GRAIL (GRAL) stock slides as NHS-Galleri trial fails primary endpoint

GRAIL shares declined on February 20, 2026, after the company announced its NHS-Galleri trial missed the primary endpoint for multi-cancer screening. The study, conducted with the UK's National Health Service, failed to meet statistical targets for early cancer detection. This setback challenges the commercial viability of the Galleri test within public health sectors and raises concerns about future revenue streams for the diagnostic firm.