Cancer-Detection Blood Tests Gain Ground

"Blood tests designed to detect cancer at early stages are reaching tens of thousands of people, as developers vie for a piece of what they expect to be a lucrative new market in healthcare.

Illumina Inc.'s Grail unit said more than 38,000 people have used its $949 blood test since it went on sale in the U.S. in June 2021, with many of them paying out of pocket because their insurance doesn't cover it. The tests have helped clinicians diagnose some 100 patients with a range of cancers, most of which don't have a recommended screening test, according to company data.

Grail and rivals including Exact Sciences Corp., Freenome Holdings Inc. and Guardant Health Inc. have started studies of similar tests that aim to enroll tens of thousands of people. The companies said they hope to generate sufficient evidence of their accuracy and utility to secure approval from the Food and Drug Administration. The FDA declined to comment.

The tests are at the heart of regulatory fights in the U.S. and Europe, where regulators have raised concerns about competition in the field in their attempts to unwind Illumina's $7.1 billion acquisition of Grail in 2021. Illumina, which makes the gene-sequencing machines that Grail and its rivals use to process blood tests, is fighting the antitrust efforts but said it is exploring options for Grail that could include a divestiture.

The tests, also known as liquid biopsies, could augment the few established screening tools, such as mammograms for breast cancer and colonoscopies for colorectal cancer. And they could become sentinels for other tumor types that lack validated screens. SVB Securities analyst Puneet Souda estimates they could eventually generate $50 billion in annual sales.

Researchers have long known that DNA and other biological markers of tumors circulate in the blood, and doctors have started using blood-based tests to manage care for some patients already diagnosed with cancer. Improvements in the gene-based technology behind the tests have moved the field closer to a long-held goal: blood tests that can detect cancers at their earliest stages, when treatment might lead to better outcomes.

The field is young, and there are limits to the accuracy of the tests, cancer researchers and doctors said.

The tests haven't been proved to prolong the average survival of cancer patients.

They miss cancers in some people and incorrectly flag it in others, studies have shown, though they have a lower rate of false positives than false negatives. Some doctors said the tests could lead to unnecessary follow-up or risky treatment for slow-growing tumors.

"We're excited about the potential that these tests offer, concerned that we don't have enough data at this time to really understand how best to use them," said Lori Minasian, deputy director for the Division of Cancer Prevention at the National Cancer Institute.

The NCI said it plans to start enrolling some 24,000 people in 2024 for an initial study of the tests, before a larger trial that will include as many as 225,000 people.

Grail, based in Menlo Park, Calif., in September released results of a study of its Galleri test showing that among some 6,600 patients 50 and over, a cancer signal was positive in 92 participants. Among those with a positive test, about 38%, or 35 people, were diagnosed with cancer within 12 months.

The test returned a false positive in less than 1% of people screened in the trial. About 30% of those people underwent an invasive procedure such as an endoscopy or a biopsy. No serious adverse events were reported, the company said.

An additional 85 people in the trial had their cancers caught through other screening or because they developed symptoms. Earlier data from 2021 suggest that the test is better at detecting cancers at later stages.

Vincere Cancer Center in Scottsdale, Ariz., is using Galleri tests to screen first responders, who are at elevated risk for some cancers from exposure to carcinogens such as diesel fumes or asbestos. The test has caught cancers that other screening missed, said Pablo Prichard, the center's co-founder. It has also missed some cancers that were caught with other tools.

"It's not a stand alone. It's a great complementary test," he said." [1]

 

  It is surprising that survival is not improved. In theory, the earlier cancer cells are detected and removed, the fewer of them are left to participate in the selection process that results in formation of the most resistant to therapy cells.

 

1. U.S. News: Cancer-Detection Blood Tests Gain Ground
Loftus, Peter; Abbott, Brianna. 
Wall Street Journal, Eastern edition; New York, N.Y. [New York, N.Y]. 08 Oct 2022: A.3.