Recently, the third-generation EGFR inhibitor osimertinib (Figure 1), also called AZD9291 or tagrisso, has emerged as a potential therapeutic to treat patients with metastatic EGFR T790M mutation-positive NSCLC by blocking the growth of EGFR T790M-positive tumors [23,24,25]. This evidence concerns the gene EGFR and non-small cell lung carcinoma.