To assess the utility of the cobas®
EGFR Mutation Test, with tissue and plasma, for first-line osimertinib therapy for patients with EGFR
m) (Ex19del and/or L858R) advanced or metastatic non-small cell lung cancer (NSCLC) from the FLAURA study (NCT02296125).
Tumor tissue EGFR
m status was determined at screening using the central cobas tissue test or a local tissue test. Baseline circulating tumor (ct)DNA EGFR
m status was retrospectively determined with the central cobas plasma test.
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 EGFR
m 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 EGFR
m positive tissue test). In both treatment arms, PFS was prolonged in plasma ctDNA EGFR
m negative (23.5 and 15.0 months,) vs positive patients (15.2 and 9.7 months).
Our results support utility of cobas tissue and plasma testing to aid selection of patients with EGFR
m advanced NSCLC for first-line osimertinib treatment. Lack of EGFR
m detection in plasma was associated with prolonged PFS vs patients plasma EGFR
m positive, potentially due to patients having lower tumor burden.