Background: Second-generation ALK tyrosine kinase inhibitors (TKIs) alectinib and ceritinib have demonstrated efficacy and acceptable safety in ALK TKI-pretreated and TKI-naive NSCLC. However, as with crizotinib, resistance to alectinib and ceritinib eventually develops, with secondary resistance mutations detected in approximately 50% of pts. Brigatinib is a next-generation ALK TKI designed to have potent and broad activity against ALK mutants. Post-crizotinib, brigatinib demonstrated high systemic and CNS objective response rates (ORR) and the longest reported median progression-free survival (PFS) of any ALK inhibitor in this setting (16.3–16.7 mo) (Huber. J Clin Oncol 2018;36; Bazhenova. Ann Oncol 2017;28); efficacy was demonstrated regardless of mutations. Based on nonclinical and clinical data, brigatinib may show efficacy in ALK+ NSCLC that has developed resistance or failed to respond to alectinib/ceritinib. This trial was designed to assess efficacy and safety of brigatinib in pts with ALK+ NSCLC that has progressed on alectinib or ceritinib. Methods: This is a phase 2, open-label, single-arm, multicenter, international trial (NCT03535740) in pts (≥18 y) with locally advanced/metastatic NSCLC and disease progression on alectinib or ceritinib (± prior crizotinib; ≤3 different systemic regimens for locally advanced/metastatic disease). Pts receive oral brigatinib 180 mg QD with 7-day lead-in at 90 mg QD. Treatment beyond progression or escalation to brigatinib 240 mg QD is permitted. Primary endpoint: independent review committee (IRC)−assessed confirmed ORR (cORR) per RECIST v1.1. Secondary endpoints: investigator (INV)-assessed cORR, duration of response (INV- and IRC-assessed), PFS, disease control rate, and time to response; in pts with baseline brain metastases: IRC-assessed intracranial cORR, duration of intracranial response, and intracranial PFS; OS; safety/tolerability; and HRQoL. Exploratory endpoints include biomarker analyses. The study was initiated in Dec 2018 at 78 sites (North America, Europe, Asia), with a planned sample size of 103 pts. Accrual is ongoing. Clinical trial information: NCT03535740