Background: Lorlatinib, a potent, brain-penetrant, third-generation anaplastic lymphoma kinase (ALK) tyrosine kinase inhibitor (TKI), has substantial activity against ALK-positive non-small-cell lung cancer (NSCLC). This study assessed the overall, intracranial, and extracranial efficacy of lorlatinib in ALK-positive NSCLC that progressed on second-generation ALK TKIs., Patients and Methods: In the ongoing phase II study (NCT01970865), patients with ALK-positive advanced NSCLC treated with ≥1 prior second-generation ALK TKI ± chemotherapy were enrolled in expansion cohorts (EXP) based on treatment history. Overall, intracranial and extracranial antitumor activity were assessed independently per modified Response Evaluation Criteria in Solid Tumors (RECIST) v1.1., Results: Of the 139 patients with ≥1 prior second-generation ALK TKI (EXP3B-5), 28 received one prior second-generation ALK TKI (EXP3B), 65 two prior ALK TKIs (EXP4), and 46 three prior ALK TKIs (EXP5). In EXP3B-5, the objective response rate (ORR) [95% confidence intervals] was 39.6% (31.4-48.2), intracranial ORR (IC-ORR) was 56.1% (42.4-69.3), extracranial ORR (EC-ORR) was 36.7% (28.7-45.3), median duration of response (DOR) was 9.6 months [5.6-16.7; IC-DOR, 12.4 (6.0-37.1); EC-DOR, 9.7 (6.1-33.3)], median progression-free survival was 6.6 (5.4-7.4) months, and median overall survival was 20.7 months (16.1-30.3). In EXP3B, the ORR was 42.9% (24.5-62.8), the IC-ORR was 66.7% (29.9-92.5), and the EC-ORR was 32.1% (15.9-52.4). In EXP4 and EXP5, the ORR was 38.7% (29.6-48.5), the IC-ORR was 54.2% (39.2-68.6), and the EC-ORR was 37.8% (28.8-47.5)., Conclusions: Lorlatinib had clinically meaningful intracranial and extracranial antitumor activity in the post-second-generation ALK TKI setting, with elevated intracranial versus extracranial ORR, particularly in patients with fewer lines of therapy., Competing Interests: Disclosure EF has served on advisory boards for AbbVie, Bayer, Blueprint Medicines, GlaxoSmithKline, Guardant Health, Janssen, Merck KGaA, and Samsung; speakers' bureaus for Medscape, prIME Oncology, and TouchIME; advisory boards and speakers' bureaus for AstraZeneca, Boehringer Ingelheim, Bristol-Myers Squibb, Eli Lilly, Merck Sharp & Dohme, Novartis, Pfizer, Roche, and Takeda; and received research funding from Fundación Merck Salud and Grant for Oncology Innovation; independent member of the board for Grifols. ATS has served as a compensated consultant or received honoraria from Achilles, Archer, Ariad/Takeda, Bayer, Blueprint Medicines, Chugai, Daiichi-Sankyo, EMD Serono, Foundation Medicine, Guardant, Ignyta, KSQ Therapeutics, Loxo Oncology, Natera, Novartis, Pfizer, Roche-Genentech, Servier, Syros, Taiho Pharmaceutical, and TP Therapeutics; received institutional research funding from Ariad, Ignyta, Novartis, Pfizer, Roche-Genentech, and TP Therapeutics; received travel support from Genentech and Pfizer; and is currently an employee of Novartis. AB has received honoraria from AstraZeneca, Boehringer Ingelheim, Janssen, Novartis, Pfizer, Roche, and Takeda. DRC has received honoraria from AbbVie, Achilles Therapeutics, Apollomics, Archer, Arrys/Kyn, AstraZeneca, BeyondSpring Pharmaceuticals, Biothera, Blueprint Medicines, Bristol-Myers Squibb, CBT Pharmaceuticals, Daiichi-Sankyo, Elevation, EMD Serono, G1 Therapeutics, Hansoh, Helsinn Therapeutics, Hengrui Pharmaceutical, Inivata, Lilly, Medtronic, Regeneron, Ribon Therapeutics, Roche, and Takeda; and received research funding from Takeda. BJS has served as a consultant or on advisory boards for Amgen, AstraZeneca, Bristol-Myers Squibb, Merck, Novartis, Pfizer, and Roche-Genentech. JRB has served as a consultant for Astra Zeneca and Pfizer; has served on advisory boards for Bayer and Kura; and received institutional research funding from Bristol-Myers Squibb, unrelated to this work. TMB reports employment by Tennessee Oncology; has served as a consultant/advisor for Bayer, Blueprint Medicines, Exelixis, Foundation Medicine, Guardant Health, Ignyta, Loxo Oncology, Moderna Therapeutics, and Pfizer; has served on speakers' bureaus for Bayer, Bristol-Myers Squibb, and Lilly; received research funding from AbbVie, Aileron Therapeutics, Amgen, ARMO BioSciences, Astellas Pharma, Astra Zeneca, Boehringer Ingelheim, Bristol-Myers Squibb, Calithera Biosciences, Clovis Oncology, Daiichi-Sankyo, Deciphera, Five Prime Therapeutics, Foundation Medicine, Genentech/Roche, GlaxoSmithKline, Ignyta, Immunocore, Immunogen, Incyte, Jacobio, Janssen, Karyopharm Therapeutics, Kolltan Pharmaceuticals, Leap Therapeutics, Lilly, Loxo Oncology, MabVax, MedImmune, Medpacto, Inc., Merck, Merrimack, Millennium, Mirati Therapeutics, Moderna Therapeutics, Novartis, Onyx, Peleton, Pfizer, Phosplatin Therapeutics, Principia Biopharma, Roche, Sanofi, Stemline Therapeutics, Takeda, and Top Alliance BioSciences; and compensation for travel, accommodations, and expenses from Astellas Pharma, AstraZeneca, Celgene, Clovis Oncology, EMD Serono, Genentech, Lilly, Merck, Novartis, Pfizer, Pharmacyclics, and Sysmex. SP has received education grants, provided consultation, attended advisory boards, and/or provided lectures for AbbVie, Amgen, AstraZeneca, Bayer, Biocartis, BioInvent, Blueprint Medicines, Boehringer Ingelheim, Bristol-Myers Squibb, Clovis, Daiichi-Sankyo, Debiopharm, Eli Lilly, F. Hoffmann-La Roche, Foundation Medicine, Illumina, Janssen, Merck Sharp and Dohme, Merck Serono, Merrimack, Novartis, Pharma Mar, Pfizer, Regeneron, Sanofi, Seattle Genetics, Takeda, and Vaccibody, from whom she has received honoraria (all fees to institution). FT, AA report employment by Pfizer. HT, GP, RW report employment by Pfizer and are Pfizer shareholders. BB reports sponsored research at Gustave Roussy Cancer Center, AbbVie, Amgen, AstraZeneca, BeiGene, Blueprint Medicines, Bristol-Myers Squibb, Boehringer Ingelheim, Celgene, Cristal Therapeutics, Daiichi-Sankyo, Eli Lilly, GlaxoSmithKline, Ignyta, IPSEN, Inivata, Janssen, Merck KGaA, MSD, Nektar, Onxeo, OSE immunotherapeutics, Pfizer, Pharma Mar, Roche-Genentech, Sanofi, Servier, Spectrum Pharmaceuticals, Takeda, Tiziana Pharma, and Tolero Pharmaceuticals. 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To gain access, data requestors must enter into a data access agreement with Pfizer., (Copyright © 2021 The Author(s). Published by Elsevier Ltd.. All rights reserved.)