Recent understanding of the molecular mechanisms for the efficacy and resistance of EGF receptor-specific tyrosine kinase inhibitors in non-small cell lung cancer

Introduction: The epidermal growth factor receptor (EGFR) and its family members are involved in many aspects of tumor biological processes. Aberrant activation of the EGFR tyrosine kinase by mutations or protein overexpression is observed in various types of human cancer, including lung cancer. EGFR tyrosine kinase inhibitors (EGFR-TKIs), such as gefitinib and erlotinib, are highly effective in lung cancer patients who harbor active mutations in the EGFR gene. However, patients who are initially sensitive to EGFR-TKIs eventually relapse within few years.

Areas covered: Non-small cell lung cancer (NSCLC) is the most common type of lung cancer and is associated with a high frequency of EGFR mutations. This review describes the EGFR mutations that determine the sensitivity to EGFR-TKIs and the current understanding of the molecular mechanisms of acquired resistance to EGFR-TKIs in NSCLC. Furthermore, the authors describe recent strategies developed to overcome acquired resistance using second-generation EGFR-TKIs and combination therapies with several molecular-targeting drugs.

Expert opinion: Although recent findings have contributed to our understanding of the mechanism of acquired resistance and helped the development of novel strategies to overcome such resistance, the underlying mechanisms are complex and additional research is necessary to develop effective therapeutic strategies for individual patients with lung cancer.     

Osimertinib for EGFR T790M mutation-positive non-small cell lung cancer

Introduction: Significant advances have been made since the development of epidermal growth factor receptor tyrosine kinase inhibitors (EGFR-TKIs) targeting EGFR mutations in non-small-cell lung cancer (NSCLC), however, lung cancer cells eventually acquire resistance to those agents. Osimertinib (AZD9291) has been developed as 3^rd generation EGFR-TKI with activities against sensitizing mutations and T790 M resistance mutation, which account for about 50% of the mechanisms of acquired resistance to 1^st or 2^nd generation EGFR-TKIs. A recent phase I/II clinical trial with osimertinib for advanced NSCLC patients with known sensitizing EGFR mutations and documented disease progression on prior EGFR-TKIs revealed promising effect with acceptable toxicities.

Areas covered: This article summarizes current understanding and available preclinical and clinical data on osimertinib and also discusses future directions. The literature search included PubMed and the latest articles from international conferences.

Expert commentary: The development of osimertinib has provided new therapeutic options for NSCLC patients harboring T790 M. Compared with other EGFR-TKIs including rociletinib, osimertinib seems to possess an advantage with respect to the effect and safety profile among existing EGFR-TKIs. However, tumor progression still occurs even when treating with osimertinib. A further understanding of the mechanisms of resistance is eagerly anticipated in order to develop next generation EGFR-TKIs.     

Gefitinib for non-small-cell lung cancer treatment

Introduction: Gefitinib is an EGFR tyrosine kinase inhibitor (EGFR-TKI) that demonstrated efficacy in patients with advanced non-small cell lung cancer (NSCLC) across therapy lines. In the first-line setting, recent randomized Phase III trials comparing EGFR-TKIs versus platinum-based doublets demonstrated that in patients harboring an activating EGFR mutation, gefitinib is superior to chemotherapy in terms of response rate, progression-free survival, toxicity profile and quality of life, with a marginal positive effect on survival. In order to choose the best treatment, a molecular characterization is now mandatory, as part of baseline diagnostic procedures.

Areas covered: All published data on gefitinib in lung cancer were analyzed using PubMed. The aim of this review is to summarize activity and safety data from major clinical trials of gefitinib in patients with advanced NSCLC.

Expert opinion: EGFR-TKIs including gefitinib are the best option we can offer today in patients with EGFR mutation, regardless of treatment line. Administration of gefitinib to patients with advanced NSCLC is usually well-tolerated and it also appears to be feasible in special populations characterized by a significantly poorer risk:benefit ratio with standard chemotherapy, like elderly patients and patients with poor performance status.     

