A retrospective real-world study: the efficacy of immune-related combination therapies in advanced non-small cell lung cancer after resistance to EGFR-TKIs.

BACKGROUND: Whether patients with advanced non-small cell lung cancer (NSCLC) should choose an immune-combination therapy regimen after EGFR-tyrosine kinase inhibitors (EGFR-TKIs) resistance is currently unclear. METHODS: We evaluated 118 NSCLC patients treated by immune checkpoint inhibitors (ICIs) + chemotherapy (I + C), ICIs + chemotherapy + antiangiogenic therapy (I + C + A), chemotherapy + antiangiogenic therapy (C + A) after inefficacy of EGFR-TKIs. We assessed the objective remission rate (ORR), disease control rate (DCR), and progression-free survival (PFS) of these treatments. RESULTS: The ORR was 26.1% vs 38.2% vs 16.3% in the three groups (P = 0.093). The divergence in DCR was also statistically significant (65.2% vs 85.3% vs 74.4%, P = 0.209). The median PFS was no statistically significant difference in PFS (3.09 vs 6.31 vs 5.91 months, P = 0.809), but the Kaplan-Meier survival curve of 12-month-PFS indicated an apparent survival advantage in the I + C + A group (P = 0.001). In addition, the I + C/I + C + A group showed higher median PFS than the C + A group in patients with brain metastases (median PFS, 6.44 vs 4.21 months, P = 0.022). The divergence in ORR of patients in the brain group was also statistically significant (P = 0.045). The I + C + A group showed superior efficacy in patients with liver metastases (median PFS, 0.95 vs 6.44 vs 3.48 months, P < 0.0001). The Cox proportional hazard modeling analysis suggested that the age, brain metastases, and liver metastases were all connected with the prognosis. CONCLUSIONS: This study suggests that advanced NSCLC patients after resistance to EGFR-TKIs may achieve better outcomes from triple therapy. Patients with brain metastases favor ICIs-related combination therapies and patients with liver metastases prefer I + C + A therapy.

Clinical impact of tetracyclines and/or proton pump inhibitors on the efficacy of epidermal growth factor receptor inhibitors in non-small cell lung cancer: a retrospective cohort study.

BACKGROUND: This retrospective cohort study examined the impact of tetracyclines (TCs) and proton pump inhibitors (PPIs) alone or in combination on the efficacy of epidermal growth factor receptor tyrosine kinase inhibitors (EGFR-TKIs) in patients with non-small cell lung cancer (NSCLC). METHODS: Patients with NSCLC treated with gefitinib or erlotinib for at least 1 week between January 2009 and October 2021 were enrolled and divided into four groups based on the presence/absence of TC and/or PPI in the therapeutic regimen: TC-/PPI-, TC + /PPI-, TC-/PPI + , TC + /PPI + . Progression-free survival (PFS) and overall survival (OS) were the primary and secondary endpoints, respectively. RESULTS: The estimated median PFS and OS of 347 included patients with NSCLC were 8.57 (95% confidence interval [CI]: 7.66-9.48) months and 13.10 (95% CI: 11.03-15.17) months, respectively. Co-administration of EGFR-TKIs with PPIs decreased the PFS and OS, while that with TCs improved the PFS and OS. However, the concomitant use of EGFR-TKIs, TCs, and PPIs yielded survival rates similar to that of EGFR-TKI therapy alone. CONCLUSIONS: The administration of EGFR-TKIs with other drugs poses a challenge in managing patients with NSCLC. Therefore, reassessing the indications and necessity of TC or PPI therapy is essential for patients receiving erlotinib or gefitinib. The benefits and risks of possible discontinuation due to the clinical relevance of this interaction should be considered.

First-line treatment with TKI plus brain radiotherapy versus TKI alone in EGFR-mutated non-small cell Lung cancer with brain metastases: a systematic review and meta-analysis.

