Grail reported that its NHS‑Galleri multicancer early detection (MCED) trial did not meet the primary endpoint of a statistically significant reduction in late‑stage (Stage III–IV) cancers. The company disclosed topline results from the 142,000‑participant England study alongside its financials, and shares plunged roughly half in after‑hours trading. Grail highlighted favorable trends in a pre‑specified group of 12 deadly cancers and a reduction in stage IV diagnoses, and said it will extend follow‑up by 6–12 months for additional maturity. Company leaders told investors they expect the FDA and payers to evaluate the totality of evidence; outside experts called the topline failure a hard setback for the MCED field. The trial outcome raises fresh questions about MCED clinical endpoints and regulatory pathways for population screening tests.