A Blood Test That Screens for 50+ Cancers Just Moved Closer to Real-World Use. Here’s What It Means for Grail Investors.

Grail’s Galleri multi-cancer early detection (MCED) test missed its primary endpoint in a 142,000-person NHS trial in England, according to February results. While the trial failed to demonstrate a statistically significant reduction in Stage III-IV cancers, the company is still pursuing FDA approval and medical insurance coverage.

The Galleri test aims to identify more than 50 types of cancer at an early stage. According to Grail, detecting cancers at Stage I or II can improve patient outcomes and lower treatment costs compared to the more invasive treatments required for Stage III and IV cancers.

Following the February announcement, Grail’s stock fell more than 30% in 2026. The price later recovered about 18.4% after a presentation at the American Society of Clinical Oncology (ASCO) annual meeting, though the market reception remained mixed.

Why did the Galleri test miss its primary endpoint?

The trial’s primary goal was to show a “statistically significant Stage III-IV reduction” in the tested group compared to a control group. Grail intended to prove that early detection would naturally lower the number of late-stage diagnoses.

The company did not meet this specific metric in the NHS-Galleri trial. However, management is currently in an iterative process with the FDA to provide further evidence of the test’s suitability for medical coverage.

How does sensitivity vary across different cancer types?

Grail reports a “favorable trend” in detecting a specific group of 12 deadly cancers. These include cancers of the anus, bladder, colorectal, esophagus, head and neck, liver/bile duct, lung, lymphoma, myeloma/plasma cell neoplasm, ovary, pancreas, and stomach.

Data from Grail presentations shows that episode sensitivity—the rate of detection among cancers eventually found—is significantly higher for these 12 cancers than for the overall group.

• NHS-Galleri: 54.7% sensitivity for the 12 deadly cancers vs. 30.7% overall.
• PATHFINDER 2: 69.8% sensitivity for the 12 deadly cancers vs. 39.3% overall.

What role do positive predictive values play in insurance coverage?

Positive predictive value (PPV) measures the percentage of true positives resulting from an initially positive Galleri result. This figure is critical for insurers because false positives lead to expensive, unnecessary diagnostic follow-ups.

According to Grail presentations, the PPV for the NHS-Galleri study was 52%, while the PATHFINDER 2 study showed a PPV of 60.3%. Management argues these results are a strength of the test.

Insurers may not compare these PPVs directly to other tests like Cologuard or mammography. Instead, they’ll likely factor in the relative cost of the Galleri test against the subsequent diagnostic costs.

What is the next step for FDA approval?

Grail’s future depends on FDA decisions and financial analyses by medical insurers. A possible next step involves the release of 12-month follow-up data from the NHS trial.

CFO Aaron Freidin stated at a Goldman Sachs conference that some people in the control arm likely have cancers that haven’t presented clinically yet. He believes these cancers may appear after another 12 months.

If this follow-up data reveals late-stage cancers in the control group, it could support the claim that the Galleri test reduces late-stage detection. This may influence whether the FDA grants approval and whether insurers provide coverage.

Frequently Asked Questions

What is the Galleri test designed to do?

The Galleri MCED test is intended to detect more than 50 types of cancer at an early stage to improve patient outcomes and reduce the costs associated with treating Stage III and IV cancers.

Which studies were used to demonstrate the test’s efficacy?

Grail conducted the PATHFINDER 2 study involving 35,900 people in North America and the NHS-Galleri trial involving 142,000 people in England.

Why is the “12 deadly cancers” group significant?

The test showed much higher episode sensitivity for these 12 specific cancers—up to 69.8% in the PATHFINDER 2 study—compared to the overall sensitivity across all 50+ cancers tested.

Do you believe early detection tests should be prioritized by insurers even if they miss primary trial endpoints?