Grail reported that its multi‑cancer blood test showed encouraging signals but did not meet the primary endpoint in a major UK study carried out with the National Health Service, sending the company’s stock sharply lower. Management said secondary analyses show potential but acknowledged the setback undermines the test’s pivotal evidence package. Galleri has generated commercial sales but lacks FDA approval; the negative study complicates the path to regulatory clearance and payor adoption for multi‑cancer early detection assays. The results have reignited scrutiny over performance standards and clinical utility in the multi‑cancer screening market.