BDTX-189, a novel tyrosine kinase inhibitor, inhibits cell activity via ERK and AKT pathways in the EGFR C797S triple mutant cells

The tertiary mutation C797S in the structural domain of the EGFR kinase is a common cause of resistance to third-generation EGFR tyrosine kinase inhibitors (TKIs). In this study, we used a potent, selective and irreversible inhibitor, BDTX-189, to target EGFR C797S triple mutant cells for cell activity. The study constructed the H1975-C797S (EGFR L858R/T790 M/C797S) cell line using the CRISPR/Cas9 method and investigated its potential as a fourth-generation tyrosine kinase inhibitor via chemosensitivity approach. The results demonstrated its ability to induce cytotoxic effects, and inhibit EGFR L858R/T790 M/C797S cell growth and proliferation in a dose-dependent manner. Meanwhile, BDTX-189 reduces the protein phosphorylation levels of EGFR, ERK, and AKT, promoting apoptosis. Furthermore, BDTX-189 not only inhibits common EGFR triple mutations but also effectively inhibits EGFR L858R mutation and EGFR L858R/T790 M mutation. These findings support the cytotoxic effect of BDTX-189 and its inhibitory effect on cell division and proliferation with the EGFR C797S triple mutation.

HER2 in Non-Small Cell Lung Cancer: A Review of Emerging Therapies

Simple Summary

There are growing data on targeting HER2 alterations, which include gene mutations, gene amplifications, and protein overexpression, for non-small cell lung cancer (NSCLC). Currently, there are limited targeted therapies approved for NSCLC patients with HER2 alterations, and this remains an unmet clinical need. There has been an influx of research on antibody–drug conjugates, monoclonal antibodies, and tyrosine kinase inhibitors. This review discusses the diagnostic challenges of HER2 alterations in NSCLC and summarizes recent progress in HER2 targeted drugs for both clinicians and researchers treating this patient population.

Abstract

Human epidermal growth factor receptor 2 (HER2), a member of the ERBB family of tyrosine kinase receptors, has emerged as a therapeutic target of interest for non-small cell lung cancer (NSCLC) in recent years. Activating HER2 alterations in NSCLC include gene mutations, gene amplifications, and protein overexpression. In particular, the HER2 exon 20 mutation is now a well clinically validated biomarker. Currently, there are limited targeted therapies approved for NSCLC patients with HER2 alterations. This remains an unmet clinical need, as HER2 alterations are present in 7–27% of de novo NSCLC and may serve as a resistance mechanism in up to 10% of EGFR mutated NSCLC. There has been an influx of research on antibody–drug conjugates (ADCs), monoclonal antibodies, and tyrosine kinase inhibitors (TKIs) with mixed results. The most promising therapies are ADCs (trastuzumab-deruxtecan) and novel TKIs targeting exon 20 mutations (poziotinib, mobocertinib and pyrotinib); both have resulted in meaningful anti-tumor efficacy in HER2 mutated NSCLC. Future studies on HER2 targeted therapy will need to define the specific HER2 alteration to better select patients who will benefit, particularly for HER2 amplification and overexpression. Given the variety of HER2 targeted drugs, sequencing of these agents and optimizing combination therapies will depend on more mature efficacy data from clinical trials and toxicity profiles. This review highlights the challenges of diagnosing HER2 alterations, summarizes recent progress in novel HER2-targeted agents, and projects next steps in advancing treatment for the thousands of patients with HER2 altered NSCLC.

[Advances in Treatment of Non-small Cell Lung Cancer Harboring EGFR Exon 20 Insertion Mutations]

Epidermal growth factor receptor (EGFR) exon 20 insertion mutations are the third most prevalent activating EGFR mutation in non-small cell lung cancer (NSCLC), accounting for 5%-12% of all EGFR mutations in NSCLC cases. Patients harboring EGFR exon 20 insertion mutations exhibit similar clinical characteristics except for worse prognosis as compared to those with 'classic' EGFR mutations. EGFR exon 20 insertion mutations are considered as a heterogeneous class of alterations that cause different conformational changes in EGFR. The majority of mutations (almost 90% of cases) is positioned in the loop that immediately follows the C-terminal of the C-helix, and the most widely reported subtype of insertion mutations is D770_N771>ASVDN(A767_V769dupASV) with frequency of 21%-28%. NSCLC patients with EGFR exon 20 insertion mutations show primary drug resistance to previously approved EGFR tyrosine kinase inhibitors and are generally insensitive to conventional chemotherapy and immunotherapy. The recently approved targeted drugs Amivantamab and Mobocertinib shift the treatment paradigm for NSCLC patients harboring EGFR exon 20 insertion mutations. There are also several new compounds targeting NSCLC EGFR exon 20 insertion mutations are in development. In this article, we provide a through overview on the treatment development in EGFR exon 20 insertion mutant NSCLC.
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