Epidermal growth factor receptor tyrosine kinase inhibitors in previously treated advanced non-small-cell lung cancer with wild-type EGFR

Introduction: While epidermal growth factor receptor (EGFR) – tyrosine kinase inhibitors (TKIs) lead to longer progression-free survival (PFS) when compared with conventional chemotherapy in non-small-cell lung cancer (NSCLC) harboring activating EGFR mutations, the role of EGFR-TKI remains unclear in EGFR-wild-type (WT) NSCLC.

Areas covered: This article reviews selected data from randomized trials regarding the use of TKIs in EGFR-WT NSCLC. Nine randomized phase III trials have compared EGFR-TKI with chemotherapy in NSCLC patients in a second or later line setting. Two of these trials, TAILOR and DELTA, which were designed to investigate treatment benefits according to EGFR genotype, demonstrated that docetaxel chemotherapy displayed significantly better in progression-free survival (PFS) when compared with the EGFR-TKI erlotinib. Biomarkers to predict clinical benefits of the drug against EGFR WT tumor, and the efficacy of combination regimens using erlotinib or single-use afatinib against tumors are also covered in this article.

Expert opinion: Considering the modest benefits of erlotinib for EGFR-WT tumors, future studies are warranted, including the exploration of useful biomarkers and new treatment strategies for EGFT-TKI use, as well as the development of more sensitive EGFR mutation tests.     

Mechanisms of acquired resistance to epidermal growth factor receptor tyrosine kinase inhibitors and new therapeutic perspectives in non small cell lung cancer

EGFR somatic mutations define a subset of NSCLCs that are most likely to benefit from EGFR tyrosine kinase inhibitors (TKIs). These tumors are dependent on EGFR-signaling for survival. Recently, tyrosine kinase domain somatic mutations have been approved as criterion to decide first-line therapy in this group of advanced NSCLCs. Anyway, all patients ultimately develop resistance to these drugs. Acquired resistance is linked to a secondary EGFR mutation in about a half of patients. Uncontrolled activation of MET, another tyrosine kinase receptor, has been implicated in neoplastic invasive growth. MET is overexpressed, activated and sometimes mutated in NSCLC cell lines and tumor tissues. MET increased gene copy number has also been documented in NSCLC and has been studied as negative prognostic factor. It has also been found in about 20% of patients developing acquired resistance to TKIs inhibitors. In this group, it seems to display a new mechanism, which is able to mark tumor independence from EGFR signaling. The study of delayed resistance mechanisms could lead to the development of new therapeutic strategies. Different molecular alterations could be specifically targeted in order to extend disease control in this group of NSCLCs with distinct clinical and molecular features. EGFR irreversible inhibitors, MET inhibitors and dual EGFR/VEGFR inhibitors represent one of the most challenging issues in current clinical research. Ongoing clinical trials and future perspectives are discussed.     

Strategies to overcome resistance to tyrosine kinase inhibitors in non-small-cell lung cancer

The use of molecularly targeted agents has dramatically improved the prognosis of defined subsets of patients with non-small-cell lung cancer harboring somatically activated oncogenes, such as mutant EGFR or rearranged ALK. However, after initial marked responses to EGFR or ALK tyrosine kinase inhibitors (TKIs), almost all patients inevitably progress due to development of acquired resistance. Multiple molecular mechanisms of resistance have been identified; the best characterized are secondary mutations in the tyrosine kinase domain of the oncogene, such as T790M in EGFR and L1196M in ALK, which prevent target inhibition by the corresponding TKI. Other mechanisms include copy number gain of the ALK fusion gene and the activation of bypass signaling pathways that can maintain downstream proliferation and survival signals despite inhibition of the original drug target. Here, the authors provide an overview of the known mechanisms of resistance to TKIs and outline the therapeutic strategies, including new investigational agents and targeted therapies combinations, that have been developed to overcome resistance.     

