Reviewing randomized studies using EGFR- or ALK-TKIs in the first-line context for advanced EGFR- or ALK-positive NSCLC, respectively, revealed that 4 to 10% of newly diagnosed patients experience primary resistance, which is defined as "progressive disease as the best response" (481, 482, 483, 484, 485, 486, 487). Here, EGFR is linked to non-small cell lung carcinoma.