Signal Galleri Blood Test Fails to Reduce Late-Stage Cancers in Major NHS Trial

Summary

The NHS-Galleri trial enrolled 142,942 participants aged 50 to 77 with no cancer symptoms, each receiving an annual blood draw for three years while also receiving standard recommended cancer screening. The primary endpoint, a combined measure of stage 3 and stage 4 diagnoses across a pre-specified group of 12 cancers comparing the Galleri test plus standard care versus standard care alone, was not met with statistical significance. Grail, the test's maker, highlighted a favorable trend toward fewer stage III-IV cancers in the pre-specified 12-cancer group after the first screening round, and reported that stage IV diagnoses in that group decreased with each year of sequential screening, with more than a 20% reduction in the second and third rounds. ASCO's chief medical officer Dr. Julie Gralow said the results show encouraging trends toward tumor downstaging but stressed the trial did not statistically reduce late-stage cancers against its predefined primary endpoint. Grail's shares fell roughly 45-50% after the results were disclosed. The Galleri test's premarket approval application, submitted to the FDA on January 29, 2026, remains pending review.