As part of its bid to transform the future of cancer screening and seize control of a potentially vast and increasingly competitive market, Grail announced fresh data on Friday from a large U.S. study of its flagship blood-based test for detecting dozens of tumor types. The results reinforce some of the company’s arguments for a new approach to screening; experts said the firm seems to have improved the test’s accuracy but noted that major questions about the real-world impacts of such tests remain.

The Pathfinder 2 study enrolled nearly 36,000 adults over the age of 50 to evaluate the biotech’s screening test, Galleri. When researchers measured the test’s performance in participants who’d been followed for over a year, they found that it caught 40.4% of cancer cases, a test feature known

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