GRAIL to Present New Galleri® Data From More Than 32,000 Participants Across the PATHFINDER 2, SYMPLIFY and REFLECTION Studies at ESMO Congress 2025 and EDCC

First PATHFINDER 2 Results Accepted as a Late-Breaking Presentation at the European Society for Medical Oncology (ESMO) Congress 2025; Results to be Submitted to FDA as Part of the Galleri Premarket Approval Application (PMA)

Updated SYMPLIFY and REFLECTION StudyResults to be Presented at the Early Detection of Cancer Conference (EDCC) Highlight Galleri Performance in Symptomatic and Veteran Populations, Respectively

MENLO PARK, Calif.,Sept. 23, 2025/PRNewswire/ -- GRAIL, Inc. (Nasdaq:GRAL), a healthcare company whose mission is to detect cancer early when it can be cured, will present new data highlighting the Galleri®multi-cancer early detection (MCED) test performance and safety from its registrational PATHFINDER 2 study at the European Society for Medical Oncology (ESMO) Congress 2025 in Berlin, Oct. 17-21, 2025. The PATHFINDER 2 study, conducted under an FDA-approved investigational device exemption application, is the largest MCED interventional study conducted in the U.S. in an intended use population with no clinical suspicion of cancer.

As previously reported, top-line results from evaluable PATHFINDER 2 study participants with 12 months of follow-up showed that adding the Galleri test to standard of care screening demonstrated substantially greater additional cancer detection, as well as a substantially higher positive predictive value (PPV),  than observed in the firstPATHFINDER study. Cancer signal of origin (CSO) accuracy and specificity were consistent with the PATHFINDER study.

In addition, the company will present new Galleri data from the follow-up of symptomatic participants enrolled in SYMPLIFY, a prospective observational study, and real world experience of veterans tested with Galleri from the REFLECTION study at the Early Detection of Cancer Conference (EDCC) 2025 inPortland, Ore.,Oct. 21-23, 2025.

"Galleri is the only available MCED test with demonstrated performance in an intended use population being screened for cancer. These new data build on the results from our first clinical implementation study, PATHFINDER, which was published in theLancetin 2023, and showed that Galleri approximately doubled the number of cancers identified when added to standard of care screening," said Josh Ofman, MD, MSHS, President of GRAIL. "We're witnessing the beginning of a transformative era for cancer screening, with these results demonstrating Galleri's ability to detect cancers earlier, when they can be easier to treat and are potentially curable."

More information about timing of the EDCC presentations can be foundhere.

For more information, visitgrail.com.

For more information, visitgalleri.com.

* The Galleri test performance metrics were derived from the outcomes of an interventional clinical study of patients presenting for screening without clinical suspicion of cancer, a study population that reflects the intended use population.

** Test performance metrics do not represent results of a head-to-head comparative study. Separate studies have different designs, objectives, and participant populations, which limits the ability to draw conclusions about comparative performance.

Results should be interpreted by a healthcare provider in the context of medical history, clinical signs, and symptoms. A test result of No Cancer Signal Detected does not rule out cancer. A test result of Cancer Signal Detected requires confirmatory diagnostic evaluation by medically established procedures (e.g., imaging) to confirm cancer.

These statements are only predictions based on our current expectations and projections about future events and trends. There are important factors that could cause our actual results, level of activity, performance, or achievements to differ materially and adversely from those expressed or implied by the forward-looking statements, including those factors and numerous associated risks discussed under the section entitled "Risk Factors" in our Annual Report on Form 10-Q for the period endedJune 30, 2025and our Form 10-K for the period endedDecember 31, 2024. Moreover, we operate in a dynamic and rapidly changing environment. New risks emerge from time to time. It is not possible for our management to predict all risks, nor can we assess the impact of all factors on our business or the extent to which any factor, or combination of factors, may cause actual results, level of activity, performance, or achievements to differ materially and adversely from those contained in any forward-looking statements we may make.

Forward-looking statements relate to the future and, accordingly, are subject to inherent uncertainties, risks, and changes in circumstances that are difficult to predict and many of which are outside of our control. Although we believe the expectations and projections expressed or implied by the forward-looking statements are reasonable, we cannot guarantee future results, level of activity, performance, or achievements. Our actual results and financial condition may differ materially from those indicated in the forward-looking statements. Except to the extent required by law, we undertake no obligation to update any of these forward-looking statements after the date of this press release to conform our prior statements to actual results or revised expectations or to reflect new information or the occurrence of unanticipated events.