BACKGROUND: It remains uncertain whether first-line treatment with upfront brain radiotherapy (RT) in combined with epidermal growth factor receptor tyrosine kinase inhibitors (EGFR-TKIs) is superior to EGFR-TKIs alone for EGFR-mutated non-small cell lung cancer with newly diagnosed brain metastases (BMs). Therefore, we performed a meta-analysis to address this issue. METHODS: We searched PubMed, Embase, Cochrane Library, and Web of Science databases for eligible studies published until February 28, 2023. The primary outcomes of interest were overall survival (OS) and intracranial progression-free survival (iPFS), reported as hazard ratios (HRs) and 95% confidence intervals (CIs). RESULTS: Twenty-four retrospective studies with 3184 patients were included. First- or second-generation EGFR-TKIs were used in each study. Upfront brain RT plus EGFR-TKIs significantly prolonged OS (HR = 0.75, 95% CI: 0.64-0.88) and iPFS (HR = 0.61, 95% CI: 0.52-0.72) compared to EGFR-TKIs alone. There were no significant differences in OS and iPFS benefits from the combination therapy between asymptomatic and symptomatic patients, patients with exon 19 and 21 mutations, patients with 1-3 and > 3 BMs, and males and females, respectively (HRs interaction, P > 0.05 for each subgroup comparison). CONCLUSIONS: First-line treatment with upfront brain RT plus EGFR-TKIs is likely to be more effective than EGFR-TKIs alone. The benefits of combination therapy did not appear to be significantly affected by BM-related symptoms, EGFR mutation subtype, number of BMs, or sex.

Association between dermatologic adverse events and quality of life in lung cancer patients treated with epidermal growth factor receptor-tyrosine kinase inhibitors.

PURPOSE: Epidermal growth factor receptor-tyrosine kinase inhibitors (EGFR-TKIs) are frequently associated with dermatologic adverse events (dAEs), having great impacts on patients' health-related quality of life (HRQoL) and treatment adherence. We aimed to examine the association between various dAEs and HRQoL in patients treated with EGFR-TKI therapy. METHODS: This was a cross-sectional study including 132 non-small-cell lung cancer (NSCLC) patients treated with gefitinib, erlotinib, afatinib, or osimertinib in Taiwan. The severity level of dAEs was graded by NCI-CTCAE v4.03 and PRO-CTCAE ITEMS v1.0. All participants answered the Functional Assessment of Cancer Therapy-Epidermal Growth Factor Receptor Inhibitors (FACT-EGFRI-18) HRQoL questionnaire. RESULTS: The clinician-reported severity of pruritus, photosensitivity, alopecia, and Karnofsky performance status was associated with HRQoL (ß = - 6.773, p = 0.046; ß = - 5.250, p = 0.032; ß = - 8.121, p = 0.001; ß = 0.327, p = 0.002; respectively). The clinician-reported severity of all dAEs except paronychia had negative correlations with HRQoL. The symptom gradings of CTCAE and PRO-CTCAE had positive correlation. CONCLUSIONS: The severity of pruritus, photosensitivity, and alopecia was associated with HRQoL of patients receiving EGFR-TKI therapy. Using patient-reported outcome measurements helps clinicians to capture the actual impact of symptoms on physical, social-emotional, and functional well-being.

Baseline anemia predicts a poor prognosis in patients with non-small cell lung cancer with epidermal growth factor receptor mutations: a retrospective study.

BACKGROUND: Anemia is relatively common in cancer patients, and baseline anemia is associated with poor survival in patients with non-small cell lung cancer (NSCLC). However, there is a lack of large-sample studies of patients with NSCLC with epidermal growth factor receptor (EGFR) mutations. METHODS: We retrospectively analyzed anemia­related data for patients with NSCLC and EGFR mutations who were admitted to Zhejiang Cancer Hospital from January 2013 to June 2019 and treated with targeted therapy. The patients' clinicopathological features were evaluated by χ2 tests and the relationships between clinical characteristics and prognosis were investigated using Kaplan-Meier and multivariate Cox regression analyses. RESULTS: A total of 2,029 patients treated with EGFR-tyrosine kinase inhibitors (TKIs) were finally enrolled in this study, of whom 24.6% had baseline anemia. Patients without baseline anemia had longer median overall survival (OS) than patients with baseline anemia (36.10 vs. 29.10 months, P = 0.001), and patients with grade < 2 anemia had longer median OS than those with grade ≥ 2 anemia (35.00 vs. 25.10 months, P < 0.001). Multivariate analyses identified baseline anemia as a factor predicting a poor prognosis in terms of OS in patients with EGFR mutations. CONCLUSIONS: Baseline anemia is a significant factor predicting a poor prognosis in terms of OS in patients with NSCLC and EGFR mutations treated with targeted therapy. A higher grade of baseline anemia may also be related to shorter OS. And a higher risk of EGFR-mutated patients who had received targeted therapy could also be observed.

