EGFR Genotyping of Matched Urine, Plasma, and Tumor Tissue in Patients With Non–Small-Cell Lung Cancer Treated With Rociletinib, an EGFR Tyrosine Kinase Inhibitor

PurposeLiquid biopsies represent an attractive alternative to tissue biopsies, particularly rebiopsies, in determining patient eligibility for targeted therapies. Clinical utility of urine genotyping, however, has not been explored extensively. We evaluated epidermal growth factor receptor (EGFR) T790M detection in matched urine, plasma, and tissue and the clinical outcomes of patients with advanced non–small-cell lung cancer treated with rociletinib.MethodsTissue (n = 540), plasma (n = 482), and urine (n = 213) were collected from evaluable patients enrolled in TIGER-X, a phase I/II study. Genotyping was performed by therascreen EGFR testing in tissue, BEAMing in plasma, and a quantitative short footprint assay (Trovera) in urine, which was used to further examine discordant samples.ResultsPositive percent agreement with tissue T790M results was similar for urine (82%; 142 of 173) and plasma (81%; 313 of 387) genotyping. Urine and plasma together identified more patients who were T790M positive (92%) tha...