CH7233163 Overcomes Osimertinib-Resistant EGFR-Del19/T790M/C797S Mutation.

Osimertinib is the only EGFR-tyrosine kinase inhibitor (TKI) capable of overcoming EGFR-T790M-mutated NSCLC, but osimertinib-resistant EGFR triple mutations (Del19/T790M/C797S or L858R/T790M/C797S) have been reported. Although allosteric EGFR TKIs (e.g., EAI-045) that potentially overcome L858R/T790M/C797S have been identified, there are no effective inhibitors against Del19/T790M/C797S. In this study, we identified CH7233163 as having the potential to overcome EGFR-Del19/T790M/C797S. CH7233163 showed potent antitumor activities against tumor with EGFR-Del19/T790M/C797S in vitro and in vivo In addition to EGFR-Del19/T790M/C797S, the characterization assays showed that CH7233163 more selectively inhibits various types of EGFR mutants (e.g., L858R/T790M/C797S, L858R/T790M, Del19/T790M, Del19, and L858R) over wild type. Furthermore, crystal structure analysis suggested that CH7233163 is a noncovalent ATP-competitive inhibitor for EGFR-Del19/T790M/C797S that utilizes multiple interactions with the EGFR's αC-helix-in conformation to achieve potent inhibitory activity and mutant selectivity. Therefore, we conclude that CH7233163 is a potentially effective therapy for osimertinib-resistant patients, especially in cases of EGFR-Del19/T790M/C797S.

Kashima K ，Kawauchi H ，Tanimura H ，Tachibana Y ，Chiba T ，Torizawa T ，Sakamoto H ... -  《-》

Interaction and molecular dynamics simulation study of Osimertinib (AstraZeneca 9291) anticancer drug with the EGFR kinase domain in native protein and mutated L844V and C797S.

Targeted therapy is a novel, promising approach to anticancer treatment that endeavors to overcome drug resistance to traditional chemotherapies. Patients with the L858R mutation in epidermal growth factor receptor (EGFR) respond to the first generation tyrosine kinase inhibitors (TKIs); however, after one year of treatment, they may become resistant. The T790M mutation is the most probable cause for drug resistance. Third generation drugs, including Osimertinib (AZD9291), are more effective against T790M and other sensitive mutations. Osimertinib is effective against the L844V mutation, has conditional effectiveness for the L718Q mutation, and is ineffective for the Cys797Ser (C797S) mutation. Cells that have both the T790M and C797 mutations are more resistant to third generation drugs. Although research has shown that Osimertinib is an effective treatment for EGFR L844V cells, this has not been shown for cells that have the C797S mutation. This molecular mechanism has not been well-studied. In the present study, we used the GROMACS software for molecular dynamics simulation to identify interactions between Osimertinib and the kinase part of EGFR in L844V and C797S mutants. We evaluated native EGFR protein and the L844V and C797S mutations' docking and binding energy, kI, intermolecular, internal, and torsional energy parameters. Osimertinib was effective for the EGFR L844V mutation, but not for EGFR C797S. All simulations were validated by root-mean-square deviation (RMSD), root-mean square fluctuation (RMSF), and radius of gyration (ROG). According to our computational simulation, the results supported the experimental models and, therefore, could confirm and predict the molecular mechanism of drug efficacy.

Assadollahi V ，Rashidieh B ，Alasvand M ，Abdolahi A ，Lopez JA ... -  《-》

HJM-561, a Potent, Selective, and Orally Bioavailable EGFR PROTAC that Overcomes Osimertinib-Resistant EGFR Triple Mutations.

The EGFR C797S mutation is the most common on-target resistance mechanism to osimertinib in patients with advanced non-small cell lung cancer (NSCLC). Currently there are no effective treatment options for patients with NSCLC harboring EGFR C797S triple mutants (Del19/T790M/C797S and L858R/T790M/C797S). Herein, we report an orally bioavailable EGFR PROTAC, HJM-561, which selectively degrades the EGFR C797S-containing triple mutants. HJM-561 potently inhibits the proliferation of Del19/T790M/C797S and L858R/T790M/C797S Ba/F3 cells while sparing cells expressing wild-type EGFR. Oral administration of HJM-561 shows robust antitumor activity in EGFR Del19/T790M/C797S-driven Ba/F3 CDX and PDX models that were resistant to osimertinib treatment. Taken together, our results suggest that HJM-561 is a promising therapeutic option for overcoming EGFR triple mutation-mediated drug resistance in NSCLC.

Du Y ，Chen Y ，Wang Y ，Chen J ，Lu X ，Zhang L ，Li Y ，Wang Z ，Ye G ，Zhang G ... -  《-》

Response to Brigatinib Targeted Therapy in Non-Small Cell Lung Cancer Harboring Epidermal Growth Factor Receptor Exon 19 Deletion, T790M, and cis-C797S Triple Mutations: A Case Report.

Chen ZW ，Lin G ，Shih HJ ，Wu CE ... -  《INTERNATIONAL JOURNAL OF MOLECULAR SCIENCES》

Design, Synthesis, and Biological Evaluation of Novel EGFR PROTACs Targeting C797S Mutation.

Zhu Y ，Ye X ，Wu Y ，Shen H ，Cai Z ，Xia F ，Min W ，Hou Y ，Wang L ，Wang X ，Xiao Y ，Yang P ... -  《-》