Alectinib (Alecensa®) is a second-generation, orally active, potent and highly selective inhibitor of anaplastic lymphoma kinase (ALK). Alectinib is approved for the treatment of ALK fusion-gene positive, unresectable, advanced or recurrent non-small cell lung cancer (NSCLC) in Japan, where it has been given orphan drug designation. Approval was based on a phase 1–2 study in ALK inhibitor-naive patients with ALK-rearranged advanced NSCLC who received twice-daily alectinib 300 mg. In the phase 2 portion, 93.5 % of patients achieved an objective response. Treatment response was rapid, with a partial response achieved in two-thirds of patients within 3 weeks (cycle 1). Patient follow-up is ongoing, and after approximately 2 years, 19.6 % of patients had achieved a complete response, and the 2-year progression-free survival rate is 76 %. During treatment with alectinib (median follow-up approximately 8 months), there was no progression of CNS lesions among patients with known CNS metastases at baseline (although prior radiation therapy may have confounded results). In preclinical models, alectinib was active against most ALK fusion-gene mutations related to crizotinib resistance, and preliminary results from clinical trials indicate efficacy in crizotinib-refractory NSCLC. Alectinib was generally well tolerated in clinical trials, and there were no treatment-related grade 4 adverse events or deaths. The most common grade 3 treatment-related adverse events were decreased neutrophil counts and increased creatinine phosphokinase. While more data are needed to confirm the efficacy of alectinib and to evaluate its activity in crizotinib-resistant disease, the drug provides a very promising option for the treatment of ALK-rearranged advanced NSCLC.