFINDER study. This advancement not only underscores the potential of the Galleri test in early cancer detection but also highlights its role in potentially saving lives by identifying cancer at stages when it is more treatable and possibly curable.

Maintaining High Specificity and Accuracy

One of the standout features of the PATHFINDER 2 study results is the maintenance of a high specificity rate of 99.5% and an 88% accuracy in determining the cancer’s origin. These figures are crucial in minimizing false positives and ensuring that the test’s findings are reliable and actionable. Furthermore, the study reported no serious safety concerns, reinforcing the Galleri test’s safety profile.

FDA Breakthrough Device Designation

The promising results from the PATHFINDER 2 study have propelled the Galleri test towards FDA approval, with the test receiving a Breakthrough Device Designation. This status is pivotal as it allows for an accelerated review process by the FDA, highlighting the test’s potential to address unmet medical needs in cancer detection. While a complete Premarket Approval (PMA) submission is not expected until the first half of 2026, the breakthrough designation is a significant step forward.

The Path Ahead

Despite the groundbreaking results, detailed study findings have not yet been made publicly available, and additional analyses are required to compare different versions of the Galleri test. However, the substantial improvements in cancer detection rates, coupled with the test’s high specificity and accuracy, mark a significant advancement in the field of oncology.

A New Era in Healthcare

The success of the PATHFINDER 2 study is a testament to the transformative potential of integrating advanced technologies like sequencing, machine learning, and automation in healthcare. As the global healthcare landscape continues to evolve, innovations like the Galleri test are paving the way for a future where early cancer detection is not just a possibility but a reality. With an aging population and the escalating costs of cancer treatment, the need for effective early detection methods has never been more critical. GRAIL, Inc.’s achievements with the Galleri test represent a beacon of hope, promising a future where cancer can be detected and treated at its earliest stages, significantly improving patient outcomes and potentially saving millions of lives worldwide.