Brigatinib in Crizotinib-Refractory ALK+ NSCLC: 2-Year Follow-up on Systemic and Intracranial Outcomes in the Phase 2 ALTA Trial

Abstract

Introduction: We report updated data from a phase 2 randomized study evaluating brigatinib in crizotinib-refractory anaplastic lymphoma kinase-positive NSCLC. Methods: Patients were randomized 1:1 to take either oral brigatinib 90 mg once daily (arm A) or 180 mg once daily with a 7-day lead-in at 90 mg (arm B), stratified by central nervous system (CNS) metastases and best response to crizotinib. The primary end point was investigator-assessed confirmed objective response rate per Response Evaluation Criteria in Solid Tumors version 1.1. Secondary end points included independent review committee (IRC)-assessed progression-free survival (PFS), intracranial PFS (iPFS), and overall survival (OS). Exploratory analyses included CNS versus ex-CNS target lesion response and correlation of depth of response with PFS and OS. Results: Among 222 randomized patients (112 and 110 in arms A and B, respectively), 59 (27%) remained on brigatinib at analysis (median follow-up: 19.6 versus 24.3 months). At baseline, 71% and 67% had brain lesions among A and B arms, respectively. Investigator-assessed confirmed objective response rate was 46% versus 56%. Median IRC-assessed PFS was 9.2 months (95% confidence interval: 7.4-12.8) versus 16.7 months (11.6-21.4). Median OS was 29.5 months (18.2-not reached) versus 34.1 months (27.7-not reached). IRC-confirmed intracranial objective response rate in patients with measurable baseline brain lesions was 50% (13 of 26) versus 67% (12 of 18); median duration of intracranial response was 9.4 versus 16.6 months. IRC-assessed iPFS was 12.8 versus 18.4 months. Across arms, median IRC-assessed PFS was 1.9, 5.5, 11.1, 16.7, and 15.6 months for patients with no, 1%-25%, 26%50%, 51%-75%, and 76%-100% target lesion shrinkage, respectively. No new safety findings were observed with longer follow-up. Conclusions: Brigatinib (180 mg once daily with lead-in) continues to demonstrate robust PFS, long iPFS and duration of intracranial response, and high intracranial objective response rate in crizotinib-refractory patients. Depth of response may be an important end point to capture in future targeted therapy trials. (C) 2019 International Association for the Study of Lung Cancer. Published by Elsevier Inc.