PURPOSE
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).
EXPERIMENTAL DESIGN
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.
RESULTS
f 994 patients screened, 556 were randomized (289 and 267 with central and local
EGFR test results, respectively) and 438 failed screening. Of those randomized from local
EGFR test results, 217 patients had available central test results; 211/217 (97%) were retrospectively confirmed
EGFRm positive by central cobas tissue test. Using reference central cobas tissue test results, positive percent agreements with cobas plasma test results for Ex19del and L858R detection were: 79% (95% CI, 74-84) and 68% (95% CI, 61-75), respectively. Progression-free survival (PFS) superiority with osimertinib over comparator EGFR-TKI remained consistent irrespective of randomization route (central/local
EGFRm positive tissue test). In both treatment arms, PFS was prolonged in plasma ctDNA
EGFRm negative (23.5 and 15.0 months,) vs positive patients (15.2 and 9.7 months).
CONCLUSIONS
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 vs patients plasma
EGFRm positive, potentially due to patients having lower tumor burden.