A large, three-year clinical trial designed to demonstrate how Grail’s blood test for early cancer detection could work in a broad population has preliminary results showing reduction in cancer diagnoses, but not enough to be statistically significant.
The outcome means this test, named Galleri, failed to meet the main goal of the study. Grail did not disclose specific figures in its announcement of the preliminary data after Thursday’s market close, but the company pointed to a “favorable trend.” Fewer late-stage cancer diagnoses were observed in a prespecified group in the intervention arm. Grail said these results suggest the potential for a stronger effect with longer follow-up time.
Grail plans to extend the trial’s follow-up period by six to 12 months. Clinicians and investors will get a closer look at the trial sooner. Analysis of the data to date are ongoing and Grail said detailed results will be submitted for presentation at the annual meeting of the American Society of Clinical Oncology in late May. But in the meantime, investors have soured on the company’s stock. Shares of Grail, which went public after spinning off of Illumina in 2024, opened Friday at $48.88 apiece, down more than 51% from Thursday’s closing price.
Galleri is a so-called liquid biopsy. From a small sample of blood, this Grail test detects DNA fragments that tumors shed into the bloodstream. These signs may be detected even before symptoms show. The idea is to detect cancer early, when intervention offers a greater chance of treatment success. Galleri was developed to detect cancer signals shared by more than 50 types of cancer. Previous clinical studies provided validation for the test.
The results announced Thursday are from a study conducted in the United Kingdom that enrolled more than 140,000 asymptomatic people age 50 to 77. Participants were randomly assigned to an intervention arm or a control arm and blood samples from all were collected over two years. The main goal was to measure the absolute number of stage III and stage IV cancers diagnosed after three to four years, potentially showing a reduction in these late-stage cancers in those who received the Galleri test compared with those who did not.
The U.K. study added Galleri to standard-of-care screening. Grail reported the combination of these tests led to a four-fold improvement in the overall cancer detection rate compared to standard-of-care screening alone for breast, colorectal, cervical, and high-risk lung cancer. In the intervention arm, the company also pointed to a “substantial increase” in the absolute number of stage I and stage II cancers in the 12 pre-specified deadly cancer types (cancers of the anus, bladder, colorectal, esophagus, head and neck, liver/bile duct, lung, lymphoma, myeloma/plasma cell neoplasm, ovary, pancreas, stomach) that are typically found in late stages.
Though the results fell short of statistical significance, Harpal Kumar, president biopharma & Europe, Grail, said during a Thursday evening conference call that stage IV diagnoses in these cancers decreased with each year of sequential screening with a greater than 20% reduction in the second and third rounds of screening. Similar reductions were observed across all cancers. He added that screening with Galleri resulted in a substantial reduction in the number of cancers detected clinically from an emergency or unplanned hospital visit.
“The reduction in stage IV cancer diagnoses is a critically important outcome which we believe can lead to more effective intervention for patients, particularly given the substantial and growing arsenal of effective treatments for many stage III cancers,” Kumar said. “In fact, there is a dramatic improvement in survival for many types of cancer at stage III as compared with stage IV. These results are the first time a multi-cancer early detection test has demonstrated population-scale stage shift and reduction in metastatic disease in a randomized trial.”
Grail launched Galleri in the U.S. in 2021 as a laboratory developed test, a pathway that does not require FDA clearance or approval. Earlier this month, Hims & Hers launched access to Galleri through its platform. Patients still need a prescription, but Hims & Hers will broaden access to the Grail product by adding another digital health and wellness platform offering the test.
Securing FDA approval is seen as key for expanding market adoption and payer reimbursement for Galleri. Late last month, Grail filed the final portion of its application seeking FDA premarket approval for the test. The submission is based on results from a U.S. trial that enrolled 25,490 participants as well as one-year results from the U.K. study. Grail and other liquid biopsy companies have overcome one key reimbursement hurdle. Last month, President Trump signed into law a bill that authorizes Medicare to cover multi-cancer early detection tests that have been approved by the FDA. This coverage will start in 2028.
The Galleri trial readout came alongside Grail’s report of 2025 financial results for the fourth quarter and full year. The company reported $136.8 million in Galleri revenue for 2025, a 26% increase compared to the prior year. For 2025, Grail said it sold more than 185,000 Galleri tests. Since the product’s launch, the company said it has sold nearly half a million tests.
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