Resistance mechanisms to osimertinib and emerging therapeutic strategies in nonsmall cell lung cancer

Shenqifuzheng injection inhibits lactic acid-induced cisplatin resistance in NSCLC by affecting FBXO22/p53 axis through FOXO3

BACKGROUND

Non-small cell lung cancer (NSCLC) accounts for 80% of lung cancers. Cisplatin (DDP)-based combination chemotherapy is the main treatment of NSCLC. Due to resistance to DDP, 5-year overall survival rate of NSCLC patients is very low. Shenqifuzheng injection (SQFZ) is essential for lung cancer progression. However, whether SQFZ plays a role in DDP resistance in NSCLC and its molecular mechanism remains unclear.

METHODS

Levels of FOXO3, FBXO22 and p53 in NSCLC tissues and cells were assessed by RT-qPCR and Western blot. Cell proliferation and apoptosis were analyzed utilizing CCK-8, Colony formation and Flow cytometry assays. Lactate (LA) levels were tested via ELISA. ChIP and Dual luciferase reporter assays validated regulatory relationship between FOXO3 and FBXO22. Immunoprecipitation assay evaluated p53 ubiquitination levels. The subcutaneous tumor model of nude mice was constructed. TUNEL staining detected apoptosis in tissues, and IHC assessed expression of Ki67, FOXO3, FBXO22 and p53.

RESULTS

FOXO3 was decreased, whereas LA and FBXO22 were increased in NSCLC patients. LA led to a higher DDP resistance in A549/DDP cells, while SQFZ reversed this effect by upregulating FOXO3. Furthermore, FBXO22 was a downstream effecter of FOXO3 and FBXO22 affected p53 ubiquitination to reverse the inhibitory effect of SQFZ. We next found SQFZ inhibited LA-induced DDP resistance in NSCLC via FOXO3/FBXO22/p53 axis. Finally, SQFZ regulated LA-mediated DDP resistance in NSCLC nude mice.

CONCLUSION

SQFZ influences LA-induced DDP resistance in NSCLC via FOXO3/FBXO22/p53 pathway, providing a promising agent for NSCLC treatment.

Evaluation of the prognostic value of the new 9th edition Tumor-Node-Metastases (TNM) staging system for epidermal growth factor receptor (EGFR)-mutated lung adenocarcinoma patients with bone metastases

BACKGROUND

There are some changes in the new 9th edition Tumor-Node-Metastases (TNM) staging system for lung cancer, including subdividing M1c into M1c1 and M1c2 stage. The aim of this study was to assess the prognostic performance of the updated classification system and try to provide some real-world application data among advanced lung adenocarcinoma patients with bone metastases.

METHODS

Advanced lung adenocarcinoma patients in M1c stage with bone metastases who receiving first-line first-generation epidermal growth factor receptor tyrosine kinase inhibitor (EGFR-TKI) and T790M-guided osimertinib as the second-line therapy were retrospectively screened from December 2016 to December 2021. A total of 126 patients were enrolled in this study. 62 patients and 64 patients were subdivided into M1c1 and M1c2 groups according to the 9th edition of TNM staging system.The first-line real-world progression-free survival (1LrwPFS), the second-line real-world progression-free survival (2LrwPFS), post-progression survival (PPS) and real-world overall survival (rwOS) were analyzed.

RESULTS

The overall median rwOS was 40.1 months (95% CI 35.996-44.204). 1LrwPFS was 13.9 months (95% CI 12.653-15.147) and 2LrwPFS was 14.5 months (95% CI 11.665-17.335) for all patients.Patients in M1c2 stage was inferior to M1c1 stage patients in rwOS (35.2 months vs. 42.9 months, HR = 0.512, P = 0.005). 2LrwPFS was moderately correlated with rwOS (r = 0.621, R2 = 0.568, P = 0.000). Multivariate analysis showed performance status (PS) score ≥ 2 and TP53 alteration positive were independent prognostic factors of worse rwOS.

