EGFR and neoplasm: In order to identify AURA3 patients whose tumours harbour a subclonal T790M mutation, we first evaluated the prevalence and level of detection of the activating EGFR mutations, exon 19 deletion (ex19del) and L858R, and the TKI-resistant EGFR T790M in plasma collected at baseline using a clinically validated NGS-based cell-free DNA (cfDNA) assay (Supplementary Table 1; details in ‘Methods').