MEchanisms of Resistance in EGFR Mutated Nonpretreated Advanced Lung Cancer Receiving OSimErtib

Oral administration of TAGRISSO® 80mg (Osimertinib) as a single daily dose until disease progression or unacceptable toxicity.

"Tumor biopsies performed at baseline and clinical progression will be processed (fixed) on site, and sent to Nantes University Hospital for analysis.~The following analysis will be performed:~1. Analyses performed on a regular basis, in order to allow subsequent inclusion in other clinical trials :~ * C797S testing (digital PCR)~ * MET amplification (dPCR/FISH)~ * Histological examination of the tissue sample (to identify small cell transformation)~ * Expression of proteins by immunohistochemistry: PD-L1 (Ventana SP263 antibody); CD73 ; CD4; CD8.~2. At the end of inclusions, deep sequencing analysis to identify acquired mutations and copy number variations (amplifications)."

"ctDNA analysis by Collection of plasma (two 10-ml Streck tubes) at each time point indicated in the trial.~These samples will be sent at room temperature by courier to the central laboratory (Nantes University Hospital). There they will be centrifuged, and plasma will be frozen (-80°C).~Analyses :~* Detection of the EGFR activating mutation in plasma at baseline By dPCR (characterization of patients enrolled)~* Detection of the EGFR activating mutation at d7 and m1 by dPCR (early detection of response to osimertinib)~* Analysis of the plasma samples collected at clinical progression in order to identify acquired mechanisms of resistance by NGS (and comparison with analysis of the biopsies).~* Kinetics studies of the alterations"