Grail reported that its large NHS-Galleri multicancer early detection (MCED) trial did not meet the primary endpoint of a statistically significant reduction in late-stage (III–IV) cancer diagnoses. The company said the study enrolled roughly 142,000 participants and observed "favorable trends" in a pre-specified group of 12 deadly cancers, and will extend follow-up by 6–12 months to allow data to mature. Grail emphasized the trial findings do not, in its view, automatically alter its ongoing regulatory engagement with the FDA or commercial strategy; management signaled the company will expand US sales and medical teams and submit fuller data to ASCO. Independent experts highlighted the trial’s complexity and raised questions about design and enrollment strategy. MCED refers to blood tests that screen for cancer-associated signals across many tumor types rather than a single cancer site. Market reaction was immediate: investors sold the stock sharply on the topline miss and uncertainty over the test’s impact on clinical outcomes. Grail plans additional analyses and extended follow-up to seek stronger evidence of stage shift and mortality benefit.