CONCLUSIONS

More refined stratification of M1c according to the 9th edition of TNM staging system is conducive to the judgment of prognosis and the implementation of precision medicine for patients.

Targeting EGFR with molecular degraders as a promising strategy to overcome resistance to EGFR inhibitors

Abnormal activation of EGFR is often associated with various malignant tumors, making it an important target for antitumor therapy. However, traditional targeted inhibitors have several limitations, such as drug resistance and side effects. Many studies have focused on the development of EGFR degraders to overcome this resistance and enhance the therapeutic effect on tumors. Proteolysis targeting chimeras (PROTAC) and Lysosome-based degradation techniques have made significant progress in degrading EGFR. This review provides a summary of the structural and function of EGFR, the resistance, particularly the research progress and activity of EGFR degraders via the proteasome and lysosome. Furthermore, this review aims to provide insights for the development of the novel EGFR degraders.

Exploring the structural activity relationship of the Osimertinib: A covalent inhibitor of double mutant EGFRL858R/T790M tyrosine kinase for the treatment of Non-Small Cell Lung Cancer (NSCLC)

The USFDA granted regular approval to Osimertinib (AZD9291) on March 2017, for treating individuals with metastatic Non-Small Cell Lung Cancer having EGFR T790M mutation. Clinically, Osimertinib stands at the forefront for the treatment of patients with Non-Small Cell Lung Cancer. Osimertinib forms a covalent bond with the Cys797 residue and predominantly spares binding to WT-EGFR, thereby reducing toxicity and enabling the administration of doses that effectively inhibit T790M. However, a high percentage of patients treated with Osimertinib (AZD9291) developed a tertiary cysteine797 to serine797 (C797S) mutation in the EGFR kinase domain, rendering resistance to it. This comprehensive review sheds light on the chemistry, computational aspects, structural features, and expansive spectrum of biological activities of Osimertinib and its analogues. The in-depth exploration of these facets serves as a valuable resource for medicinal chemists, empowering them to design better Osimertinib analogues. This exhaustive study not only provides insights into improving potency but also emphasizes considerations for mutant selectivity and optimizing pharmacokinetic properties. This review acts as a guiding beacon for the strategic design and development of next-generation Osimertinib analogues.

Characterization of Patients with EGFR Mutation-Positive NSCLC Following Emergence of the Osimertinib Resistance Mutations, L718Q or G724S: A Multicenter Retrospective Observational Study in France

Purpose

The third-generation epidermal growth factor receptor (EGFR) tyrosine kinase inhibitor (TKI), osimertinib, is an effective first-line therapy for patients with common EGFR mutation-positive non-small cell lung cancer (NSCLC). However, almost all patients become resistant to treatment. In some patients, emergence of tertiary EGFR mutations is implicated as a resistance mechanism. This study describes patients with NSCLC who acquired the rare EGFR mutations, L718Q or G724S, following EGFR TKI treatment.

Patients and Methods

This was a retrospective, observational study undertaken in France from Feb-Nov 2021, in patients with EGFR mutation-positive NSCLC with an acquired L718Q or G724S mutation. Primary objectives were description of tumor characteristics, progression, and progression under treatment.

Results

Nine eligible patients were identified. Acquired resistance to initial EGFR TKI treatment was associated with T790M emergence in six patients, who then received osimertinib monotherapy. Overall, eight patients received osimertinib monotherapy treatment at some point (average treatment duration: 18.3 months). Following the emergence of L718Q or G724S, patients received chemotherapy (n = 4; two of whom subsequently received afatinib), nivolumab (n = 2), afatinib (n = 2), or immunochemotherapy (n = 1). In the four patients who received afatinib after identification of L718Q or G724S, 2 achieved a partial response, one had stable disease and one had progressive disease. Treatment duration was 1.6-31.7 months. In patients with controlled disease (n = 3), progression-free survival was 6.1-31.7 months. Two of these patients had previously received osimertinib.

