title: Overcoming EGFR(T790M) and EGFR(C797S) resistance with mutant-selective allosteric inhibitors.
abstract: The epidermal growth factor receptor (EGFR)-directed tyrosine kinase inhibitors (TKIs) gefitinib, erlotinib and afatinib are approved treatments for non-small cell lung cancers harbouring activating mutations in the EGFR kinase, but resistance arises rapidly, most frequently owing to the secondary T790M mutation within the ATP site of the receptor. Recently developed mutant-selective irreversible inhibitors are highly active against the T790M mutant, but their efficacy can be compromised by acquired mutation of C797, the cysteine residue with which they form a key covalent bond. All current EGFR TKIs target the ATP-site of the kinase, highlighting the need for therapeutic agents with alternative mechanisms of action. Here we describe the rational discovery of EAI045, an allosteric inhibitor that targets selected drug-resistant EGFR mutants but spares the wild-type receptor. The crystal structure shows that the compound binds an allosteric site created by the displacement of the regulatory C-helix in an inactive conformation of the kinase. The compound inhibits L858R/T790M-mutant EGFR with low-nanomolar potency in biochemical assays. However, as a single agent it is not effective in blocking EGFR-driven proliferation in cells owing to differential potency on the two subunits of the dimeric receptor, which interact in an asymmetric manner in the active state. We observe marked synergy of EAI045 with cetuximab, an antibody therapeutic that blocks EGFR dimerization, rendering the kinase uniformly susceptible to the allosteric agent. EAI045 in combination with cetuximab is effective in mouse models of lung cancer driven by EGFR(L858R/T790M) and by EGFR(L858R/T790M/C797S), a mutant that is resistant to all currently available EGFR TKIs. More generally, our findings illustrate the utility of purposefully targeting allosteric sites to obtain mutant-selective inhibitors.
authors.affiliation: Genomics Institute of the Novartis Research Foundation, San Diego, California 92121, USA.
authors.forename: Yong
authors.initials: Y
authors.lastname: Jia
authors.affiliation: Department of Cancer Biology, Dana-Farber Cancer Institute, Boston, Massachusetts 02215, USA.|Department of Biological Chemistry and Molecular Pharmacology, Harvard Medical School, Boston, Massachusetts 02115, USA.
authors.forename: Cai-Hong
authors.initials: CH
authors.lastname: Yun
authors.affiliation: Department of Cancer Biology, Dana-Farber Cancer Institute, Boston, Massachusetts 02215, USA.|Department of Biological Chemistry and Molecular Pharmacology, Harvard Medical School, Boston, Massachusetts 02115, USA.
authors.forename: Eunyoung
authors.initials: E
authors.lastname: Park
authors.affiliation: Lowe Center for Thoracic Oncology, Dana-Farber Cancer Institute, Boston, Massachusetts 02215, USA.
authors.forename: Dalia
authors.initials: D
authors.lastname: Ercan
authors.affiliation: Genomics Institute of the Novartis Research Foundation, San Diego, California 92121, USA.
authors.forename: Mari
authors.initials: M
authors.lastname: Manuia
authors.affiliation: Genomics Institute of the Novartis Research Foundation, San Diego, California 92121, USA.
authors.forename: Jose
authors.initials: J
authors.lastname: Juarez
authors.affiliation: Lowe Center for Thoracic Oncology, Dana-Farber Cancer Institute, Boston, Massachusetts 02215, USA.
authors.forename: Chunxiao
authors.initials: C
authors.lastname: Xu
authors.affiliation: Lowe Center for Thoracic Oncology, Dana-Farber Cancer Institute, Boston, Massachusetts 02215, USA.
authors.forename: Kevin
authors.initials: K
authors.lastname: Rhee
authors.affiliation: Lowe Center for Thoracic Oncology, Dana-Farber Cancer Institute, Boston, Massachusetts 02215, USA.
authors.forename: Ting
authors.initials: T
authors.lastname: Chen
authors.affiliation: Lowe Center for Thoracic Oncology, Dana-Farber Cancer Institute, Boston, Massachusetts 02215, USA.
authors.forename: Haikuo
authors.initials: H
authors.lastname: Zhang
authors.affiliation: Belfer Center for Applied Cancer Science, Dana-Farber Cancer Institute, Boston, Massachusetts 02215, USA.
authors.forename: Sangeetha
authors.initials: S
authors.lastname: Palakurthi
authors.affiliation: Department of Cancer Biology, Dana-Farber Cancer Institute, Boston, Massachusetts 02215, USA.|Department of Biological Chemistry and Molecular Pharmacology, Harvard Medical School, Boston, Massachusetts 02115, USA.
