FDA Staff Flag No Major Concerns on Grail's Galleri Cancer Test, Shares Jump 35% Ahead of Wednesday Vote

Grail Inc. (NASDAQ: GRAL) shares surged 35% on Monday, September 21, after the FDA released briefing documents ahead of Wednesday's advisory panel meeting on the company's Galleri blood test, according to Reuters reporting carried by WSAU. Piper Sandler analyst David Westenberg called the review "constructive for Grail" and said he expects a favorable vote, per the same Reuters report.

The FDA's Molecular and Clinical Genetics Panel meets Wednesday, September 23, at the agency's White Oak campus in Silver Spring, Maryland, to review Grail's premarket approval application for Galleri, according to aidiagme. This is the first time a U.S. expert panel has formally reviewed a multi-cancer detection blood test through the premarket approval process. The public docket for the meeting, numbered FDA-2026-N-8004, closed September 16.

According to MedPage Today, FDA staff members said they had no outstanding questions on Galleri's analytical performance, study design, or primary safety analyses. Staff wrote that blood-based multicancer tests "may provide detection of cancers that would otherwise go undetected," since most U.S. cancer deaths come from cancer types with no guideline-recommended screening program.

The numbers from the two studies underpinning Grail's application show solid test performance. In PATHFINDER 2, a U.S. study of 25,490 participants, Galleri showed 12-month sensitivity of 35.0%, specificity of 99.85%, a positive predictive value of 77.0%, and cancer-signal-origin prediction accuracy of 94.3%, per MedPage Today. In the NHS-Galleri trial, a randomized UK study of more than 70,000 participants in its intervention arm, the test showed sensitivity of 31.6%, specificity of 99.74%, positive predictive value of 66.2%, and origin-prediction accuracy of 91.9%.

Despite the clean bill on safety and accuracy, the FDA is asking its advisers to discuss something more fundamental: whether the evidence actually supports calling Galleri an "early detection" test, according to Reuters and Traders Union. That question exists because the NHS-Galleri trial, presented at the American Society of Clinical Oncology meeting in May, failed to meet its primary goal of reducing the number of cancers diagnosed at stage III or IV across a dozen tumor types with no existing screening option, per MedPage Today. The FDA's briefing document did not review that specific endpoint, focusing instead on test performance and safety.

That failed endpoint is the strongest concern critics have raised, and it's a fair one. A test marketed for early detection missed its own trial's main measure of whether it actually shifts cancers to earlier, more survivable stages.

Grail and its supporters push back on that framing. A Hindustan Times editorial argues the topline miss obscures a more favorable pattern in the underlying data: stage IV diagnoses in the trial's intervention arm fell 14% compared to the control group, while stage III diagnoses rose 25%, and the piece contends that shift toward earlier staging grew larger the longer the trial ran. It also notes Galleri caught four times as many cancers overall as the UK's four recommended screening programs combined, and increased detection of the 12 deadliest cancers at stages I and II by 16%. That piece reads as opinion advocacy for approval rather than straight reporting, and it should be read that way. It's making Grail's best case, not adjudicating the trial's primary result.

A panel recommendation is advisory, not binding, aidiagme and MarketBeat both note. The FDA usually follows its advisory committees but isn't required to, and a final approval decision could take weeks or months after Wednesday's vote. Until then, Galleri and Abbott Laboratories' competing Cancerguard test remain on the market as laboratory-developed tests under Clinical Laboratory Improvement Amendments rules, a category that does not require proof of clinical benefit to patients, according to Reuters and aidiagme. The National Cancer Institute still states plainly that no multicancer detection test has been authorized by the FDA.

Grail generated $136.8 million in U.S. revenue from Galleri in 2025, per Reuters. Full FDA approval would open the door to routine insurance coverage and physician guideline adoption, which the company has been unable to secure while operating under the lab-developed-test pathway. Grail's stock had fallen more than 20% since February, when the company first disclosed the UK trial's missed endpoint, before Monday's 35% jump. The panel votes Wednesday, September 23, at the FDA's public meeting, running 9 a.m. to 6 p.m. Eastern; the agency's own decision date has not been announced.