Conclusion

Currently, there is no consensus regarding the treatment of EGFR mutation-positive NSCLC following emergence of the osimertinib resistance mutations, L718Q or G724S. Afatinib appears to be a promising treatment option in this setting.

Marine-derived EGFR inhibitors: novel compounds targeting breast cancer growth and drug resistance

Breast cancer (BC) continues to be a major health challenge globally, ranking as the fifth leading cause of cancer mortality among women, despite advancements in cancer detection and treatment. In this study, we identified four novel compounds from marine organisms that effectively target and inhibit the Epidermal Growth Factor Receptor (EGFR), crucial for BC cell growth and proliferation. These compounds not only induced early apoptosis through Caspase-3 activation but also showed significant inhibitory effects on EGFR mutations associated with drug resistance (T790M, L858R, and L858R/T790M), demonstrating high EGFR kinase selectivity. Cell Thermal Shift Assay (CETSA) experiments indicated that Tandyukisin stabilizes EGFR in a concentration-dependent manner. Furthermore, binding competition assays using surface plasmon resonance technology revealed that Tandyukisin and Trichoharzin bound to distinct sites on EGFR and that their combined use enhanced apoptosis in BC cells. This discovery may pave the way for developing new marine-derived EGFR inhibitors, offering a promising avenue for innovative cancer treatment strategies and addressing EGFR-mediated drug resistance.

Prognostic and predictive biomarkers with therapeutic targets in nonsmall-cell lung cancer: A 2023 update on current development, evidence, and recommendation

BACKGROUND

Since the publication of the original work in 2014, significant progress has been made in the characterization of genomic alterations that drive oncogenic addiction of nonsmall cell lung cancer (NSCLC) and how the immune system can leverage non-oncogenic pathways to modulate therapeutic outcomes. This update evaluates and validates the recent and emerging data for prognostic and predictive biomarkers with therapeutic targets in NSCLC.

DATA SOURCES

We performed a literature search from January 2015 to October 2023 using the keywords non-small cell lung cancer, clinical practice guidelines, gene mutations, genomic assay, immune cancer therapy, circulating tumor DNA, predictive and prognostic biomarkers, and targeted therapies.

STUDY SELECTION AND DATA EXTRACTION

We identified, reviewed, and evaluated relevant clinical trials, meta-analyses, seminal articles, and published clinical practice guidelines in the English language.

DATA SYNTHESIS

Regulatory-approved targeted therapies include those somatic gene alterations of EGFR ("classic" mutations, exon 20 insertion, and rare EGFR mutations), ALK, ROS1, BRAF V600, RET, MET, NTRK, HER2, and KRAS G12C. Data for immunotherapy and circulating tumor DNA in next-generation sequencing are considered emerging, whereas the predictive role for PIK3CA gene mutation is insufficient.

CONCLUSIONS

Advances in sequencing and other genomic technologies have led to identifying novel oncogenic drivers, novel resistance mechanisms, and co-occurring mutations that characterize NSCLC, creating further therapeutic opportunities. The benefits associated with immunotherapy in the perioperative setting hold initial promise, with their long-term results awaiting.

Genetic mutation profiling reveals biomarkers for targeted therapy efficacy and prognosis in non-small cell lung cancer

Introduction

The genetic heterogeneity of non-small cell lung cancer (NSCLC) with epidermal growth factor receptor (EGFR) mutations may affect clinical responses and outcomes to EGFR tyrosine kinase inhibitors (EGFR-TKIs). This study aims to investigate the genomic factors that influence the efficacy and clinical outcomes of first-line, second-line and third-line treatments in NSCLC and explore the heterogeneity of resistance mechanisms.

Materials and methods

This real-world study comprised 65 patients with EGFR mutant NSCLC. Molecular alterations were detected using a customized DNA panel before and after administering targeted therapy. The efficacy and prognosis of each treatment line were evaluated.

