In this context, we report the case of a never-smoking female patient with advanced lung adenocarcinoma harboring the EGFR A767_V769dup exon 20 insertion who achieved prolonged survival (approximately 37 months) with sequential high-dose third-generation EGFR-TKIs: osimertinib 160 mg once daily followed by furmonertinib 240 mg once daily. This evidence concerns the gene EGFR and lung adenocarcinoma.