FDA Panel to Vote on First Multi-Cancer Blood Test, Galleri

The committee of independent experts will hear from Grail, FDA officials and the public before voting on a recommendation. The FDA often follows the advice of its panels but is not required to. Approval by the agency could lead to insurance reimbursement for the test, which costs $949.

Grail says Galleri should be used alongside standard cancer screenings, such as colonoscopies and mammograms, rather than as a replacement. While blood tests for cancer already exist on the market, none that screen for multiple cancers has undergone the safety and accuracy reviews needed to win FDA approval so far. Many doctors and patients hope the technology will help detect disease earlier, when more treatment options may be possible.

Hundreds of companies are pursuing blood tests to detect cancer through a simple blood draw by looking for genetic material or other cancer markers shed in blood or saliva. The financial incentive to win FDA approval grew after Congress approved Medicare coverage for multi-cancer detection tests greenlighted by the agency. The FDA expedited its review of Galleri, which is the furthest along in the approval process and is seen as a bellwether for the industry.

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

The FDA has laid out key questions for the committee, centered on whether clinical data show the test detects cancers reliably and early enough to justify use of such terms in its marketing. The agency also wants the panel to consider harm from false results and may require the company to include caveats in its marketing, such as warnings that a false negative does not rule out the presence of cancer and that a positive detection does not signify cancer.

The advisory committee will review two major clinical studies conducted by Grail: one involving more than 140,000 patients in the UK’s National Health System and another of more than 35,000 North American patients, all over the age of 50. The interpretation of the studies has been somewhat controversial. Galleri tests did not meet their primary end point of reducing mortality overall, nor did they reduce the combined number of Stage III and IV cancers. In subsequent updates to its NHS study, Grail clarified that Stage IV cancer diagnoses, not combined with Stage III, decreased over its three-year study period, suggesting the tests may have shifted cancer diagnosis to earlier stages.

While the trials have not fully proven the test’s benefit, the key question is whether Galleri is accurate enough and can reliably catch cancers early enough to reduce deaths from cancer. Tomasetti acknowledged that Galleri’s tests did not meet their end points in clinical studies. He said that was in large part because the study specified very ambitious goals, such as showing reductions in mortality within a short period of three years; mortality reductions are typically measured over the long term. He said the short duration of the studies created other problems, including that in the initial years of testing one would expect to detect more late-stage cancers that already existed in the population.

“This is kind of a technicality,” Tomasetti said, adding that it did not mean the study, in substance, failed to show evidence of what multi-cancer detection tests can do. He said longer-term studies are needed to confirm that using the tests regularly will help shift diagnoses from Stage IV to earlier stages. Based on the totality of the data, Tomasetti said he thinks the FDA appears poised to approve Galleri. Oncologist Tom Beer, chief medical officer for Abbott Cancer Diagnostics, also agrees, according to NPR.