Results

In first-generation EGFR-TKIs treatment, gefitinib showed favorable efficacy compared to icotinib and erlotinib, particularly in patients with EGFR L858R mutations. The resistance mechanisms to first-generation EGFR-TKIs varied among different EGFR mutation cohorts and different first-generation EGFR-TKIs. In second-line EGFR-TKIs treatment, EPH receptor A3 (EPHA3), IKAROS family zinc finger 1 (IKZF1), p21 (RAC1) activated kinase 5 (PAK5), DNA polymerase epsilon, catalytic subunit (POLE), RAD21 cohesin complex component (RAD21) and RNA binding motif protein 10 (RBM10) mutations were markedly associated with poorer progression-free survival (PFS). Notably, EPHA3, IKZF1 and RBM10 were identified as independent predictors of PFS. The mechanisms of osimertinib resistance exhibited heterogeneity, with a higher proportion of non-EGFR-dependent resistant mutations. In third-line treatments, the combination of osimertinib and anlotinib demonstrated superior efficacy compared to other regimens. Glutamate ionotropic receptor NMDA type subunit 2A (GRIN2A) mutation was an independent risk indicator of shorter OS following third-line treatments.

Conclusions

Comprehending the tumor evolution in NSCLC is advantageous for assessing the efficacy and prognosis at each stage of treatment, providing valuable insights to guide personalized treatment decisions for patients.

Mechanisms analysis for Formononetin counteracted-Osimertinib resistance in non-small cell lung cancer cells: From the insight into the gene transcriptional level

Formononetin is one of the main isoflavone components, which has strong anti-cancer effects in non-small cell lung cancer (NSCLC). However, the potentials and the mechanisms of Formononetin to counteract the Osimertinib resistance in NSCLC are unclear. In this study, Formononetin-induced cell apoptosis, cell proliferation, and clonal formation were detected in Osimertinib-resistant NSCLC cells (H1975_OR). RNA sequencing analysis was conducted to study the gene expression profiles of Formononetin-induced H1975_OR cells. The results indicated that Formononetin could significantly induce cell apoptosis, whereas dramatically inhibited cell proliferation and clonal formation on H1975_OR cells. Furthermore, a total of 4309 differentially expressed genes (DEGs) between Formononetin-treated and nontreated H1975_OR cells were had been detected. Gene Ontology (GO) annotation enrichment analysis, Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway enrichment analysis and the Gene Set Enrichment Analysis (GSEA) showed that Formononetin affected the expression of genes involving in anatomical structure morphogenesis, anatomical structure development, and multicellular organism development via regulating inflammation- and metabolism-related signaling pathways. Taken together, our study preliminarily revealed the mechanisms of Formononetin to counteract the Osimertinib resistance in NSCLC cells from the transcriptional level and provided a potential treatment method for Osimertinib-resistant NSCLC patients.

Comprehensive genomic profiling of Japanese patients with thoracic malignancies: A single-center retrospective study

BACKGROUND

Few studies have been conducted on comprehensive genomic profiling (CGP) panels in Japanese patients with thoracic malignancies after completing standard treatment. Consequently, its value in clinical practice remains unclear.

METHODS

We conducted a retrospective study of Japanese patients with thoracic malignancies who underwent CGP between June 2019 and November 2022 at our hospital. We evaluated the detection rate of actionable genetic alterations and percentage of patients who received genomically-matched therapy. Furthermore, we examined the value of the CGP panel in patients who underwent multiplex gene-panel testing prior to their initial treatment. This study was performed in accordance with the principles of the Declaration of Helsinki.

RESULTS

The study included 56 patients, of whom 47 (83.9%) had actionable genetic alterations and 8 (14.3%) received genomically-matched therapy. Of these, four patients were treated with approved drugs and three patients were treated with investigational agents. In addition, one patient was treated with approved drugs using the patient-directed care system. Of the 17 patients who had multiplex gene-panel testing performed at the start of their initial therapy, two (11.8%) were newly identified by the CGP panel and subsequently received genomically-matched therapy. EGFR L718Q and MET amplification were observed in two of the seven patients with epidermal growth factor receptor-tyrosine kinase inhibitor resistance.