Pharmacokinetic drug evaluation of osimertinib for the treatment of non-small cell lung cancer

Introduction: First- and second-generation epidermal growth factor receptor-tyrosine kinase inhibitors (EGFR-TKIs), such as gefitinib, erlotinib, icotinib, and afatinib are the standard-of-care for first-line therapy of non-small-cell lung cancer (NSCLC) harboring activating EGFR mutations. Unfortunately, after initial activity of an average 9–13 months, disease progression has been reported in the majority of patients. In about 50% of cases the progression is due to the onset of the T790M mutation in exon 20 of the EGFR gene. Third-generation EGFR-TKIs targeting this mutation were investigated, with osimertinib the only reaching clinical practice.

Areas covered: A structured search of bibliographic databases for peer-reviewed research literature and of main meetings using a focused review question addressing osimertinib, was undertaken.

Expert opinion: Osimertinib is the standard-of-care for EGFR-mutated patients progressing to first-line EGFR-TKIs due to the acquired EGFR T790M mutation. Results from the head-to-head first-line trial comparing osimertinib versus gefitinib or erlotinib in activating EGFR mutations might change the front-line approach. Osimertinib in combination regimens, such as immunotherapy, and in adjuvant setting are ongoing. Thus, the strategic approach for the management of EGFR-mutated NSCLC patients will change further in the next few years.     

Pharmacotherapy targeting the EGFR oncogene in NSCLC

Introduction: The EGFR plays a central role in regulating cancer cell growth and survival, representing an attractive therapeutic target in NSCLC.

Areas covered: For the purpose of this review article, data from Phase II and III trials with anti-EGFR agents, including EGFR-tyrosine kinase inhibitors (TKIs) and mAbs, were collected and analysed.

Expert opinion: Eight large Phase III trials demonstrated that EGFR-TKIs are the best option we can offer today as front-line therapy exclusively in EGFR mutant NSCLC. In patients with EGFR wild type or unknown lung cancer, platinum-based chemotherapy remains the standard of care, with no consistent benefit produced by the addition of an anti-EGFR treatment. In pretreated NSCLC, EGFR-TKIs are considered more effective than standard monotherapy with cytotoxics in presence of classical EGFR mutations, whereas in the EGFR wild-type population, a similar efficacy with docetaxel or pemetrexed in terms of survival has been demonstrated. New agents targeting EGFR are under investigation, particularly in individuals with squamous cell histology and those with acquired resistance to EGFR-TKIs.     

Antitumor activity of aumolertinib,a third-generation EGFR tyrosine kinase inhibitor,in non-small-cell lung cancer harboring uncommon EGFR mutations

Uncommon epidermal growth factor receptor (EGFR) mutations account for 10%–20% of all EGFR mutations in non-small-cell lung cancer (NSCLC). The uncommon EGFR-mutated NSCLC is associated with poor clinical outcomes and generally achieved unsatisfactory effects to the current therapies using standard EGFR-tyrosine kinase inhibitors (TKIs), including afatinib and osimertinib. Therefore, it is necessary to develop more novel EGFR-TKIs to treat uncommon EGFR-mutated NSCLC. Aumolertinib is a third-generation EGFR-TKI approved in China for treating advanced NSCLC with common EGFR mutations. However, it remains unclear whether aumolertinib is effective in uncommon EGFR-mutated NSCLC. In this work, the in vitro anticancer activity of aumolertinib was investigated in engineered Ba/F3 cells and patient-derived cells bearing diverse uncommon EGFR mutations. Aumolertinib was shown to be more potent in inhibiting the viability of various uncommon EGFR-mutated cell lines than those with wild-type EGFR. And in vivo, aumolertinib could also significantly inhibit tumor growth in two mouse allograft models (V769-D770insASV and L861Q mutations) and a patient-derived xenografts model (H773-V774insNPH mutation). Importantly, aumolertinib exerts responses against tumors in advanced NSCLC patients with uncommon EGFR mutations. These results suggest that aumolertinib has the potential as a promising therapeutic candidate for the treatment of uncommon EGFR-mutated NSCLC.     

