Fig. 1

Insight into patient’s examination results and prevalence of EGFR resistance mutations. a Graph showing the molecular fractions of EGFR^T790M and EGFR^G724S normalized to EGFR^19del at first diagnosis (T0), prior to treatment with osimertinib (T1) and at progression to osimertinib (T2) in patients P1, P3, and P4. Treatment is indicated with bars below. All patients received a first-generation EGFR inhibitor (1st gen. TKI) prior to treatment with osimertinib. In P1, next-generation sequencing was not feasible at T1 and EGFR status was determined by Sanger sequencing (dotted lines). b The contrast-enhanced CT scans of patient P3 prior to treatment with osimertinib (T1) and at progression (T2) are exemplarily shown. The yellow arrows mark the spot of the biopsy collected in a growing lesion. c Prior to the start of osimertinib treatment (T2) two separate biopsies were collected (EPI, dotted line and EPII, solid line). Graph indicates the evolution of the molecular fractions of EGFR^T790M and EGFR^G724S in patient P2 prior to treatment with EGF816 (T1) and osimertinib (T2) and at progression to osimertinib (T3). d ¹⁸FDG PET-CT scans shows P2 prior to treatment (T2) and at progression to treatment with osimertinib (T3). e Bar chart showing the frequencies of EGFR mutations (EGFR^G724S and EGFR^C797S) at progression to third-generation EGFR inhibition (n = 30). f Positions of the osimertinib resistance mutations EGFR^C797S and EGFR^G724S within the binding site of the EGFR kinase domain are shown (PDB ID: 5UWD)