表皮生长因子受体酪氨酸激酶抑制剂在肿瘤治疗中的应用

表皮生长因子受体 (EGFR)酪氨酸激酶 ,是细胞外信号传递到细胞内的重要枢纽 ,它在信号传导、细胞增殖、分化以及各种调节机制中发挥重要作用 ,在多种癌细胞中过度表达。许多研究表明 ,抑制EGFR酪氨酸激酶活性 ,可抑制肿瘤生长。目前 ,已有几种EGFR酪氨酸激酶抑制剂进入了临床试验。本文对几种EGFR酪氨酸激酶小分子抑制剂在肿瘤治疗中的研究进展做一综述。     

Second-generation epidermal growth factor tyrosine kinase inhibitors in non-small cell lung cancer

Inhibiting the tyrosine kinase activity of the epidermal growth factor receptor (EGFR) has an established role in the treatment of advanced non-small cell lung cancer. The first-generation EGFR inhibitors erlotinib and gefitinib have been approved for treatment in the second- and third-line setting. Second-generation EGFR tyrosine kinase inhibitors are now in development aiming to improve efficacy and overcome primary and secondary resistance to the first-generation drugs. The two most common strategies being used to achieve these aims are irreversible binding of drug to target and kinase multi-targeting. This is an overview of the early clinical development of selected second-generation tyrosine kinase inhibitors focusing on the treatment of non-small cell lung cancer.     

表皮生长因子受体(EGFR)酪氨酸激酶抑制剂的研究进展

表皮生长因子受体（EGFR）酪氨酸激酶介导的信号转导与肿瘤发生发展密切相关，抑制该受体活性可以有效地抑制肿瘤。近年来，许多以此为靶点的新抗肿瘤药物陆续被开发，在多种肿瘤治疗中取得了令人鼓舞的疗效。综述了EGFR的结构和作用以及近年来EGFR酪氨酸激酶抑制剂的研究进展。     

Epidermal growth factor receptor inhibitors in non-small-cell lung cancer

The epidermal growth factor receptor (EGFR) is a cell membrane receptor that plays a key role in cancer development and in the progression of many human malignancies, including non-small-cell lung cancer (NSCLC). EGFR-dependent signaling is involved in cancer cell proliferation, apoptosis, angiogenesis, invasion and metastasis. Targeting the EGFR is a valuable molecular approach in cancer therapy. This receptor is overexpressed in up to 80% of NSCLC cases. Thus, several molecules inhibiting this critical biologic pathway have been synthesized and tested as a single agent or in combination with other anticancer modalities in a wide of clinical trials, including reversible and irreversible small tyrosine kinase inhibitors, such as gefitinib and erlotinib, dual vascular endothelial growth factor receptor EGFR tyrosine kinase inhibitors, such as vandetanib (ZD-6474), and monoclonal antibodies, such as cetuximab, which have shown promising activity in patients with NSCLC. This review focuses on the preclinical and clinical results available with EGFR inhibitors in the treatment of NSCLC patients.     

Vascular endothelial growth factor receptor tyrosine kinase inhibitors for the treatment of advanced non-small cell lung cancer

ABSTRACT

Introduction: Angiogenesis is the process by which the tumor develops its potential for growth and distant metastasis. The main proangiogenic switch is vascular endothelial growth factor (VEGF), which, along with its receptor VEGFR, is a target for biological drugs such as multi-targeted tyrosine kinase inhibitors used for many neoplasms, including non-small cell lung cancer (NSCLC).

Areas covered: The fact that angiokinase inhibitors act on several signaling molecules simultaneously means that the use of alternative transmission pathways, which nullifies the effect of drugs directed against a single target, is avoided. Nevertheless, most of these drugs have failed to improve any outcome in NSCLC patients. The authors discuss these points and provide their expert perspectives.

Expert opinion: Multikinase inhibitors are the fruit of research which regards cancer as a complex system of interacting processes. However, the lack of predictive biomarkers of response has limited the development of this class of drugs in NSCLC. Combination trials with chemotherapy, immunotherapy or other targeted drugs are ongoing, and while some have already confirmed the role of antiangiogenic small molecules in integrated regimes, others are still evaluating the efficacy of these drugs and raising questions about their cost and tolerability.     

Targeting epidermal growth factor receptor in the treatment of non-small-cell lung cancer

Importance of the field: The management of non-small-cell lung cancer (NSCLC) has undergone a paradigm shift in the last decade, with the survival advantage demonstrated by the incorporation of anti-epidermal growth factor receptor (EGFR) agents to the standard treatment of advanced/metastatic NSCLC.

Areas covered in this review: We review the existing data regarding the distinct anti-EGFR agents in the NSCLC treatment and the potential role of the investigated biomarkers in the clinical outcome.