CONCLUSIONS

The CGP panel could identify genetic alterations, thereby facilitating genomically-matched therapy, even in patients with thoracic malignancies who could not be identified using multiplex gene-panel testing.

Full spectrum flow cytometry-powered comprehensive analysis of PBMC as biomarkers for immunotherapy in NSCLC with EGFR-TKI resistance

BACKGROUND

Clinical studies suggest that immune checkpoint inhibitor (ICI) monotherapy has limited benefits in non-small cell lung cancer (NSCLC) patients after epidermal growth factor receptor-tyrosine kinase inhibitor (EGFR-TKI) failure. However, data about efficacy of ICI plus chemotherapy remain controversial, probably attributed to the heterogeneity among such population, and robust efficacy biomarkers are urgent to explore.

METHODS

A total of 60 eligible patients who received ICI plus chemotherapy after EGFR-TKI treatment failure were enrolled, 24 of whom peripheral blood mononuclear cell (PBMC) samples were collected at baseline and after 2 cycles of treatment. We have designed a 23-color-antibody panel to detect PBMC by full spectrum flow cytometry.

RESULTS

For EGFR-TKI resistant NSCLC patients: 1) ICI plus chemotherapy achieved an objective response rate (ORR) of 21.7% and a median progression-free survival (PFS) of 6.4 months. 2) clinical characteristics associated with worse efficacy included liver metastasis and platelet-to-lymphocyte ratio (PLR) > 200. 3) the proportion of immune cell subset associated with better efficacy was higher baseline effective CD4⁺T cells (E4). 4) the baseline expression of immune checkpoint proteins (ICPs) on cell subsets associated with better efficacy included: higher expression of CD25 on dendritic cells (DC) and central memory CD8⁺T cells (CM8), and higher expression of Lymphocyte activation gene 3 (LAG-3) on effective memory CD8⁺T cells (EM8). 5) the expression of ICPs after 2 cycles of treatment associated with better efficacy included: higher expression of CD25 on CD8⁺T/EM8 /natural killer (NK) cells. 6) the dynamic changes of ICPs expression associated with worse efficacy included: significantly decrease of T cell immunoglobulin and ITIM domain (TIGIT) expression on regular T cells (Tregs) and decrease of V-domain immunoglobulin suppressor of T cell activation (VISTA) expression on Th1. 7) a prediction model for the efficacy of ICI plus chemotherapy was successfully constructed with a sensitivity of 62.5%, specificity of 100%, and area under curve (AUC) = 0.817.

CONCLUSIONS

Some EGFR-TKI-resistant NSCLC patients could indeed benefit from ICI plus chemotherapy, but most patients are primary resistant to immunotherapy. Comprehensive analysis of peripheral immune cells using full spectrum flow cytometry showed that compared to the proportion of cell subsets, the expression type and level of ICPs on immune cells, especially CD25, were significantly correlated with the efficacy of immunotherapy.

EGFR and ERBB2 exon 20 insertion/duplication in advanced non-small cell lung cancer: genomic profiling and clinicopathologic features

Background

Exon 20 (ex20) in-frame insertions or duplications (ins/dup) in epidermal growth factor receptor (EGFR) and its analog erb-b2 receptor tyrosine kinase 2 (ERBB2) are each detected in 1.5% of non-small cell lung cancer (NSCLC). Unlike EGFR p.L858R or ex19 deletions, ex20 ins/dup is associated with de novo resistance to classic EGFR inhibitors, lack of response to immune checkpoint inhibitors, and poor prognosis. US Food and Drug Administration has approved mobocertinib and amivantamab for targeting tumors with this aberration, but the number of comprehensive studies on ex20 ins/dup NSCLC is limited. We identified 18 cases of NSCLCs with EGFR/ERBB2 ex20 ins/dup and correlated the findings with clinical and morphologic information including programed death-ligand 1 (PD-L1) expression.

