OBJECTIVES: To describe the real-world treatment patterns and economic burden of patients with ALK+ NSCLC treated with second-line ALK inhibitors. METHODS: This retrospective study used the Optum Research database to identify adult patients with a lung cancer diagnosis code (≥1 inpatient claim or ≥2 outpatient claims ≥30 days but ≤1 year apart) and use of a second-line ALK inhibitor (alectinib or ceritinib) after crizotinib, between January 2011 and March 2017. Study outcomes were time to discontinuation of second-line ALK inhibitors and probability of continued use at 6 months. Healthcare costs (2016 USD) were investigated in a subgroup analysis that included patients who had continuous enrollment in medical and pharmacy benefits for 6 months prior to second-line ALK inhibitor treatment. RESULTS: