Plasma Genotyping for EGFR-Mutant Non–Small-Cell Lung Cancer

Osimertinib, a third-generation epidermal growth factor receptor (EGFR) tyrosine-kinase inhibitor (TKI), is FDA-approved for patients with refractory non–small-cell lung cancer (NSCLC) whose tumors carry the EGFR-resistant T790M mutation. Given the difficulty of repeat tumor biopsy, plasma genotyping to detect resistant mutations is under development. Researchers (some with a pending patent on a plasma genotyping method) retrospectively compared plasma genotyping with tumor genotyping in 216 osimertinib-pretreated patients with EGFR-mutant NSCLC who had been enrolled in the AURA trial (NEJM JW Oncol Hematol Jul 2015 and N Engl J Med 2015; 372:1689).

Plasma genotyping by BEAMing (a digital polymerase-chain-reaction test) had a sensitivity of …