Food and Drug Administration reviewers have no outstanding questions for an advisory panel about the primary safety analysis or laboratory performance of GRAIL's Galleri multi-cancer blood test, according to an FDA executive summary posted ahead of Wednesday's meeting. The same document shows the test flagged only about one in three cancers diagnosed within a year of a blood draw, and far fewer of the earliest-stage tumors.
That second finding matters most for adults 50 and older who already buy the test by prescription. An earlier version has been available in the United States since 2021. A "No Cancer Signal Detected" result can feel like a clean bill of health, but the agency's numbers show most cancers found during follow-up were not flagged in advance.
Galleri is not FDA-approved. The panel's votes on Sept. 23 are advice to the agency, not an approval, and national screening guidelines for breast, colorectal, cervical, lung, and prostate cancer have not changed. The performance figures reflect 12 months of follow-up, with PATHFINDER 2 data running through Dec. 31, 2024.
Stage-by-Stage Numbers Behind the Safety Verdict
MedicalDaily previously reported that the panel would weigh a randomized trial that missed its main goal before the agency's own analysis was public. That analysis is now out, and it shifts the question from whether Galleri finds cancer to which cancers it finds.
In the U.S. PATHFINDER 2 study, Galleri detected 35.0% of cancers diagnosed within 12 months. Specificity was 99.85%, and 77.0% of positive results were confirmed as cancer. In the first screening round of England's NHS-Galleri trial, the test detected 31.6% of cancers, with 99.74% specificity, and 66.2% of positive results were confirmed as cancer. False alarms were rare: fewer than 3 in every 1,000 people without cancer received a positive result.
Detection climbed with stage. Galleri caught 21.4% of stage I cancers in PATHFINDER 2 and 13.6% in NHS-Galleri, compared with 63.2% and 60.0% of stage IV cancers. FDA reviewers cautioned that the stage figures may carry bias, because a missed cancer is staged later, when it surfaces on its own.
Results also varied by cancer type. The test found about 80% of liver and intrahepatic bile duct cancers in both studies, but only 10.7% of prostate cancers and 19% to 26% of breast cancers.
These estimates differ from earlier published trial results for a specific reason. Trial participants received results from an earlier version of the test, called MCED-V2, while the FDA analyzed the current Galleri version by retesting stored blood samples.
Safety data come from that earlier version. Among 90 PATHFINDER 2 participants with a positive result but no cancer diagnosed within a year, 43 underwent at least one invasive procedure, most often an endoscopy. Participants with false-positive results took a median of 75 days to reach a diagnostic resolution. No adverse events were attributed to the device in PATHFINDER 2, and neither study reported a serious adverse event related to study procedures or the test.
A Clean Result Carries the Biggest Household Risk
For families, the risk runs in two directions. A false alarm can mean weeks of scans, specialist visits, and worry. False reassurance can be more dangerous.
The FDA summary warns that people wrongly identified as cancer-free "may be at risk for delayed cancer detection,"especially if they skip standard screening for the convenience of a blood draw. The agency also cited American Cancer Society estimates that only about 65% of eligible adults are up to date on colorectal cancer screening and about 14% of eligible current and former smokers are up to date on lung cancer screening.
That gap is where a household decision can go wrong. A 58-year-old who is overdue for a colonoscopy might treat a negative Galleri report as permission to wait. The data do not support that choice, and GRAIL's proposed labeling says the test is not a replacement for recommended single-cancer screening tests. GRAIL has also said publicly that the test is meant to be used in addition to recommended screenings, not in place of them.
People with symptoms such as unexplained weight loss, rectal bleeding, a new lump, or persistent pain fall outside the intended use and need a diagnostic evaluation, not a screening test. Adults weighing Galleri can reasonably ask a clinician what follow-up a positive result would trigger, what their insurer would pay for that follow-up, and which standard screenings they are due for now. An FDA approval would not, by itself, settle insurance coverage.
Wednesday's Three Votes and the Open Questions
The Molecular and Clinical Genetics Panel of the Medical Devices Advisory Committee meets from 9 a.m. to 6 p.m. Eastern, according to the agency's meeting page. Members will vote on whether there is reasonable assurance that Galleri is safe, whether it is effective, and whether its benefits outweigh its risks for adults 50 and older.
The sharpest dispute centers on one word. Reviewers asked the panel whether the stage-by-stage results justify calling Galleri an "early" detection test. If they do not, the panel may consider a narrower claim describing cancer detection without that word.
Other gaps remain. No trial has shown that Galleri screening lowers cancer deaths. In NHS-Galleri's first round, stage IV diagnoses among 12 prespecified cancer types were 13% lower in the screened group, but no formal statistical testing was done, and the difference could reflect chance. The panel will also discuss whether post-approval studies should be required.
The FDA is not bound by the votes and has not announced a decision date. MedicalDaily will report the outcome as the panel votes.
Galleri Review Timeline
Sept. 23, 2026: The FDA's Molecular and Clinical Genetics Panel meets to discuss and vote on Galleri.
Aug. 10, 2026: The FDA formally announces the panel meeting and opens a public comment docket in a Federal Register notice.
Aug. 7, 2026: GRAIL announces that an FDA advisory panel will review its application.
Jan. 29, 2026: GRAIL submits its premarket approval application for Galleri.
Key Questions Answered
Did FDA reviewers find safety problems with Galleri?
Not major ones. The FDA summary says reviewers have no outstanding questions for the panel on the primary safety analysis or on the test's laboratory performance.
How many cancers did Galleri detect in the FDA's analysis?
About one in three cancers diagnosed within 12 months: 35.0% in PATHFINDER 2 and 31.6% in the first round of NHS-Galleri.
Does the test find early cancers?
Less often. It detected 21.4% and 13.6% of stage I cancers in the two studies, compared with about 60% of stage IV cancers.
How often is a positive result correct?
In the FDA's analysis, 77.0% of positive results in PATHFINDER 2 and 66.2% in NHS-Galleri were confirmed as cancer.
Is Galleri approved?
No. Wednesday's panel votes are advisory, and the FDA makes the final decision on its own timeline.
Can a negative result replace a colonoscopy or mammogram?
No. GRAIL's proposed labeling says the test is not a replacement for recommended single-cancer screenings.
Who should talk to a clinician now?
Adults 50 and older who are considering the test, and anyone with symptoms such as unexplained weight loss, bleeding, or a new lump, who needs a diagnostic evaluation rather than screening.