Methods

A total of 536 NSCLC cases tested at our institution between 2014 and 2023 were reviewed. A custom-designed 214-gene next-generation sequencing panel was used for detecting DNA variants, and the FusionPlex CTL panel (ArcherDx) was used for the detection of fusion transcripts from formalin-fixed, paraffin-embedded tissue. Immunohistochemistry (IHC)for PD-L1 was performed using 22C3 or E1L3N clones.

Results

Nine EGFR and nine ERBB2 ex20 ins/dup variants were identified from an equal number of men and women, 14 were non- or light smokers, and 15 had stage IV disease. All 18 cases were adenocarcinomas. Seven of the 11 cases with available primary tumors had acinar predominant pattern, two had lepidic predominant pattern, and the remainder had papillary (one case) and mucinous (one case) patterns. Ex20 ins/dup variants were heterogenous in-frame one to four amino acids spanning A767-V774 in EGFR and Y772-P780 in ERBB2 and were clustered in the loop following the C-helix and α C-helix. Twelve cases (67%) had co-existing TP53 variants. Copy number variation in CDK4 amplification was identified in one case. No fusion or microsatellite instability was identified in any case. PD-L1 was positive in two cases, low positive in four cases, and negative in 11 cases.

Conclusions

NSCLCs harboring EGFR/ERBB2 ex20 ins/dup are rare and tend to be acinar predominant, negative for PD-L1, more frequent in non- or light smokers, and mutually exclusive with other driver mutations in NSCLC. The correlation of different EGFR/ERBB2 ex20 ins/dup variants and co-existing mutations with response to targeted therapy and the possibility of developing resistant mutations after mobocertinib treatment warrants further investigation.

Proteolysis targeting chimeras in non-small cell lung cancer

Non-small cell lung cancer (NSCLC) has very poor prognosis in advanced stages. Discovery and application of therapies targeting specific oncogenic driver mutations has greatly improved overall survival. However, targeted therapies are limited in their efficacy due to resistance mutations that may arise with long term use. Proteolysis targeting Chimeras (PROTACs) are a promising approach to combating resistance mutations. PROTACs commandeer innate ubiquitination machinery to degrade oncogenic proteins. Here we review the PROTACs that have been developed for targeting common EGFR, KRAS, and ALK mutations.

Making the Best Use of Available Weapons for the Inevitable Rivalry-Resistance to EGFR-TKIs

The emergence of epidermal growth factor receptor-tyrosine kinase inhibitors (EGFR-TKIs) revolutionized the treatment of advanced-stage non-small cell lung cancer (NSCLC). Detected in more than 50% of late-stage lung adenocarcinoma in Asian patients, the EGFR mutation was regarded as a golden mutation for Asians. However, resistance to TKIs seems inevitable and severely hinders patients from getting further benefits from treatment. Even though resistance caused by EGFR T790M could be effectively managed by third-generation EGFR-TKIs currently, resistance to third-generation EGFR-TKIs is still a troublesome issue faced by both clinicians and patients. Various efforts have been made to maximize the benefits of patients from EGFR-TKIs therapy. Thus, new requirements and challenges have been posed to clinicians of this era. In this review, we summarized the clinical evidence on the efficacy of third-generation EGFR-TKIs in patients with EGFR-mutated NSCLC. Then, we discussed advancements in sequential treatment aiming to delay the onset of resistance. Moreover, the resistance mechanisms and features were depicted to help us better understand our enemies. Lastly, we put forward future strategies, including recent approaches involving the utilization of antibody drug conjugates against resistance and research directions about shaping the evolution of NSCLC as a core idea in the management of NSCLC.

Intracranial efficacy and safety of furmonertinib 160 mg with or without anti-angiogenic agent in advanced NSCLC patients with BM/LM as salvage therapy

OBJECTIVES

Central nervous system (CNS) metastases including brain metastases (BM) and leptomeningeal metastases (LM) are frequent in epidermal growth factor receptor (EGFR)-mutated non-small cell lung cancer (NSCLC), and are correlated with poor outcomes. In this study, we evaluated the efficacy of single-agent furmonertinib 160 mg or combining with anti-angiogenic agent in NSCLC patients who had developed BM/LM progression from previous tyrosine kinase inhibior (TKI) treatment.