[A review: drug-drug interactions of epithelial growth factor receptor-tyrosine kinase inhibitors].

Mutations in the epithelial growth factor receptor (EGFR) is a driving factor that causes non-small cell lung carcinoma (NSCLC). The epithelial growth factor receptor-tyrosine kinase inhibitors (EGFR-TKIs) is a crucial discovery in the treatment of lung cancer, particularly the efficacy of EGFR-TKIs is superior to that of the standard chemotherapy for patients with EGFR mutation-positive advanced NSCLC. Patients with NSCLC use EGFR-TKIs and other medications simultaneously is commonly seen, especially among those with comorbidities, which increases the risk of drug-drug interactions (DDIs) of EGFR-TKIs. The most common mechanisms underlying the DDIs of EGFR-TKIs are modulations of cytochrome P450 (CYP) and drug transporters [including P-glycoprotein (P-gp) and breast cancer resistance protein (BCRP)], as well as gastrointestinal acid-inhibitory drugs [proton pump inhibitors (PPIs) and H(2) receptor antagonists (H(2)RA)]. Inhibitors or inducers of CYP enzymes and drug transporters can inhibit or accelerate the metabolism of EGFR-TKIs, which increase or reduce the exposure of EGFR-TKIs, thereby affect the efficacy and safety of EGFR-TKIs. In addition, PPIs or H(2)RA can decrease the solubility, bioavailability and efficacy of EGFR-TKIs. This review summarizes the mechanisms of DDIs of gefitinib, erlotinib, icotinib, afatinib, dacomitinib and osimertinib; the management recommendations for DDIs of those EGFR-TKIs from the Chinese and global guideline, as well as from the recent pre-clinical and clinical studies, which provide the reference and evidence for managing the combination therapies of EGFR-TKIs and other medications in clinics.

Real-world utilization of EGFR TKIs and prognostic factors for survival in EGFR-mutated non-small cell lung cancer patients with brain metastases.

Brain metastases (BMs) cause morbidity and mortality in patients with non-small cell lung cancer (NSCLC). The optimal management of epidermal growth factor receptor (EGFR)-mutated NSCLC with BM is debatable. We aimed to investigate the impact of different treatments among patients with EGFR-mutated NSCLC. A cohort of 2058 lung cancer patients with BM between 2013 and 2018 was retrospectively studied. A total of 571 patients with EGFR-mutated NSCLC and BM were enrolled. All patients had received EGFR tyrosine kinase inhibitors (TKIs). Overall survival (OS) was measured from the diagnosis of BM to death or last follow-up. With a median follow-up of 35.2 months (95% confidence interval [CI], 31.8-38.6), the median survival after BM was 21.3 months (95% CI, 19.0-23.6). Osimertinib resulted in significantly superior survival after resistance to front-line TKIs (P < 0.0035); the median OS reached 28.0 months (95% CI, 23.0-32.9), and the T790M status showed no difference in clinical effectiveness (P = 0.386). The combination of TKIs and chemotherapy/vascular endothelial growth factor (VEGF) inhibitors (anti-VEGF) tended to have longer OS (P = 0.271). Intracranial local radiotherapy significantly improved survival (P = 0.0008). In multivariable analysis, we noted that age, Karnofsky performance score, EGFR mutation type, number of BMs and the presence of extracranial metastasis were independent pretreatment prognostic factors. In conclusion, EGFR TKIs have a significant effect on patients with EGFR-mutant BM, and the application of osimertinib further improves survival outcomes regardless of T790M status. Patients who undergo intracranial local therapy can achieve a survival benefit.

Efficacy and acquired resistance for EGFR-TKI plus thoracic SBRT in patients with advanced EGFR-mutant non-small-cell lung cancer: a propensity-matched retrospective study.

