Failure of the Galleri multi-cancer detection trial to meet its primary endpoint

Cancer screening has been at the forefront of the war against cancer for decades. Yet professional organizations such as the U.S. Preventive Services Task Force (USPSTF) recommend cancer screening for only a handful of cancers (cervical, lung, colon, breast, prostate). Screening for other serious cancers (ovarian, pancreatic, etc.) is not recommended, at least for individuals with low/moderate risk. The discovery of circulating tumor DNA (ctDNA) as a non-invasive biomarker for diverse cancers prompted many companies to develop screening tests for one or more cancer types. Particularly, one test, known as "the Galleri test", marketed by Grail Inc., combined with standard of care, claims to be able to detect simultaneously 40-50 cancer types, thus potentially reducing costs. The literature on the clinical effectiveness of this test is currently controversial. Here, we comment on the results of a randomized trial that is currently ongoing in the United Kingdom, evaluating the ability of the test to meet its primary clinical endpoint. Analysis of these new data showed that the primary endpoint of the trial, aiming to reduce the incidence of stage III-IV cancer by at least 20 %, was missed. The trial is still ongoing.