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LUNG CANCER: Osimertinib versus Comparator EGFR Tyrosine Kinase Inhibitor as First-Line Treatment in Patients with EGFR-Mutated Advanced Non–Small Cell Lung Cancer


Nov. 25, 2019


American Association for Cancer Research https://doi.org/10.1158/1078-0432.CCR-19-1126

In a comparison of tissue versus ctDNA testing at diagnosis for NSCLC, ctDNA analysis (cobas) missed 21% of EGFR exon 19 and 32% of EGFR L858R variants.


To assess the utility of the cobas EGFR Mutation Test, with tissue and plasma, for first-line osimertinib therapy for patients with EGFR-mutated (EGFRm; Ex19del and/or L858R) advanced or metastatic non–small cell lung cancer (NSCLC) from the FLAURA study (NCT02296125).

Patients and Methods:

Tumor tissue EGFRm status was determined at screening using the central cobas tissue test or a local tissue test. Baseline circulating tumor (ct)DNA EGFRm status was retrospectively determined with the central cobas plasma test.


Our results support utility of cobas tissue and plasma testing to aid selection of patients with EGFRm advanced NSCLC for first-line osimertinib treatment. Lack of EGFRm detection in plasma was associated with prolonged PFS versus patients plasma EGFRm positive, potentially due to patients having lower tumor burden.