BACKGROUND: This retrospective study aimed to evaluate the efficacy of epidermal growth factor receptor (EGFR) tyrosine kinase inhibitors (TKIs) with stereotactic body radiation therapy (SBRT) and to elucidate potential mechanisms of acquired resistance. METHODS: Patients with advanced NSCLC harboring positive EGFR mutations after initial TKI therapy for at least 8 weeks were eligible for SBRT between August 2016 and August 2019. Eligible patients were treated with thoracic SBRT, and TKI was continued after SBRT until it was considered ineffective. The control group was treated with TKIs monotherapy. Propensity score matching (PSM, ratio of 1:2) was used to account for differences in baseline characteristics. Overall survival (OS), progression-free survival (PFS), treatment safety and resistance mechanisms were evaluated. RESULTS: Three hundred eight patients were included in the study population. Among them, 262 patients received TKIs alone, and 46 patients received TKIs with SBRT. Baseline characteristics were not significantly different between the two cohorts after PSM. The median PFS was 19.4 months in the TKIs +SBRT group compared to 13.7 months in the TKIs group (p = 0.034). An influence on OS has not yet been shown (p = 0.557). Of the 135 patients evaluated after PSM, 28 and 71 patients in the TKIs and TKIs +SBRT cohorts, respectively, had plasma cell-free DNA (cfDNA) next-generation sequencing (NGS) performed at baseline and disease progression. In the TKIs +SBRT cohort, the NGS results showed that T790M mutations were detected in 64.3% (18/28) of patients. Patients in the TKIs cohort exhibited fewer T790M-positive mutations (40.8%, p = 0.035) compared to patients in the TKIs +SBRT cohort. CONCLUSION: Real world data prove that TKIs plus thoracic SBRT significantly extend PFS with tolerable toxicity. The mutation ratio of T790M was increased in the TKIs +SBRT group compared to the TKIs only group. Further randomized studies are warranted.

Hepatotoxicity with epidermal growth factor receptor tyrosine kinase inhibitors in non-small-cell lung cancer patients: A network meta-analysis.

WHAT IS KNOWN AND OBJECTIVE: The efficacy of epidermal growth factor receptor tyrosine kinase inhibitors (EGFR-TKIs) in patients diagnosed with non-small-cell lung cancer (NSCLC) has been confirmed by a large number of studies. However, hepatotoxicity caused by EGFR-TKIs has not been widely investigated. This review compares the hepatotoxicity of different EGFR-TKIs through a network meta-analysis. METHODS: PubMed, EMBASE, Cochrane Library and ClinicalTrials.gov were systematically searched from their individual inceptions to 20 May 2020 with the goal of identifying randomized controlled trials (RCTs) reporting hepatotoxicity in NSCLC patients receiving EGFR-TKIs. A random-effects pairwise meta-analysis and network meta-analysis were performed within a frequentist framework. Risk ratios (RRs) and 95% confidence intervals (CIs) were calculated. RESULTS: Twelve eligible RCTs, including data from 6,280 patients diagnosed with NSCLC, were analysed. In our network meta-analysis, gefitinib was associated with a higher risk for hepatotoxicity compared to placebo (RR, 2.55; 95% CI, 1.32-4.89) and dacomitinib (RR, 2.60; 95% CI, 1.30-5.20) in terms of all-grades alanine transaminase (ALT) elevation. As for all-grades aspartate transaminase (AST) elevation, gefitinib and erlotinib showed a significantly increased risk for hepatotoxicity compared to afatinib, dacomitinib and placebo (erlotinib vs. afatinib: RR, 1.85; 95% CI, 1.05-3.24; erlotinib vs. dacomitinib: RR, 1.68; 95% CI, 1.19-2.36; erlotinib vs. placebo: RR, 3.38; 95% CI, 1.69-6.73; gefitinib vs. afatinib: RR, 2.23; 95% CI, 1.32-3.79; gefitinib vs. dacomitinib: RR, 2.03; 95% CI, 1.51-2.73; gefitinib vs. placebo: RR, 4.08; 95% CI, 2.11-7.91). There was a high risk of high-grade ALT elevation in patients treated with gefitinib compared to patients treated with erlotinib (RR, 4.31; 95% CI, 2.15-8.66), dacomitinib (RR, 6.95; 95% CI, 1.85-26.05) or placebo (RR, 8.38; 95% CI, 1.56-45.01). No statistically significant differences were identified among the five agents analysed in terms of all-grades TB elevation and high-grade AST elevation. The surface under the cumulative ranking curve (SUCRA) revealed that gefitinib showed a potentially higher risk for ALT and AST elevation compared to other EGFR-TKIs regardless of grade. WHAT IS NEW AND CONCLUSION: Current evidence indicates that the association between afatinib or dacomitinib and risk of liver enzyme elevation remains uncertain in patients diagnosed with NSCLC. Some evidence suggests that gefitinib and erlotinib may be associated with a significantly increased risk for hepatotoxicity in patients with NSCLC. However, given that the elevation of liver enzymes was not definitely associated with EGFR-TKIs and publication bias, further studies are required to confirm these results.

