• Sen Zhang, Rana Anjum, Rachel Squillace, Sara Nadworny, Tianjun Zhou, Jeff Keats, Yaoyu Ning, Scott D Wardwell, David Miller, Youngchul Song, Lindsey Eichinger, Lauren Moran, Wei-Sheng Huang, Shuangying Liu, Dong Zou, Yihan Wang, Qurish Mohemmad, Hyun Gyung Jang, Emily Ye, Narayana Narasimhan, Frank Wang, Juan Miret, Xiaotian Zhu, Tim Clackson, David Dalgarno, William C Shakespeare, and Victor M Rivera.
• ARIAD Pharmaceuticals, Inc, Cambridge, Massachusetts.
• Clin Cancer Res. 2016 Nov 15; 22 (22): 5527-5538.

PurposeNon-small cell lung cancers (NSCLCs) harboring ALK gene rearrangements (ALK+) typically become resistant to the first-generation anaplastic lymphoma kinase (ALK) tyrosine kinase inhibitor (TKI) crizotinib through development of secondary resistance mutations in ALK or disease progression in the brain. Mutations that confer resistance to second-generation ALK TKIs ceritinib and alectinib have also been identified. Here, we report the structure and first comprehensive preclinical evaluation of the next-generation ALK TKI brigatinib.Experimental DesignA kinase screen was performed to evaluate the selectivity profile of brigatinib. The cellular and in vivo activities of ALK TKIs were compared using engineered and cancer-derived cell lines. The brigatinib-ALK co-structure was determined.ResultsBrigatinib potently inhibits ALK and ROS1, with a high degree of selectivity over more than 250 kinases. Across a panel of ALK+ cell lines, brigatinib inhibited native ALK (IC50, 10 nmol/L) with 12-fold greater potency than crizotinib. Superior efficacy of brigatinib was also observed in mice with ALK+ tumors implanted subcutaneously or intracranially. Brigatinib maintained substantial activity against all 17 secondary ALK mutants tested in cellular assays and exhibited a superior inhibitory profile compared with crizotinib, ceritinib, and alectinib at clinically achievable concentrations. Brigatinib was the only TKI to maintain substantial activity against the most recalcitrant ALK resistance mutation, G1202R. The unique, potent, and pan-ALK mutant activity of brigatinib could be rationalized by structural analyses.ConclusionsBrigatinib is a highly potent and selective ALK inhibitor. These findings provide the molecular basis for the promising activity being observed in ALK+, crizotinib-resistant patients with NSCLC being treated with brigatinib in clinical trials. Clin Cancer Res; 22(22); 5527-38. ©2016 AACR.©2016 American Association for Cancer Research.

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