The randomized, open-label, phase 3 study demonstrated superior efficacy and lower toxicity with alectinib compared with crizotinib, thus leading to alectinib becoming the first-line therapy for anaplastic lymphoma kinase rearrangement–positive NSCLC per National Comprehensive Cancer Network guidelines and displacing all other anaplastic lymphoma kinase inhibitors at the time of its approval. The gene discussed is ALK; the disease is non-small cell lung carcinoma.