FDA panel weighs approval of first multi-cancer blood test

Test would fill screening gaps for dozens of cancer types

An FDA advisory committee that reviews medical devices convenes Wednesday to weigh whether to recommend approval of Grail’s Galleri, a blood test the company says can detect up to 50 forms of cancer from a single draw — many of them in diseases for which no routine screening exists today. No multi-cancer screening test has yet completed the FDA’s safety and accuracy review to win approval.

Approval would clear the way for Medicare reimbursement of the $949 test under a Congressional authorization covering multi-cancer detection tests once the FDA greenlights them, and would serve as a bellwether for the broader industry of companies racing to bring similar products to market. The FDA expedited its review of Galleri, which is further along in the approval process than competing products.

The panel will hear from Grail, FDA staff and members of the public before voting on a recommendation. The FDA often follows advisory committee recommendations but is not required to.

Galleri searches for genetic material and other cancer markers shed in blood. Grail says the test should be used alongside, not in place of, existing screenings such as colonoscopies and mammograms. It costs $949.

The committee’s review centers on two clinical studies — a UK National Health System trial of more than 140,000 patients and a North American trial of more than 35,000 people, all over age 50. Both studies failed to meet their primary endpoint of reducing overall mortality, and neither reduced the combined number of Stage III and Stage IV cancer diagnoses. In a subsequent update to its NHS study, Grail reported that Stage IV diagnoses alone decreased over the three-year study period, a finding the company frames as evidence that the test shifted diagnoses toward earlier stages.

The FDA’s questions for the committee focus on whether the clinical data show the test detects cancers reliably and early enough to justify claims in its marketing. The agency has signaled it may require Grail to include caveats in promotional materials — for example, warnings that a negative result does not rule out cancer and that a positive detection does not confirm it.

The financial stakes for the industry have grown since Congress authorized Medicare to cover multi-cancer detection tests once the FDA approves them. Hundreds of companies are pursuing multi-cancer blood tests, which look for cancer markers in blood or saliva.

Cristian Tomasetti, director of City of Hope cancer center’s early detection and monitoring division, called the moment pivotal. “It’s a new era for early cancer detection, and if the FDA approves it, validates the overall concept,” Tomasetti said. In 2018, Tomasetti was part of a team that developed a competing blood-test technology, the basis of a test made by Exact Sciences and since purchased by Abbott. Tomasetti is no longer involved with that company.

Tomasetti acknowledged that Galleri’s clinical trials did not meet their endpoints but said the studies set ambitious targets — particularly demonstrating mortality reductions within just three years. Mortality reductions are typically measured over longer periods, he said, and initial years of testing would surface late-stage cancers already present in the population. “This is kind of a technicality,” Tomasetti said of the missed endpoint, adding that longer-term studies are needed to confirm whether regular testing shifts diagnoses from Stage IV to earlier stages. Based on the totality of the data, Tomasetti said, he expects the FDA to approve Galleri.

Oncologist Tom Beer, chief medical officer for Abbott Cancer Diagnostics, which is developing a competing test called CancerGuard, offered a parallel assessment. “I’m keenly aware every week when I’m in the clinic, of how many patients are diagnosed with cancers that we don’t screen for,” Beer said, noting that 70 percent of cancer diagnoses and deaths come from diseases like pancreatic cancer for which no routine screening exists.

The committee’s vote is advisory. The FDA will weigh the recommendation alongside its own review before reaching a final decision on approval.