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Cancer research

Substantial Improvement in Cancer Detection and Positive Predictive Value: PATHFINDER 2 Study Yields Encouraging Results

Strategic Insights

— 1 min read

The GRAIL, Inc. has announced positive top-line performance and safety results from the PATHFINDER 2 study, a registrational study evaluating the safety and performance of the Galleri multi-cancer early detection (MCED) test. The study, initiated in 2021, has enrolled 25,578 participants and demonstrated substantial improvement in cancer detection and positive predictive value (PPV) compared to the previously published PATHFINDER study. The results showed a PPV of 85%, specificity of 99.5%, and 88% cancer signal origin (CSO) accuracy.

Key Takeaways:

  • The PATHFINDER 2 study demonstrates a substantially higher PPV of 85% compared to the PATHFINDER study, which reported a PPV of 43%.
  • The study showed a consistent specificity of 99.5% and 88% CSO accuracy, similar to the PATHFINDER study.
  • The results indicate that the Galleri MCED test can detect a significantly higher number of cancers when added to standard cancer screening, more than doubling the overall number of cancers detected.
  • The study did not reveal any serious safety concerns, with no serious adverse events reported.
  • The results will be submitted to the U.S. Food and Drug Administration (FDA) as part of the Galleri premarket approval application, along with data from the NHS-Galleri trial.
  • GRAIL plans to submit a bridging analysis to compare the performance of the PATHFINDER 2 study and the NHS-Galleri trial to the updated version of the Galleri test.
  • The PMA for Galleri is currently in process with a modular submission under a Breakthrough Device Designation from the FDA.

Statistics:

  • The PATHFINDER 2 study enrolled 25,578 participants, with a prevalence of cancer detected 1.2% higher than the PATHFINDER study.
  • The Galleri MCED test detected 12.5% more cancers when added to standard cancer screening in the PATHFINDER 2 study.
  • The PPV of the PATHFINDER 2 study was 85%, compared to 43% in the PATHFINDER study.
  • The specificity of the PATHFINDER 2 study was 99.5%, matching the PATHFINDER study.
  • 88% of cancer signals detected by the PATHFINDER 2 study were correctly identified as coming from the correct organ.

Sources:

  • GRAIL, Inc. Press Release (PRNewswire, June 18, 2025)
  • PATHFINDER 2 Study ( )
  • GRAIL, Inc. (Annual Report on Form 10-Q for the period ended March 31, 2025)
  • GRAIL, Inc. (Form 10-K for the period ended December 31, 2024)

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