Comparing the effectiveness of different EGFR-TKIs in patients with EGFR mutant non-small-cell lung cancer: A retrospective cohort study in Taiwan.

The study was to compare the effectiveness of different epidermal growth factor receptor-tyrosine kinase inhibitors (EGFR-TKIs) in patients with advanced non-small-cell lung cancer (NSCLC) and received EGFR-TKIs as first-line therapy. This retrospective cohort study was conducted using data from real-world settings. Patients with stage IIIB and IV NSCLC and first received gefitinib, erlotinib, or afatinib between 2011 and 2015 were included. The date of the first claim for EGFR-TKIs was set as the index date. Study endpoints were all-cause death and treatment failure that was defined when patients added on or switched to chemotherapy or terminal care. A total of 5,940 patients, including 3,982 (67.0%) receiving gefitinib, 1,207 (20.3%) receiving erlotinib, and 751 (12.7%) receiving afatinib, were eligible for this study. The 1-year overall survival (OS) rates for gefitinib, erlotinib, and afatinib groups were 74% (95% confidence interval [CI]: 72-75%), 75% (95% CI: 73-77%), and 80% (95% CI: 77-83%), respectively. Compared to gefitinib, afatinib was associated with a lower risk of all-cause death (adjusted hazard ratio [aHR] = 0.82, 95% CI: 0.72-0.93) but not erlotinib (aHR = 0.95, 95% CI: 0.86-1.05). Similar results were also found regarding the effectiveness of treatment. All the three EGFR-TKIs showed no differences for both outcomes among patients with an Eastern Cooperative Oncology Group Performance Score of 2. The real-world data exhibited afatinib was more likely to be used for younger patients in a better condition than other EGFR inhibitors, and observed prolonged OS and treatment effectiveness compared to gefitinib after performing a multivariate Cox regression analysis.

Yiqi Chutan Tang Reduces Gefitinib-Induced Drug Resistance in Non-Small-Cell Lung Cancer by Targeting Apoptosis and Autophagy.

High incidence and mortality rates for non-small-cell lung cancer (NSCLC) lead to low survival rates. Epidermal growth factor receptor-tyrosine kinase inhibitors (EGFR-TKI) are commonly first prescribed for NSCLC patients with EGFR mutations. However, most patients with sensitizing EGFR mutations become resistant to EGFR-TKI after 9-13 months treatment. Yiqi Chutan Tang (YQCT) has been prescribed as a treatment to this issue for over 20 years. In this report, high-performance liquid chromatography (HPLC) analysis, flow cytometry, western blot analysis, and functional annotation analysis were applied to uncover the molecular mechanisms of YQCT. Our results show the application of YQCT reduces gefitinib-induced drug resistance, induces slight cell cycle arrest, enhances gefitinib-induced apoptosis, and activates the autophagy. These results indicate that at the molecular level YQCT can reduce drug resistance and improve anti-cancer effects when associated with gefitinib, which could be a result of enhancement of apoptosis and autophagy in the EGFR-TKI resistant cells of NSCLC. This research provides a new treatment strategy for patients with EGFR-TKI resistance in NSCLC. © 2019 The Authors. Cytometry Part A published by Wiley Periodicals, Inc. on behalf of International Society for Advancement of Cytometry.

SPOCK1 contributes to the third-generation EGFR tyrosine kinase inhibitors resistance in lung cancer.

INTRODUCTION: Explanation of the mechanism of resistance to third-generation epidermal growth factor receptor tyrosine kinase inhibitors (EGFR-TKIs) and the development of a novel strategy for drug resistance are imperative in third-generation EGFR-TKIs-resistant non-small cell lung cancer (NSCLC). SPOCK1 was found to be abnormally expressed in various tumors including lung cancer, however, there was no study focused on the role of SPOCK1 in third-generation EGFR-TKIs resistant lung cancer cells. METHODS AND RESULTS: We investigated the roles of SPOCK1 in NSCLC with third-generation EGFR-TKIs resistance. We showed that SPOCK1 was upregulated in the osimertinib-resistant lung cancer cells and knockdown of SPOCK1 inhibits osimertinib-resistant cells growth and overcomes resistance. Furthermore, we demonstrated that the SPOCK1 was higher in clinical NSCLC specimens compared with the normal lung tissues, and the higher expression of SPOCK1 correlated with poor prognosis. In addition, the overexpression of SPOCK1 in NSCLC tissues was positively correlated with MMP11 and TGFß1. CONCLUSION: Our study suggested that SPOCK1 could be an independent prognostic factor in NSCLC and would be a candidate for target therapy in osimertinib-resistant lung tumors.

