By Callum Keown

Grail stock plunged around 50% in after-hours trading Thursday after the biotech company's cancer trial results disappointed investors.

The biotech company said its multi-cancer screening test Galleri did not lead to a "statistically significant reduction" in stage 3 and 4 cancer in a U.K. National Health Service $(NHS)$ trial of more than 142,000 people between the ages of 50 and 77.

Galleri is a blood test, developed by Grail, to screen for a number of cancers before they become symptomatic.

However, Grail said there was a "favorable trend" toward fewer stage 3 and 4 cancers in a group of 12 deadly cancers, as well as an increase in diagnoses of early stage cancer types that are typically detected later.

But the trial ultimately failed to achieve its primary objective--a statistically significant reduction in late stage cancer. The shares tumbled 48% to $52.25 after the market closed -- the stock has jumped more than 200% over the past six months as of Thursday's close.

Grail submitted a premarket approval application to the U.S. Food and Drug Administration in January. The company added that results from the first year of the NHS trial were included in the submission.

The biotech company also reported earnings late Thursday, which were largely overshadowed by the trial results. Grail posted a narrower-than-expected loss of $2.44 per share in the fourth quarter, while revenue of $43.6 million was in line with Wall Street estimates.

Write to Callum Keown at callum.keown@dowjones.com

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February 20, 2026 04:06 ET (09:06 GMT)

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