Impact of T790M Mutation Status on Later-Line Osimertinib Treatment in Non-Small Cell Lung Cancer Patients

Molecular mechanisms and therapeutic strategies in overcoming chemotherapy resistance in cancer

Cancer remains a leading cause of mortality globally and a major health burden, with chemotherapy often serving as the primary therapeutic option for patients with advanced-stage disease, partially compensating for the limitations of non-curative treatments. However, the emergence of chemotherapy resistance significantly limits its efficacy, posing a major clinical challenge. Moreover, heterogeneity of resistance mechanisms across cancer types complicates the development of universally effective diagnostic and therapeutic approaches. Understanding the molecular mechanisms of chemoresistance and identifying strategies to overcome it are current research focal points. This review provides a comprehensive analysis of the key molecular mechanisms underlying chemotherapy resistance, including drug efflux, enhanced DNA damage repair (DDR), apoptosis evasion, epigenetic modifications, altered intracellular drug metabolism, and the role of cancer stem cells (CSCs). We also examine specific causes of resistance in major cancer types and highlight various molecular targets involved in resistance. Finally, we discuss current strategies aiming at overcoming chemotherapy resistance, such as combination therapies, targeted treatments, and novel drug delivery systems, while proposing future directions for research in this evolving field. By addressing these molecular barriers, this review lays a foundation for the development of more effective cancer therapies aimed at mitigating chemotherapy resistance.

Strategies and influencing factors for the treatment of advanced non-small cell lung cancer based on epidermal growth factor receptor tyrosine kinase inhibitors: a narrative review

Background and Objective

Epidermal growth factor receptor tyrosine kinase inhibitors (EGFR-TKIs) are the primary treatment for advanced non-small cell lung cancer (NSCLC) patients with EGFR mutations, significantly enhancing patient prognosis. Despite the efficacy of EGFR-TKIs, monotherapy faces challenges such as variability among individuals and early drug resistance. This article aims to explore the treatment strategies and influencing factors for advanced NSCLC patients treated with EGFR-TKIs, optimize treatment plans, and improve the prognosis of patients with advanced NSCLC.

Methods

We undertook a comprehensive, narrative review of the latest literature to define the current application and progress of EGFR-TKIs in treating patients with advanced NSCLC.

Key Content and Findings

The efficacy and promise of EGFR-TKIs, both as monotherapy and combined with other agents, for treating patients with advanced NSCLC are outlined. The study delves into the mechanisms of resistance and the ongoing development of EGFR-TKIs. Various factors influencing the treatment of advanced NSCLC patients with EGFR-TKIs are also examined.

Conclusions

EGFR-TKIs alone improve survival in patients with advanced NSCLC. Combined with other agents, some regimens have shown improved benefits in overcoming drug resistance and prolonging patient survival. It is imperative to focus on developing novel EGFR-TKIs and investigate innovative combination therapies to maximize patient benefit.

Liquid biopsy for the management of NSCLC patients under osimertinib treatment

Therapeutic management of NSCLC patients is quite challenging as they are mainly diagnosed at a late stage of disease, and they present a high heterogeneous molecular profile. Osimertinib changed the paradigm shift in treatment of EGFR mutant NSCLC patients achieving significantly better clinical outcomes. To date, osimertinib is successfully administered not only as first- or second-line treatment, but also as adjuvant treatment while its efficacy is currently investigated during neoadjuvant treatment or in stage III, unresectable EGFR mutant NSCLC patients. However, resistance to osimertinib may occur due to clonal evolution, under the pressure of the targeted therapy. The utilization of liquid biopsy as a minimally invasive tool provides insight into molecular heterogeneity of tumor clonal evolution and potent resistance mechanisms which may help to develop more suitable therapeutic approaches. Longitudinal monitoring of NSCLC patients through ctDNA or CTC analysis could reveal valuable information about clinical outcomes during osimertinib treatment. Therefore, several guidelines suggest that liquid biopsy in addition to tissue biopsy should be considered as a standard of care in the advanced NSCLC setting. This practice could significantly increase the number of NSCLC patients that will eventually benefit from targeted therapies, such as EGFR TKIs.

