Based on the anti-tumor activity and favorable toxicity profile of DS-1205c in nonclinical models, the use of DS-1205c in combination with an EGFR TKI was investigated in patients with metastatic or unresectable EGFR-mutant (T790M-negative) NSCLC in a multicenter, open-label, phase 1 Japanese study. This evidence concerns the gene EGFR and non-small cell lung carcinoma.