Hello everyone. Earlier this week, an FDA advisory committee ultimately voted to recommend the agency approve Grail’s Galleri liquid biopsy test for cancer. You can check out Matt Herper’s story here. There were a few sticking points during the deliberations, including whether the test could be rightfully called an early detection test, since its performance drops precipitously in earlier stages of diagnosis.
"The term early, it’s so fraught. Earlier than what?" said Charity Morgan, a biostatistician from the University of Alabama, during the meeting. "We saw the sensitivity going down for lower stages versus later stages. That tells me it’s not for early detection. It’s for later detection."
There were also serious concerns over how the test would be used and interpreted by the general public. For Guardant’s Shield test, gastroenterologists feared people would rely only on liquid biopsy and forgo screening methods that can detect cancers early. Similarly, experts on the panel worried negative Galleri tests would give people "false reassurance, and people not doing guideline directed screening," as Jason Dominitz, a gastroenterologist from the University of Washington, put it.
The panel voted unanimously that the test was "safe," but was split 6-4 on whether it was effective. It was 7 yes, 2 no, and 1 abstain on whether the test’s benefits outweigh the risks. Some of the reasons for voting yes included that though Galleri is not a perfect test, that shouldn’t necessarily stand in the way of progress. This test could change the lives for some individuals who have cancers that have no other screening method, and could be beneficial as purely a supplement to guideline recommended screening.
For me, this is a really interesting moment for cancer detection and liquid biopsy. That’s because the debate over whether these tests are ready for "primetime" has been going on for years now, and the door seemed nearly shut after Grail’s large NHS-Galleri trial failed to meet its primary endpoint. But if the FDA goes forward with approving the test and following the recommendation, that door swings open.