Recent understanding of the molecular mechanisms for the efficacy and resistance of EGF receptor-specific tyrosine kinase inhibitors in non-small cell lung cancer

INTRODUCTION: The epidermal growth factor receptor (EGFR) and its family members are involved in many aspects of tumor biological processes. Aberrant activation of the EGFR tyrosine kinase by mutations or protein overexpression is observed in various types of human cancer, including lung cancer. EGFR tyrosine kinase inhibitors (EGFR-TKIs), such as gefitinib and erlotinib, are highly effective in lung cancer patients who harbor active mutations in the EGFR gene. However, patients who are initially sensitive to EGFR-TKIs eventually relapse within few years. AREAS COVERED: Non-small cell lung cancer (NSCLC) is the most common type of lung cancer and is associated with a high frequency of EGFR mutations. This review describes the EGFR mutations that determine the sensitivity to EGFR-TKIs and the current understanding of the molecular mechanisms of acquired resistance to EGFR-TKIs in NSCLC. Furthermore, the authors describe recent strategies developed to overcome acquired resistance using second-generation EGFR-TKIs and combination therapies with several molecular-targeting drugs. EXPERT OPINION: Although recent findings have contributed to our understanding of the mechanism of acquired resistance and helped the development of novel strategies to overcome such resistance, the underlying mechanisms are complex and additional research is necessary to develop effective therapeutic strategies for individual patients with lung cancer.     

Gefitinib for non-small-cell lung cancer treatment

INTRODUCTION: Gefitinib is an EGFR tyrosine kinase inhibitor (EGFR-TKI) that demonstrated efficacy in patients with advanced non-small cell lung cancer (NSCLC) across therapy lines. In the first-line setting, recent randomized Phase III trials comparing EGFR-TKIs versus platinum-based doublets demonstrated that in patients harboring an activating EGFR mutation, gefitinib is superior to chemotherapy in terms of response rate, progression-free survival, toxicity profile and quality of life, with a marginal positive effect on survival. In order to choose the best treatment, a molecular characterization is now mandatory, as part of baseline diagnostic procedures. AREAS COVERED: All published data on gefitinib in lung cancer were analyzed using PubMed. The aim of this review is to summarize activity and safety data from major clinical trials of gefitinib in patients with advanced NSCLC. EXPERT OPINION: EGFR-TKIs including gefitinib are the best option we can offer today in patients with EGFR mutation, regardless of treatment line. Administration of gefitinib to patients with advanced NSCLC is usually well-tolerated and it also appears to be feasible in special populations characterized by a significantly poorer risk:benefit ratio with standard chemotherapy, like elderly patients and patients with poor performance status.     

EML4-ALK融合介导EGFR-TKI耐药晚期肺腺癌个案报告

表皮生长因子受体（EGFR）基因突变和间变性淋巴瘤激酶（ALK）基因融合的发现显著改变了非小细胞肺癌的治疗模式，并使患者生存显著获益。ALK融合突变是EGFR酪氨酸激酶抑制剂（TKI）耐药的机制之一。我们报告了1例64岁晚期肺腺癌女性患者，其存在EGFR突变，并在EGFR-TKI耐药后发生了ALK融合，通过先后使用EGFR-TKI或ALK-TKI获得了长期生存，为ALK融合介导的EGFR-TKI耐药患者的靶向治疗药物选择提供参考。     

EGFR-TKIs治疗非小细胞肺癌进展

目前,肺癌依然是导致人类恶性肿瘤死亡的首位疾病。在过去10年中,EGFR-TKI药物的出现,显著改善了患者的生存,从而改变了肺癌的标准治疗模式。作为一线、二线或其他治疗,EGFR-TKI药物,包括吉非替尼和厄洛替尼,在特定人群中(腺癌、女性、非吸烟、亚裔患者)疗效显著。除上述两种药物,由浙江贝达药业有限公司研发的EGFR-TKIs埃克替尼也已经完成了其III期临床试验(ICOGEN),并取得可喜的结果。本文将对以上3种EGFR-TKI药物治疗非小细胞肺癌进展进行综述。     