Effectiveness and safety of afatinib, gefitinib, and erlotinib for treatment-naïve elderly patients with epidermal growth factor receptor-mutated advanced non-small-cell lung cancer: a multi-institute retrospective study

BACKGROUND

In real-world practice, most patients with lung cancer are diagnosed when they are aged ≥65 years. However, clinical trials tend to lack data for the elderly population. Therefore, we aimed to describe the effectiveness and safety of afatinib, gefitinib, and erlotinib for elderly patients with epidermal growth factor receptor (EGFR)-mutated advanced non-small-cell lung cancer (NSCLC).

METHODS

Treatment-naïve patients with EGFR-mutated advanced NSCLC were enrolled at many hospitals in Taiwan. Patient characteristics and the effectiveness and safety of afatinib, gefitinib, and erlotinib were compared.

RESULTS

This study enrolled 1,343 treatment-naïve patients with EGFR-mutated advanced NSCLC, of whom 554 were aged <65 years, 383 were aged 65-74 years, 323 were aged 75-84 years, and 83 were aged ≥85 years. For elderly patients, afatinib was more effective, with a median progression-free survival (PFS) of 14.7 months and overall survival (OS) of 22.2 months, than gefitinib (9.9 months and 17.7 months, respectively) and erlotinib (10.8 months and 18.5 months, respectively; PFS: p = 0.003; OS: p = 0.026). However, grade ≥3 adverse events, including skin toxicities, paronychia, mucositis, and diarrhea, were more frequently experienced by patients receiving afatinib than those receiving gefitinib or erlotinib.

CONCLUSIONS

This large retrospective study provides real-world evidence of the effectiveness and safety of EGFR-TKIs for elderly patients with EGFR-mutated advanced NSCLC, a population that is often underrepresented in clinical trials and real-world evidence. Afatinib was more effective as a first-line treatment than gefitinib or erlotinib for elderly patients with EGFR-mutated advanced NSCLC.

Insights into EGFR Mutations and Oncogenic KRAS Mutations in Non-Small-Cell Lung Cancer

Genetic mutations can activate different sets of proto-oncogenes and tumor suppressors genes [...].

Favorable Conditions for the Detection of EGFR T790M Mutation Using Plasma Sample in Patients with Non-Small-Cell Lung Cancer

BACKGROUND

Detection of the epidermal growth factor receptor (EGFR) T790M mutation using plasma samples has been considered simple and non-invasive, but the relatively high false negative results lead to additional tissue sampling in some patients. Until now, the characteristics of patients who prefer liquid biopsy have not yet been established.

METHODS

To evaluate the favorable conditions for the detection of T790M mutations using plasma samples, a multicenter retrospective study was performed between May 2018 and December 2021. Patients whose T790M mutation was detected in a plasma sample were classified as the plasma positive group. Study subjects with a T790M mutation not detected in a plasma sample but only in a tissue sample were grouped as the plasma false negative group.

RESULTS

Plasma positive and plasma false negative groups were found in 74 and 32 patients, respectively. As a result, 40% of patients with one or two metastatic organs at the time of re-biopsy had false negative plasma sample results, and 69% of patients with three or more metastatic organs at the time of re-biopsy had positive plasma results. In multivariate analysis, three or more metastatic organs at initial diagnosis were independently associated with the detection of a T790M mutation using plasma samples.

CONCLUSION

Our results demonstrated that the detection rate of a T790M mutation using plasma samples was related to the tumor burden, particularly to the number of metastatic organs.

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

Epidermal growth factor receptor (EGFR) triple mutations with exon 19 deletion (del19), T790M, and cis-C797S (del19/T790M/cis-C797S mutations) frequently occur in patients with non-small cell lung cancer (NSCLC), while progression to frontline EGFR-tyrosine kinase inhibitors (TKIs) and osimertinib was resistant to all clinically available EGFR-TKIs. Brigatinib monotherapy may be a potential treatment for NSCLC harboring del19/T790M/cis-C797S mutations based on preclinical studies; however, no clinical report has evaluated its efficacy on EGFR del19/T790M/cis-C797S mutations. Herein, we present a case of a female patient with EGFR del19-mutated NSCLC treated with afatinib followed by osimertinib due to acquired T790M mutation. The EGFR del19/T790M/cis-C797S mutations were detected following osimertinib treatment. Complete response of skull metastasis was confirmed after brigatinib treatment (90 mg daily). Unfortunately, she experienced intolerable adverse events; therefore, brigatinib was discontinued after three-month usage. This report provides the first reported evidence for the use of brigatinib monotherapy in patients with NSCLC harboring EGFR del19/T790M/cis-C797S mutations after progression to previous EGFR-TKIs.