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Sos ML, Tumbrink HL, Schultz-Fademrecht C, Lategahn J, Keul M, Niggenaber J, Heimsoeth A, Baumann M, Werr LH, Degenhart C, Menninger S, Heuckmann JM, Thomas RK, Rauh D, Klebl B. Targeting EGFR Ex20 mutant lung cancer with the wild type sparing kinase inhibitor PRB001. J Clin Oncol 2019. [DOI: 10.1200/jco.2019.37.15_suppl.e14718] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
e14718 Background: The majority of EGFR mutant tumors can be effectively treated with targeted drugs. Lung adenocarcinoma patients with EGFR Ex20 insertion mutations, however, lack safe and potent treatment options. These genetic alterations share homology with HER2 Ex20 insertion mutations and perturb the ATP binding pocket in a way that limits accessibility through currently available tyrosine kinase inhibitors. Second-generation EGFR inhibitors are partially active in EGFR Ex20 mutant models but their potent activity against wild type (WT) EGFR and the resulting adverse effects largely prohibit the clinical use of these drugs. To address this medical need, we developed PRB001, a novel EGFR kinase inhibitor. Methods: We facilitated protein X-ray crystallography to guide the development of small molecule inhibitors with high potency against EGFR/HER2 Ex20 mutant kinases and low activity against WT EGFR. Iterative compound optimization involved biochemical profiling concerning inhibition and binding kinetics, cellular profiling as well as mouse pharmacokinetic and mouse efficacy studies. Results: PRB001 exhibits potent activity against EGFR/HER2 Ex20 insertion mutations, in genetically engineered Ba/F3 cell line models and patient derived cell lines. At the same time, PRB001 exhibits a 10-100 fold lower activity against WT EGFR in several cellular models. Our data indicate that PRB001 and its derivatives display a therapeutic window for an effective treatment of EGFR Ex20 mutant tumors with a limited toxicity profile. Mouse xenograft experiments support these results, showing that, in contrast to second-generation EGFR inhibitors, PRB001 does not inhibit WT EGFR and does not lead to loss of weight of treated animals at effective doses of 90 mg/kg daily. Conclusions: Our data support the notion that PRB001 effectively kills a wide range of EGFR Ex20 mutant cellular models and together with its safety profile builds a basis for the development of a mutant-selective and clinically effective tyrosine kinase inhibitor.
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Affiliation(s)
- Martin L. Sos
- Department of Translational Genomics, University of Cologne, Cologne, Germany
| | - Hannah Lea Tumbrink
- Center for Molecular Medicine Cologne, University of Cologne, 50931 Cologne, Germany, Cologne, Germany
| | | | - Jonas Lategahn
- Faculty of Chemistry and Chemical Biology, TU Dortmund University, Dortmund, Germany
| | - Marina Keul
- Faculty of Chemistry and Chemical Biology, TU Dortmund University, Dortmund, Germany
| | - Janina Niggenaber
- Faculty of Chemistry and Chemical Biology, TU Dortmund University, Dortmund, Germany
| | - Alena Heimsoeth
- Molecular Pathology, Institute of Pathology, University Hospital of Cologne, Cologne, Germany
| | | | - Lisa Hanna Werr
- Department of Translational Genomics, Center of Integrated Oncology Cologne Bonn, Medical Faculty, Cologne, Germany
| | | | | | | | - Roman K. Thomas
- Department of Translational Genomics, Center of Integrated Oncology Cologne–Bonn, Medical Faculty, University of Cologne, Cologne, Germany
| | - Daniel Rauh
- Faculty of Chemistry and Chemical Biology, TU Dortmund University, Dortmund, Germany
| | - Bert Klebl
- Lead Discovery Center GmbH, Dortmund, Germany
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