晚期非小细胞肺癌EGFR-TKIs获得性耐药后治疗策略研究进展

肺癌是癌症相关死亡的首要原因。非小细胞肺癌（NSCLC）约占肺癌的85%,且患者在诊断时大多为晚期。随着表皮生长因子受体（EGFR）在肺癌中被发现,针对特定基因突变的靶向治疗成为晚期NSCLC的重要治疗方式,并显著延长了患者生存期。尽管第一、二、三代EGFR-酪氨酸激酶抑制剂（TKI）蓬勃发展,但随着治疗时间的推移,患者都可能面临耐药和进展。为克服这一难题,基于耐药机制的相关治疗策略正在研究中。本文旨在对近年来EGFR-TKIs,特别是在疗效及安全性上作为指南更优推荐的第三代EGFR-TKIs的耐药机制和治疗策略的研究进展进行综述。     

EGFR突变肺癌脑膜转移奥希替尼加量治疗1例

非小细胞肺癌（NSCLC）脑膜转移患者的生存期短,治疗方法有限。奥希替尼是第三代表皮生长因子受体酪氨酸激酶抑制剂（EGFR-TKI）,可高效抑制EGFR敏感突变和EGFR T790M耐药突变,同时对EGFR突变的NSCLC软脑膜转移患者也有很好的疗效。本文报道1例奥希替尼加量至160 mg·d^-1治疗EGFR突变肺腺癌脑膜转移,为临床治疗NSCLC难治性软脑膜转移提供参考。     

表皮生长因子受体-酪氨酸激酶抑制剂分子耐药机制研究

以表皮生长因子受体-酪氨酸激酶抑制剂(EGFR-TKI)为靶点的治疗近年逐渐引起关注。但部分患者在服用EGFR-TKI初期即出现原发和获得性耐药。本文综述EGFR-TKI分子耐药机制的研究现状,探讨EGFR-TKI分子耐药机制重要的临床意义。     

A review of the benefit–risk profile of gefitinib in Asian patients with advanced non‐small‐cell lung cancer

ABSTRACT

Background: Improvements in first-line therapy of advanced non-small-cell lung cancer (NSCLC) have increased the need for effective second-line treatment options. In a Phase II trial of the anticancer drug gefitinib (IRESSA), greater efficacy was observed in Japanese compared with non-Japanese patients. Furthermore, results from a placebo-controlled Phase III trial (IRESSA Survival Evaluation in Lung cancer [ISEL]) showed that treatment with gefitinib was not associated with a statistically significant improvement in survival in either the overall or adenocarcinoma co-primary populations, although there was marked heterogeneity in survival outcomes between patient groups, with patients of Asian origin achieving a significant survival benefit with gefitinib compared with placebo.

Objective: To review the benefit:risk profile of gefitinib in Asian patients with advanced NSCLC.

Research design and methods: We identified and reviewed 31 reports (each with ≥ 25 patients) of clinical experience with gefitinib 250?mg/day in Asia involving a total of > 2000 patients with refractory NSCLC in Japan, China, Korea and Taiwan by searching EMBASE and Medline databases for publications between 1 January 2003 and 1 July 2005.

Results and discussion: In the majority of these reports, objective response rates of > 25% and disease control rates of > 60% have been described. Treatment with gefitinib resulted in a median time to progression of > 3 months and a median survival time of > 6 months in most studies. These 31 reports also demonstrated the efficacy of gefitinib in patients with secondary brain metastases, those with poor performance status (PS) and in patients receiving the drug as first-line treatment. Female gender, adenocarcinoma histology, non-smoking history, good PS and the presence of multiple lung metastases are associated with improved responsiveness to gefitinib. Reflecting the results of previous clinical trials, the reports indicate that gefitinib is generally well tolerated by Asian patients. The incidence of interstitial lung disease appears to be higher in Japanese than non-Japanese patients, although the reasons for this are not clear. Recent findings regarding cellular and genetic factors that may underlie the increased responsiveness to gefitinib among Asian patients are discussed.     

奥希替尼一线治疗EGFR突变局部晚期或转移性非小细胞肺癌的成本效果分析

目的 对比奥希替尼与标准表皮生长因子受体-酪氨酸激酶抑制剂(EGFR-TKIs,吉非替尼或厄洛替尼)一线治疗EGFR突变的局部晚期或转移性非小细胞肺癌(NSCLC)的成本效果.方法 运用Markov模型,评价两种治疗策略下的总成本与总健康产出,总成本以元表示,总产出以质量调整生命年(QALYs)表示.根据FLAURA试...     