[Application of radiomics captured from CT to predict the EGFR mutation status and TKIs therapeutic sensitivity of advanced lung adenocarcinoma].

Objective: To explore the ability of computed-tomography (CT) radiomic features to predict the Epidermal growth factor receptor (EGFR) mutation status and the therapeutic response of advanced lung adenocarcinoma to EGFR- Tyrosine kinase inhibitors (TKIs) treatment. Methods: A retrospective analysis was performed on 253 patients diagnosed as advanced lung adenocarcinoma, who underwent EGFR mutation detection, and those with EGFR sensitive mutation were treated with TKIs. Using the Lasso regression model and the 10 fold cross-validation method, the radiomic features of predicted EGFR mutation status and the screening of TKIs for sensitive populations were obtained. 715 radiomic features were extracted from unenhanced, arterial phase and venous phase, respectively. Results: The area under curve (AUC) values of the multi-phases including unenhanced, arterial phase and venous phase of the EGFR mutation status validation group were 0.763, 0.807 and 0.808, respectively. The number of radiomic features extracted from the multi-phases were 5, 18 and 23, respectively, which could distinguish the EGFR mutation status. The AUC values of the multi-phases of the EGFR-TKIs sensitive validation group were 0.730, 0.833 and 0.895, respectively. The number of radiomic features extracted from the multi-phases were 3, 7 and 22, respectively, which can be used to screen the superior population for TKIs treatment. The efficiency of radiomic features extracted from venous phase in predicting EGFR mutant status and EGFR-TKIs sensitivity was significantly superior than those of unenhanced and arterial phase. Conclusions: The radiomic features of CT scanning can be used as the radiomics biomarker to predict the EGFR mutation status of lung adenocarcinoma and to further screen the dominant population in TKIs therapy, which provides the basis for targeted therapy.

[Plasma relative abundance of epidermal growth factor receptor mutations predicts clinical response to epidermal growth factor receptor-tyrosine kinase inhibitors in patients with advanced lung adenocarcinoma].

Objective: To determine whether relative abundance of epidermal growth factor receptor (EGFR) mutations in plasma predicts clinical response to epidermal growth factor receptor-tyrosine kinase inhibitors (EGFR-TKIs) in patients with advanced lung adenocarcinoma. Methods: In this prospective study, adult patients with advanced lung adenocarcinoma were enrolled in our hospital from 1 April 2016 to 1 January 2017. EGFR mutations in tumor tissues were detected by ADx-amplification refractory mutation system (ADx-ARMS). EGFR mutations of plasma free tumor DNA were detected by ADx-ARMS and ADx-super amplification refractory mutation system (ADx-SuperARMS) at the same time. Patients with EGFR-mutant in tumor tissues and receiving EGFR-TKIs were finally enrolled. Plasma mutation-positive patients with both methods were high abundance group.Patients with positive mutations by ADx-SuperARMS but negative by ADx-ARMS were medium abundance group. Mutation-negative patients with both methods were recognized as low abundance group. The correlation between EGFR mutation abundance and clinical response to EGFR-TKIs were analyzed. Results: Among 71 patients enrolled, 42 harbored EGFR mutations in plasma were detected by ADx-ARMS, while 53 were found by ADx-SuperARMS.There were 42 patients in high abundance group, 11 in medium group while the other 18 in low group. The objective response rates (ORRs) were 69.0%, 7/11 and 10/18 in high, medium and low groups, respectively. The difference was significant between high and low abundances groups (P=0.006). Median progression-free survival (PFS) in high, medium and low groups were 11.0, 8.5 and 9.0 monthes, respectively (P<0.001). In patients with tumor 19-Del, the ORRs were 70.4%, 5/7 and 6/11 in high, medium and low abundance groups, respectively. The median PFS of high abundance group was significantly longer than the other two groups (12.0 monthes vs 9.0, 9.0 monthes). As to subjects with L858R mutation, the ORRs were 10/15, 2/4 and 3/6, respectively, with median PFS 9.6, 5.5 and 9.5 monthes. Conclusions: The relative abundance of EGFR mutations in plasma predicts clinical response to EGFR-TKIs in patients with advanced lung adenocarcinoma. The higher the mutation abundance is, the better the efficacy of EGFR-TKIs is.

