Gail's Law will require insurance companies to cover additional breast cancer screenings for women with dense breasts.

Feb 20 (Reuters) - Grail shares plunged nearly 50% in premarket trading on Friday after its three-year cancer screening trial failed to meet its main goal, dealing a major blow to the blood test maker.

Grail said Galleri, its multi-cancer early detection test, failed to meet the primary endpoint of a recent trial. The stock slid 47%, to $54.20, in after-hours trading. Through market close, share have surged 93% in the past year.

Bills to extend postpartum Medicaid coverage and cover more breast cancer screenings will get a vote after they seemed doomed to fail.