METHODS

EGFR-mutated NSCLC patients who developed BM (the BM cohort) or LM progression (the LM cohort) were included, having received furmonertinib 160 mg daily as second-line or later treatment, with or without anti-angiogenic agents. The intracranial efficacy was evaluated by intracranial progression-free survival (iPFS).

RESULTS

Totally 12 patients in the BM cohort and 16 patients in the LM cohort were included. Almost one half of patients in the BM cohort and a majority in the LM cohort had a poor physical status, with a Eastern Cooperative Oncology Group performance status (ECOG-PS) ≥2. The administration of single-agent furmonertinib or combination treatment achieved a median iPFS of 3.6 months (95%CI 1.435-5.705) in the BM cohort, and 4.3 months (95%CI 2.094-6.486) in the LM cohort. Subgroup and univariate analysis has shown that a good ECOG-PS correlated with a favorable efficacy of furmonertinib in the BM cohort (median iPFS = 2.1 with ECOG-PS ≥ 2 vs. 14.6 months with ECOG-PS < 2, P < 0.05). Overall, any grade of adverse events (AEs) occured in 46.4% of patients (13/28). Among them, 14.3% of patients (4 of 28) had grade 3 or higher AEs, and were all under control, led to no dose reductions or suspension.

CONCLUSION

Single-agent furmonertinib 160 mg or in combination of anti-angiogenic agent is an optional salvage therapy for advanced NSCLC patients who developed BM/LM progression from prior EGFR-TKI treatment, with a promising efficacy and an acceptable safety profile, and is worth of further exploration.

Can Liquid Biopsy Based on ctDNA/cfDNA Replace Tissue Biopsy for the Precision Treatment of EGFR-Mutated NSCLC?

More and more clinical trials have explored the role of liquid biopsy in the diagnosis and treatment of EGFR-mutated NSCLC. In certain circumstances, liquid biopsy has unique advantages and offers a new way to detect therapeutic targets, analyze drug resistance mechanisms in advanced patients, and monitor MRD in patients with operable NSCLC. Although its potential cannot be ignored, more evidence is needed to support the transition from the research stage to clinical application. We reviewed the latest progress in research on the efficacy and resistance mechanisms of targeted therapy for advanced NSCLC patients with plasma ctDNA EGFR mutation and the evaluation of MRD based on ctDNA detection in perioperative and follow-up monitoring.

Acquired Concurrent EGFR T790M and Driver Gene Resistance From EGFR-TKIs Hampered Osimertinib Efficacy in Advanced Lung Adenocarcinoma: Case Reports

The acquired resistance of epidermal growth factor receptor tyrosine kinase inhibitors (EGFR-TKIs) is inevitable and heterogeneous. The strategies to overcome acquired resistance are significant. For patients with secondary T790M-positive after early generation EGFR-TKIs, osimertinib is the standard second-line therapy. In patients resistant to prior early generation EGFR-TKIs, the acquired T790M mutation overlaps with other driver gene resistance, such as HER2-and MET amplification, accounting for 4–8%. The efficacy of osimertinib is unclear in patients with concurrent multiple driver gene resistance. We here report a patient who acquired EGFR T790M, STRN-ALK fusion, and EGFR amplification after gefitinib progression and subsequent MET amplification acquired from osimertinib. The other patient acquired EGFR T790M and MET amplification post-dacomitinib and acquired CCDC6-RET fusion after osimertinib treatment. Besides, subsequent new bypass activations were the possible resistance mechanisms to second-line osimertinib. Both patients had progression-free survival (PFS) less than 4 months and limited benefits from osimertinib second-line therapy. The T790M accompanying driver gene resistance will be a new subtype after EGFR-TKIs progression, needing effective treatment options.