GRAIL (GRAL) investor relations material

Study overview and design

• PATHFINDER 2 is the largest U.S. interventional study of a multi-cancer early detection (MCED) test, enrolling over 35,000 adults aged 50+ across multiple centers to assess Galleri's performance and safety in a diverse, intended-use population.

• The study is a prospective, multi-center, interventional trial with a single blood draw and CSO-guided diagnostic workup at physician discretion, with participants followed for up to three years.

• The first 25,000+ participants with at least one-year follow-up formed the registrational dataset for FDA submission.

• PATHFINDER 2 and NHS-Galleri are the two largest MCED studies, totaling nearly 400,000 participants in the clinical program.

• The study included participants in remission or cured of cancer, requiring at least three years post-treatment.

Key efficacy and performance results

• Galleri's positive predictive value (PPV) was 62%, with specificity at 99.6% (0.4% false positive rate) and negative predictive value (NPV) at 99.1%.

• Overall episode sensitivity for all cancers was 40.4%, with higher sensitivity in key subgroups: 73.7% for the 12 deadliest cancers, 55% for cancers without screening options, and 74% for aggressive cancers responsible for two-thirds of cancer deaths.

• Adding Galleri to standard-of-care screening increased cancer detection rate by over 7 times compared to standard screening alone.

• 73–75% of Galleri-detected cancers lacked recommended screening options, and over half (53.5%) were found at early stages (I or II).

• Galleri detected about three times as many cancers when added to standard screening for five major cancers.

Diagnostic and operational outcomes

• Galleri's cancer signal origin (CSO) prediction was accurate in 91.7–92% of true positives, enabling efficient diagnostic workups.

• Median time to diagnostic resolution was 36 days for true positives and 46 days for all MCED-positive participants.

• Only 0.6% of participants underwent an invasive procedure for a positive result, with such procedures twice as common in those diagnosed with cancer.

• No serious study-related adverse events were reported.

• Results require interpretation by healthcare providers and confirmatory diagnostics if positive.