GRAIL, LLCSecurities fraud class action lawsuit alleging misleading disclosures about trial design and efficacy, causing 50% stock drop.

Hagens Berman Sobol Shapiro LLP has filed a securities fraud class action lawsuit against GRAIL, Inc., alleging the company misled investors about the design and efficacy of its NHS-Galleri cancer screening trial. The suit covers investors who purchased GRAIL common stock between May 13, 2025 and February 19, 2026, with a lead plaintiff deadline of August 4, 2026. The complaint claims GRAIL and senior executives touted a three-year follow-up period as sufficient to show a statistically significant reduction in late-stage cancer diagnoses, while concealing internal indicators that a longer timeline was needed. On February 19, 2026, GRAIL disclosed the trial failed to meet its primary endpoint and admitted it probably should have allowed for a longer follow-up, causing shares to plummet 50.55% from $101.53 to $50.21 in a single session and erasing over $2.2 billion in market capitalization. Hagens Berman is also investigating when management first knew the three-year timeline was inadequate.
GRAIL, LLCSecurities fraud class action lawsuit alleging misleading disclosures about trial design and efficacy, causing 50% stock drop.