GRAIL, Inc. has announced topline results from the NHS-Galleri trial, a large-scale, randomised controlled study evaluating annual multi-cancer screening using the Galleri test within National Health Service (NHS) England.

The three-year study enrolled approximately 142,000 demographically representative participants aged 50 to 77 to assess whether adding the Galleri blood test to standard-of-care screening could reduce late-stage cancer diagnoses and improve overall cancer detection rates at a population level.

While the trial did not meet its primary endpoint of achieving a statistically significant reduction in combined Stage III–IV cancer diagnoses, it demonstrated a favorable trend toward fewer late-stage cancers in a pre-specified group of 12 high-mortality cancer types after the initial screening round.

Notably, adding Galleri to standard screening resulted in a substantial and clinically meaningful reduction in Stage IV diagnoses across the 12 pre-specified deadly cancers. Stage IV cases declined progressively with each annual screening round, with more than a 20 percent reduction observed in the second and third rounds. Similar reductions were seen across all cancers studied.

The trial also showed that annual Galleri screening, combined with existing NHS screening programmes for breast, colorectal, cervical and high-risk lung cancers, delivered a four-fold improvement in overall cancer detection rates compared to standard-of-care screening alone. There was a marked increase in the number of Stage I–II cancers detected in the intervention arm, particularly among cancer types that are typically diagnosed at later stages.

Bob Ragusa, Chief Executive Officer of GRAIL, described the findings as the strongest evidence to date that multi-cancer early detection can shift the stage of diagnosis at a population level. He highlighted the significant reduction in Stage IV diagnoses and the consistent performance of the test across key metrics, including positive predictive value, specificity and cancer signal-of-origin accuracy.

Screening with Galleri also led to a substantial reduction in cancers detected via emergency presentation, which are often associated with higher mortality rates and increased healthcare costs.

Professor Charles Swanton, a thoracic medical oncologist at University College Hospital London and one of the trial’s chief investigators, noted the clinical importance of earlier-stage detection. He emphasised that identifying cancer before distant metastasis significantly increases the likelihood of curative treatment, whereas metastatic disease often limits therapy to long-term management rather than cure.

No serious safety concerns were reported among participants who received the Galleri test. Additional analyses are ongoing, and detailed findings are expected to be presented at the ASCO 2026 Annual Meeting. GRAIL also plans to extend follow-up by six to twelve months to further evaluate long-term impact as the data mature.

The Galleri test is currently under premarket approval review by the US Food and Drug Administration, with the NHS-Galleri trial data forming part of the submission.