1P Real-world frequency of non-small cell lung cancer with epidermal growth factor receptor (EGFR) exon 20 insertion (Exon20ins) mutations by site of insertion

EGFR exon20 insertion mutations in non-small cell lung cancer: Clinical implications and recent advances in targeted therapies

The advent of targeted therapies for oncogenic mutations has led to a major paradigm shift in the management of non-small cell lung cancer (NSCLC). Molecular targets, such as epidermal growth factor receptor (EGFR)-activating mutations in the region of exons 18 through 21 are the most common oncogenic driver in NSCLC. Classical activating mutations, such as in-frame deletions in exon 19 and point mutations in exon 21 (L858R), are strong predictors for good clinical response to the approved EGFR-tyrosine kinase inhibitors (EGFR-TKIs). However, low frequency mutations occurring within exon 20 (ex20ins) have poorer responses to first/second generation EGFR-TKIs. Moreover, patients with NSCLC harboring EGFR ex20ins are known to have poorer prognosis than those with other EGFR-TKI sensitive mutations, leading to unmet clinical need of novel specific therapeutic options. Rapid changes in molecular diagnostics identifying specific causes have hastened the translation of diagnostic recommendations into clinical practice. Emergence of treatment strategies targeting EGFR ex20ins, such as newer EGFR-TKIs with increased specificity and novel approaches using bispecific monoclonal antibodies, may hold promising therapeutic options in the near future. In this review, we describe the structural, molecular characteristics, and detection strategies of EGFR ex20ins mutations and summarize the latest clinical data on approved treatments and emerging therapies for patients with NSCLC harboring EGFR ex20ins mutations. Further, we will discuss the response heterogeneity of ex20ins mutations to new drugs and acquired drug resistance mechanisms.

Optimizing diagnosis and treatment of EGFR exon 20 insertions mutant NSCLC

The Epidermal growth factor receptor (EGFR) exon (ex) 20 insertions (ins) has been considered as an "undruggable target" for a long time, with platinum-pemetrexed combination recommended as upfront standard treatment for newly diagnosed advanced non-small cell lung cancer (NSCLC) patients. Recent preliminary data from early phase clinical trials have demonstrated that pharmacological inhibition of EGFRex20ins is possible, offering new treatment opportunities to 1-2% of advanced NSCLC patients harboring such hard-to-treat molecular alteration. Among the different drugs under clinical investigation, both amivantamab and mobocertinib have received regulatory approval in the United States, by the Food and Drugs Administration (FDA), while amivantamab has been recently approved also in Europe, for the clinical treatment of advanced NSCLC patients harboring EGFRex20ins who failed at least one prior line of systemic therapy, representing a major breakthrough in lung cancer treatment over the last year. With novel effective targeted options on the horizon, there is a renewed interest on optimizing the molecular screening of advanced NSCLC, and next-generation sequencing (NGS)-based genotyping is currently considered the gold standard approach to profile advanced NSCLC patients, as recommended by international guidelines. Herein we provide an updated overview of the most recent findings and upcoming challenges regarding both molecular detection and therapeutic management of EGFR ex20ins mutant advanced NSCLC patients.

[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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