Epidermal Growth Factor Receptor Tyrosine Kinase Inhibitors for Central Nervous System Metastases from Non-Small Cell Lung Cancer.

Central nervous system (CNS) metastases are a common complication in patients with epidermal growth factor receptor (EGFR)-mutated non-small cell lung cancer (NSCLC), resulting in a poor prognosis and limited treatment options. Treatment of CNS metastases requires a multidisciplinary approach, and the optimal treatment options and sequence of therapies are yet to be established. Many systemic therapies have poor efficacy in the CNS due to the challenges of crossing the blood-brain barrier (BBB), creating a major unmet need for the development of agents with good BBB-penetrating biopharmaceutical properties. Although the CNS penetration of first- and second-generation EGFR tyrosine kinase inhibitors (TKIs) is generally low, EGFR-TKI treatment has been shown to delay time to CNS progression in patients with CNS metastases from EGFR-mutated disease. However, a major challenge with EGFR-TKI treatment for patients with NSCLC is the development of acquired resistance, which occurs in most patients treated with a first-line EGFR-TKI. Novel EGFR-TKIs, such as osimertinib, have been specifically designed to address the challenges of acquired resistance and poor BBB permeability and have demonstrated efficacy in the CNS. A rational, iterative drug development process to design agents that could penetrate the BBB could prevent morbidity and mortality associated with CNS disease progression. To ensure a consistent approach to evaluating CNS efficacy, special consideration also needs to be given to clinical trial endpoints. IMPLICATIONS FOR PRACTICE: Historically, treatment options for patients who develop central nervous system (CNS) metastases have been limited and associated with poor outcomes. The development of epidermal growth factor receptor (EGFR) tyrosine kinase inhibitors (TKIs) has improved outcomes for patients with EGFR-mutated disease, and emerging data have demonstrated the ability of these drugs to cross the blood-brain barrier and elicit significant intracranial responses. Recent studies have indicated a role for next-generation EGFR-TKIs, such as osimertinib, in the treatment of CNS metastases. In the context of an evolving treatment paradigm, treatment should be individualized to the patient and requires a multidisciplinary approach.

Factors associated with efficacy of first-generation epidermal growth factor receptor tyrosine kinase inhibitors in non-small-cell lung cancer.

The finding of epidermal growth factor receptor tyrosine kinase inhibitors, which reflects a classical process of translational research, is a critical milestone for non-small-cell lung cancer treatment. Currently, epidermal growth factor receptor tyrosine kinase inhibitors are recommended as first-line therapy for non-small-cell lung cancer patients harboring epidermal growth factor receptor-sensitive mutations. The status of epidermal growth factor receptor mutation is widely acknowledged as superior to other clinical factors, such as smoking, gender, and histological types for predicting the response to epidermal growth factor receptor tyrosine kinase inhibitors. However, recent studies have shown that the efficacy might differ in patients with the same epidermal growth factor receptor-sensitive mutations, highlighting the need to investigate the putative factors related to the efficacy of epidermal growth factor receptor tyrosine kinase inhibitors. This article reviews the factors associated with clinical efficacy of first-generation epidermal growth factor receptor tyrosine kinase inhibitors, such as gefitinib and erlotinib, and analyzes their potential implications with respect to clinical application. In addition, new findings related to clinical practice with respect to epidermal growth factor receptor tyrosine kinase inhibitors efficacy were summarized in this article.

Synthesis and evaluation of osimertinib derivatives as potent EGFR inhibitors.

Osimertinib has been identified as a promising therapeutic drug targeting for EGFR T790M mutant non-small cell lung cancer (NSCLC). A new series of N-oxidized and fluorinated osimertinib derivatives were designed and synthesized. The cellular anti-proliferative activity, kinase inhibitory activity and the activation of EGFR signaling pathways of 1-6 in vitro were determined against L858R/T790M and wild-type EGFR, the antitumor efficacy in NCI-H1975 xenografts in vivo were further studied. Compound 2, the newly synthesized N-oxide metabolite in N,N,N'-trimethylethylenediamine side chain of osimertinib, showed a comparable kinase selectivity in vitro and a slightly better antitumor efficacy in vivo to osimertinib, making it valuable and suitable for the potential lung cancer therapy.

