The Galleri blood test failed to reduce late-stage cancer diagnoses in a huge NHS trial, missing the study’s main target when the results were presented on Saturday in Chicago. The first randomised test of the multi-cancer screening tool found no statistically significant cut in stage three or stage four cancers among people who took the test compared with those in the control group.
The finding matters now because doctors, patients and cancer researchers have been waiting for the first full readout from a study that enrolled 142,942 symptom-free NHS patients aged 50 to 77 and followed them for three years. Half had their blood analysed with Galleri once a year, while the other half had standard screening without the test, giving the trial a scale that made it the largest randomised evaluation so far of this kind of blood test.
Julie Gralow said publicly in Chicago that the results showed encouraging signs of tumour downstaging, but she stressed that the predefined primary endpoint had not been met. Prof Richard Houlston said the study’s main goal was to show a reduction in late-stage cancers overall, and that it had not done so. That is the number that will carry the most weight for anyone asking whether Galleri can move cancer detection earlier in a way that changes outcomes.
The test is marketed as a blood test for more than 50 types of cancer, and the trial was designed to see whether adding it to usual NHS screening could reduce diagnoses of stage three and stage four disease in a pre-specified group of 12 cancers. Researchers still highlighted one result they saw as positive: stage four cancers alone fell by 14%. Grail also called the findings encouraging and described Galleri as a potential transformational shift in cancer detection.
That leaves the central question open in a way that matters clinically. A 14% drop in stage four disease may help the case for the test, but the trial did not achieve the endpoint needed to show that Galleri reduced late-stage cancer diagnoses overall, and no regulatory or NHS decision was announced with the readout. For now, the largest test of its kind has shown signal, not proof.