authors.forename: Jaebong
authors.initials: J
authors.lastname: Jang
authors.affiliation: Genomics Institute of the Novartis Research Foundation, San Diego, California 92121, USA.
authors.forename: Gerald
authors.initials: G
authors.lastname: Lelais
authors.affiliation: Genomics Institute of the Novartis Research Foundation, San Diego, California 92121, USA.
authors.forename: Michael
authors.initials: M
authors.lastname: DiDonato
authors.affiliation: Genomics Institute of the Novartis Research Foundation, San Diego, California 92121, USA.
authors.forename: Badry
authors.initials: B
authors.lastname: Bursulaya
authors.affiliation: Genomics Institute of the Novartis Research Foundation, San Diego, California 92121, USA.
authors.forename: Pierre-Yves
authors.initials: PY
authors.lastname: Michellys
authors.affiliation: Genomics Institute of the Novartis Research Foundation, San Diego, California 92121, USA.
authors.forename: Robert
authors.initials: R
authors.lastname: Epple
authors.affiliation: Genomics Institute of the Novartis Research Foundation, San Diego, California 92121, USA.
authors.forename: Thomas H
authors.initials: TH
authors.lastname: Marsilje
authors.affiliation: Genomics Institute of the Novartis Research Foundation, San Diego, California 92121, USA.
authors.forename: Matthew
authors.initials: M
authors.lastname: McNeill
authors.affiliation: Genomics Institute of the Novartis Research Foundation, San Diego, California 92121, USA.
authors.forename: Wenshuo
authors.initials: W
authors.lastname: Lu
authors.affiliation: Genomics Institute of the Novartis Research Foundation, San Diego, California 92121, USA.
authors.forename: Jennifer
authors.initials: J
authors.lastname: Harris
authors.affiliation: Genomics Institute of the Novartis Research Foundation, San Diego, California 92121, USA.
authors.forename: Steven
authors.initials: S
authors.lastname: Bender
authors.affiliation: Lowe Center for Thoracic Oncology, Dana-Farber Cancer Institute, Boston, Massachusetts 02215, USA.|Belfer Center for Applied Cancer Science, Dana-Farber Cancer Institute, Boston, Massachusetts 02215, USA.
authors.forename: Kwok-Kin
authors.initials: KK
authors.lastname: Wong
authors.affiliation: Lowe Center for Thoracic Oncology, Dana-Farber Cancer Institute, Boston, Massachusetts 02215, USA.|Belfer Center for Applied Cancer Science, Dana-Farber Cancer Institute, Boston, Massachusetts 02215, USA.
authors.forename: Pasi A
authors.initials: PA
authors.lastname: Jänne
authors.affiliation: Department of Cancer Biology, Dana-Farber Cancer Institute, Boston, Massachusetts 02215, USA.|Department of Biological Chemistry and Molecular Pharmacology, Harvard Medical School, Boston, Massachusetts 02115, USA.
authors.forename: Michael J
authors.initials: MJ
authors.lastname: Eck
mesh_terms: D000494:Allosteric Regulation / Q000187:drug effects; D000495:Allosteric Site / Q000187:drug effects; D000818:Animals; D000970:Antineoplastic Agents / Q000494:pharmacology*; D044482:Benzeneacetamides / Q000494:pharmacology*; D002289:Carcinoma, Non-Small-Cell Lung / Q000188:drug therapy / Q000201:enzymology / Q000473:pathology; D045744:Cell Line, Tumor; D049109:Cell Proliferation / Q000187:drug effects; D000068818:Cetuximab / Q000494:pharmacology; D004195:Disease Models, Animal; D018432:Drug Resistance, Multiple / Q000187:drug effects / Q000235:genetics; D019008:Drug Resistance, Neoplasm / Q000187:drug effects / Q000235:genetics*; D004357:Drug Synergism; D066246:ErbB Receptors / Q000037:antagonists & inhibitors / Q000737:chemistry / Q000235:genetics* / Q000378:metabolism; D008175:Lung Neoplasms / Q000188:drug therapy / Q000201:enzymology / Q000473:pathology; D051379:Mice; D050505:Mutant Proteins / Q000037:antagonists & inhibitors* / Q000737:chemistry / Q000235:genetics / Q000378:metabolism; D011487:Protein Conformation / Q000187:drug effects; D047428:Protein Kinase Inhibitors / Q000494:pharmacology*; D055503:Protein Multimerization / Q000187:drug effects; D013844:Thiazoles / Q000494:pharmacology*
chemical_list: D000970:Antineoplastic Agents; D044482:Benzeneacetamides; C000608614:EAI045; D050505:Mutant Proteins; D047428:Protein Kinase Inhibitors; D013844:Thiazoles; C512478:EGFR protein, human; D066246:ErbB Receptors; D000068818:Cetuximab