EGFR and non-small cell lung carcinoma: In the phase 3 AURA3 trial38, which compared osimertinib with platinum–pemetrexed combination chemotherapy in patients with EGFR T790M-positive NSCLC following progression during prior EGFR-TKI treatment, analysis of the mechanisms of osimertinib resistance showed that 21% of the patients acquired additional compound EGFR mutations and retained the T790M mutation even after they showed osimertinib resistance39.