A blood test designed to find cancer early did not work as hoped in a major new study, according to the company that makes it.

The test, called Galleri, failed to lower the number of people diagnosed with late-stage cancer, its maker Grail announced last week.

The results are a blow to a fast-growing field that aims to catch cancer earlier, when treatment may be easier and more effective.

Galleri looks for tiny shards of cancer DNA in the blood and for more than 50 types of cancer. 

The test has been sold in the U.S. since 2021, even though it has not been approved by the U.S. Food and Drug Administration (FDA). It costs $949, and most people pay for it out of pocket.

Grail says it has sold nearly 500,000 tests, including more than 185,000 last year alone.

The study followed 142,000 healthy adults ages 50 to 77 in Britain for three years. It was run with the U.K.’s National Health Service.

Some participants received the Galleri blood test. Others did not. Researchers hoped the test would find cancer earlier, at Stages 1 or 2, instead of later, when the disease is harder to treat.

That did not happen.

There was not a significant reduction in number of cancers diagnosed at Stage 3 or Stage 4 cancer, Grail said. The study’s main goal was to show a 20% drop in advanced cancers, but that target was missed.

“This doesn’t support rollout within the American health care system,” Dr. Richard Houlston, a cancer genetics expert at the Institute of Cancer Research, told The New York Times.

Grail executives said they were still encouraged by some results. They pointed to a drop in Stage 4 cancers and a rise in Stage 3 cases, which could mean cancers were found slightly earlier.

“It’s absolutely right to say we didn’t hit the primary endpoint,” said Harpal Kumar, Grail’s chief scientific officer. “But what we did see was a very compelling clinical benefit here.”

Other experts? They weren't convinced.

The study failed — "end of story," Dr. Adewole Adamson, a cancer researcher at the University of Texas at Austin, said.

“If there was a slam dunk result, we would have seen it,” he added.

Some cancers already have reliable screening tests, like mammograms and colonoscopies. But many deadly cancers do not, which is why Galleri raised so much hope.

Still, experts emphasized that finding cancer earlier does not always mean people live longer. In addition, blood tests can also miss cancers or raise false alarms.

“You’ve got this thing hanging over your head, but you don’t know what to do about it,” said Dr. Daniel Hayes of the Rogel Cancer Center in Ann Arbor, Michigan. He described cases where a blood test suggests cancer but scans find nothing.

A new law allows Medicare to cover some cancer detection tests, but Galleri is not automatically covered. Grail has also applied for FDA approval.

Experts say the failed trial could make that approval more difficult.

These results "are really sobering for this field,” Adamson added.

After the announcement, Grail’s stock dropped about 50%. Nearly all of the company’s revenue comes from Galleri sales.