[wgolsen]

An interim analysis of Grail’s Pathfinder study [1] suggests a PPV of 43% [2]. This may be a mixed population of their high and normal risk cohorts - it’s not clear to me from the abstract. They call this a conservative estimate, which seems quite fair, given that the “discordant” positive cases are really only potential false positives at this point. These patients may actually harbor tumors that become detectable further into the study or on follow up.

Even with a mixed risk study population, a lower bound estimate of PPV in the 40s seems like a big win for Grail.

1 https://clinicaltrials.gov/ct2/show/NCT04241796

2 https://ascopubs.org/doi/abs/10.1200/JCO.2021.39.15_suppl.30...