The lawsuit, filed by Hagens Berman, covers shareholders who purchased stock between May 13, 2025, and February 19, 2026. During this period, GRAIL leadership repeatedly expressed confidence that a three-year follow-up window would successfully demonstrate a reduction in late-stage cancer diagnoses. However, the company admitted after the trial’s failure that a longer follow-up period likely would have been necessary to achieve these results.

Following the announcement, GRAIL’s share price plummeted more than 50% in a single day. Reed Kathrein, a partner at Hagens Berman, is now investigating when exactly management realized their three-year projection was insufficient. The firm is currently seeking to represent affected investors and is calling for whistleblowers with internal knowledge of the trial’s design process to come forward ahead of the August 4, 2026, lead plaintiff deadline.