FoxM1 mediated resistance to gefitinib in non-smallcell lung cancer cells

Aim:

Gefitinib is effective in only approximately 20% of patients with non-small-cell lung cancer (NSCLC), and the underlying mechanism remains unclear. FoxM1 is upregulated in NSCLC and associated with a poor prognosis in NSCLC patients. In this study, we examined the possible role of FoxM1 in gefitinib resistance and the related mechanisms.

Methods:

Gefitinib resistant human lung adenocarcinoma cell line SPC-A-1 and gefitinib-sensitive human lung mucoepidermoid carcinoma cell line NCI-H292 were used. mRNA and protein expression of FoxM1 and other factors were tested with quantitative RT PCR and Western blot analysis. RNA interference was performed to suppress FoxM1 expression in SPC-A-1 cells, and lentiviral infection was used to overexpress FoxM1 in H292 cells. MTT assay and flow cytometry were used to examine the proliferation and apoptosis of the cells.

Results:

Treatment of SPC-A-1 cells with gefitinib (1 and 10 μmol/L) upregulated the expression of FoxM1 in time- and concentration-dependent manners, while gefitinib (1 μmol/L) downregulated in H292 cells. In SPC-A-1 cells treated with gefitinib (1 μmol/L), the expression of several downstream targets of FoxM1, including survivin, cyclin B1, SKP2, PLK1, Aurora B kinase and CDC25B, were significantly upregulated. Overexpression of FoxM1 increased the resistance in H292 cells, while attenuated FoxM1 expression restored the sensitivity to gefitinib in SPC-A-1 cells by inhibiting proliferation and inducing apoptosis.

Conclusion:

The results suggest that FoxM1 plays an important role in the resistance of NSCLC cells to gefitinib in vitro. FoxM1 could be used as a therapeutic target to overcome the resistance to gefitinib.     

Oxopyrido[2,3-d]pyrimidines as Covalent L858R/T790M Mutant Selective Epidermal Growth Factor Receptor (EGFR) Inhibitors

相似文献   

T790M突变与表皮生长因子受体酪氨酸激酶抑制剂继发耐药的相关性

目的:探讨表皮生长因子本酪氨酸激酶抑制剂(EGFR-TKIs)治疗晚期非小细胞肺癌继发耐药的机制。方法:用富集突变PCR(Mutation–enriched PCR)分析46例初治有效且维持≥6个月的晚期非小细胞肺癌患者的外周血和石蜡包埋组织标本的EGFR20外显子T790M突变,分析其与病理特征、疗效、无疾病进展生存时间(PFS)的相关性。结果:46例患者进展期外周血标本中,T790M突变率为39.13%(18/46例),明显高于治疗前标本中5.88%(2/34例)。T790M突变阳性者中位PFS为16.4个月(95%CI:10.83～17.47),野生型患者中位PFS10.2个月(95%CI:10.2～13.47)(P=0.6139)。结论:研究表明T790M突变与EGFR-TKIs继发耐药相关,在非小细胞肺癌患者中存在动态变化,与疗效和生存可能有一定相关性。     

Advances in chemotherapy in advanced non-small-cell lung cancer

Importance of the field: Lung cancer is the most common cancer in the world today, in terms of both incidence and mortality. Non-small-cell lung cancer (NSCLC) accounts for about 85% of all lung cancers diagnosis, and the majority of people diagnosed with NSCLC have advanced disease.

Areas covered in this review: In this review the main advances achieved in the medical treatment of advanced NSCLC are discussed, regarding both targeted therapies and chemotherapy. Among targeted therapies, recent data on the anti-vascular endothelial growth factor (VEGF) monoclonal antibody bevacizumab and the epidermal growth factor receptor tyrosyne kinase inhibitors (EGFR-TKIs) gefitinib and erlotinib are described. Among chemotherapeutic agents, the role of pemetrexed is discussed.

What the reader will gain: The reader will gain up-to-date information on the main advances, achieved in the last 3 years in the medical treatment of advanced NSCLC.

Take home message: Some recent advances have changed the face of the first-line chemotherapy of advanced NSCLC, giving physicians more options to tailor choice in this challenging setting.