[Mechanism and clinical efficacy of third-generation epidermal growth factor receptor tyrosine kinase inhibitor in non-small cell lung cancer].

Epidermal growth factor receptor-tyrosine kinase inhibitors (EGFR-TKIs) are the standard treatment for non-small cell lung cancer (NSCLC) patients with EGFR activating mutations. However, most of patients will develop resistance to TKIs treatment due to the emergence of the T790M mutation. The third-generation EGFR-TKI is highly selective and efficient for activating mutants (EGFR sensitive mutations) and resistance mutant (T790M+ ). This review summarizes the mechanism and clinical efficacy of the third-generation EGFR-TKI in NSCLC patients.

Rebiopsy for patients with non-small-cell lung cancer after epidermal growth factor receptor-tyrosine kinase inhibitor failure.

Although third-generation epidermal growth factor receptor-tyrosine kinase inhibitors (EGFR-TKI) can overcome T790M-mediated resistance in non-small-cell lung cancer (NSCLC), rebiopsy to confirm T790M status is occasionally difficult. We aimed to investigate the current tendency and the limitations of rebiopsy in clinical practice. This study included 139 consecutive NSCLC patients with EGFR mutations, who had experienced progressive disease (PD) after EGFR-TKI treatment. We retrospectively reviewed patient characteristics, tumor progression sites and rebiopsy procedures. Of 120 patients (out of the original 139) who were eligible for clinical trials, 75 (63%) underwent rebiopsy for 30 pleural effusions, 32 thoracic lesions, four bone, two liver, and seven at other sites. Rebiopsy procedures included 30 thoracocentesis, 24 transbronchial biopsies, 13 computed tomography (CT)-guided needle biopsies and 8 other procedures. Of the 75 rebiopsied patients, 71 (95%) were pathologically diagnosed with malignancy; and 34 (45%) had available tissue samples for EGFR analyses. Of the 75 biopsied patients, 61 (81%) were analyzed for EGFR mutation, using tissue or cytology samples; T790M mutations were identified in 20 (33%) of the 61 patients. Of the 120 patients, 45 (38%) did not undergo rebiopsy, because of inaccessible tumor sites (n = 19), patient refusal (n = 6) or decision of physician (n = 10). In conclusion, among patients with EGFR mutations who had PD after EGFR-TKI treatment, 63% underwent rebiopsy. Most rebiopsy samples were diagnosed with malignancy. However, tissue samples were less available and T790M mutations were identified less frequently than in previous studies. Skill and experience with rebiopsy and noninvasive alternative methods will be increasingly important.

Oncogene swap as a novel mechanism of acquired resistance to epidermal growth factor receptor-tyrosine kinase inhibitor in lung cancer.

Mutant selective epidermal growth factor receptor-tyrosine kinase inhibitors (EGFR-TKIs), such as rociletinib and AZD9291, are effective for tumors with T790M secondary mutation that become refractory to first-generation EGFR-TKI. However, acquired resistance to these prospective drugs is anticipated considering the high adaptability of cancer cells and the mechanisms remain largely obscure. Here, CNX-2006 (tool compound of rociletinib) resistant sublines were established by chronic exposure of HCC827EPR cells harboring exon 19 deletion and T790M to CNX-2006. Through the analyses of these resistant subclones, we identified two resistant mechanisms accompanied by MET amplification. One was bypass signaling by MET amplification in addition to T790M, which was inhibited by the combination of CNX-2006 and MET-TKI. Another was loss of amplified EGFR mutant allele including T790M while acquiring MET amplification. Interestingly, MET-TKI alone was able to overcome this resistance, suggesting that oncogenic dependence completely shifted from EGFR to MET. We propose describing this phenomenon as an "oncogene swap." Furthermore, we analyzed multiple lesions from a patient who died of acquired resistance to gefitinib, then found a clinical example of an oncogene swap in which the EGFR mutation was lost and a MET gene copy was gained. In conclusion, an "oncogene swap" from EGFR to MET is a novel resistant mechanism to the EGFR-TKI. This novel mechanism should be considered in order to avoid futile inhibition of the original oncogene.