23 Sept 2026

NHS-Galleri trial misses main endpoint for multi-cancer blood test

Medical technology and bioelectronics
AI illustration · Illustrative scene, not a photograph of the specific device or experiment.

What was demonstrated

In the NHS-Galleri randomised trial in England, 142,250 adults aged 50 to 77 were randomised 1:1 to a test group (71,122) or a control group (71,128). The test group was offered the Galleri multi-cancer blood test. After three screening rounds, the combined rate of stage III or IV diagnoses across 12 prespecified cancers was not lower in the test group (incidence rate ratio 1.03, 95% CI 0.92 to 1.14, P=0.63). Stage IV diagnoses, a prespecified secondary endpoint, were lower in the test group (incidence rate ratio 0.86, 95% CI 0.744 to 0.998), which GRAIL describes as nominally statistically significant. Episode sensitivity was 54.7% for the 12 prespecified cancers and 30.7% across all cancer types, with specificity of 99.55% and a positive predictive value of 52.0%.

Why it matters

The trial tested whether adding a multi-cancer blood test to standard screening lowers late-stage cancer in a national health system. It did not meet its main goal, and a lower stage IV count does not yet show fewer deaths.

Caveats

  • The primary endpoint was not met. The stage IV result is a secondary endpoint, and its confidence interval only just excludes 1.00.
  • Follow-up was 12 months after the first two screening rounds and a median of 17 months after the third. The sources checked do not report cancer deaths, so the trial does not show whether earlier detection saves lives.
  • Episode sensitivity across all cancer types was 30.7%, so most cancers diagnosed within 12 months of a blood draw were not flagged by the test.
  • The figures here come from GRAIL's May 2026 conference release and from an ASCO Post report of the New England Journal of Medicine paper (Sasieni et al.). The NHS-Galleri trial site also says a second paper, in Nature Medicine, covers test accuracy. Neither paper was opened, so both should be checked before approval.

Technology profiles

Sources

  1. other
    First full results from the NHS-Galleri trial published in leading journals
    NHS-Galleri trial website (GRAIL Bio UK Ltd), 23 Sept 2026.
  2. company announcement
    GRAIL Reports Full Results From NHS-Galleri Trial Demonstrating Substantial Reduction in Stage IV Cancer Diagnoses at 2026 ASCO Annual Meeting
    GRAIL, 30 May 2026.
  3. news
    Multicancer Early Detection Screening Does Not Reduce Overall Late-Stage Cancer Diagnosis
    Wendy LaGrego. The ASCO Post, 1 Oct 2026.

Last reviewed 21 Oct 2026.