What the reader will gain: Tyrosine kinase inhibitors have been used in first-line, second-line and more settings with extremely good results in a subgroup of patients. Cetuximab remains the only anti-EGFR monoclonal antibody to show survival benefit when combined with a cytotoxic agent in the front-line setting. Anti-EGFR treatment is associated with a dramatic clinical benefit in a subgroup of patients, emphasizing the importance of customizing treatment. Several biomarkers have been investigated for their predictive or prognostic value. Validation of identification of biomarkers remains a focus of intense research that may ultimately guide therapeutic decision making, as none of these is considered ideal to discriminate responding from non-responding patients. However, the current evidence of the EGFR mutation analysis from a recent randomised trial suggests that EGFR mutation analysis is quite a good predictive marker for responsiveness to anti-EGFR TKIs. Moreover, the identification of surrogate markers to indicate optimal activity of the anti-EGFR agent is also needed. This review article provides data from large clinical trials using anti-EGFR agents and correlates these results with the tested biomarkers.

Take home message: EGFR inhibition has shown very encouraging results and has improved the outcome of the NSCLC treatment. However, a plateau of significant clinical benefit seems to have been reached and we believe that the time to move away from the traditional treatment approach to more individualizing therapies has come.     

表皮生长因子受体酪氨酸激酶抑制剂的研究与应用进展

表皮生长因子受体(EGFR)是ErbB家族的成员,在细胞增殖、存活、迁移、黏附和分化方面发挥重要作用,其过表达与多种实体肿瘤相关,并已成为治疗非小细胞肺癌(NSCLC)的重要靶标。为了克服体内EGFR蛋白突变引起的通路异常激活及耐药性的问题,先后开发了3代EGFR酪氨酸激酶(TK)抑制剂用于临床治疗。第一代和第二代抑制剂因其获得性耐药和较大的不良反应而在临床应用中逐年减少。第三代EGFR-TK抑制剂奥西替尼不仅有效克服了甲硫氨酸(T790M)突变产生的耐药问题,同时保留了对野生型EGFR的选择性,极大地降低了不良反应,在临床上得到了广泛应用。然而部分患者在用药后发生EGFR C797S突变,从而产生耐药性,针对此突变的第四代EGFR-TK抑制剂已有报道。本文对EGFR及其抑制剂发展与临床应用的基本情况、近年来第三代及第四代EGFR-TK抑制剂的研究进展等进行综述,并对未来EGFR-TK抑制剂的发展前景进行展望。     

表皮生长因子受体酪氨酸激酶抑制剂的耐药机制及其治疗策略

表皮生长因子受体酪氨酸激酶抑制剂在治疗非小细胞肺癌中取得了较好的疗效,但最终仍会出现耐药导致的肿瘤进展。目前的研究发现其中涉及的耐药机制多样,本文就近年来在非小细胞肺癌小分子酪氨酸激酶抑制剂治疗中存在的耐药机制及其治疗策略进行综述。     

治疗非小细胞肺癌新药:表皮生长因子受体酪氨酸激酶抑制剂-dacomitinib

Dacomitinib是一种由辉瑞制药公司研发的第2代口服表皮生长因子受体酪氨酸激酶抑制剂。2018年9月27日,美国食品和药物管理局批准dacomitinib用于EGFR第19外显子缺失突变或第21外显子L858R替换突变的转移性NSCLC患者的一线治疗。本文主要介绍其作用机制、药动学、临床研究及安全性。     

Epidermal growth factor receptor tyrosine kinase inhibitors

Clinical trials of selective small-molecule inhibitors of epidermal growth factor receptor tyrosine kinase activity have shown that these targeted inhibitors of proliferative signal transduction provide well-tolerated antitumour activity in patients. Preclinical pharmacology studies illustrate the potential use of these new cancer therapeutics in combination with chemotherapy, radiotherapy and hormone therapy, and in chemoprevention, in a spectrum of solid human tumours.     

Targeting epidermal growth factor receptor: Central signaling kinase in lung cancer

Non-small cell lung cancer (NSCLC) is the leading cause of cancer mortality worldwide. Platinum-based doublets remain the current standard therapy for advanced NSCLC. However, overall survival (OS) has reached a plateau, even with the improvement in these regimens. Advances in the knowledge of molecular mechanisms of carcinogenesis have prompted the development of many novel molecular-targeted agents including the epidermal growth factor receptor tyrosine kinase inhibitors (EGFR-TKIs). Results of the recent phase III IPASS trial showed that the EGFR-TKI gefitinib has a superior progression-free survival (PFS) to the most commonly used platinum-based doublet carboplatin-paclitaxel as the first-line chemotherapy for pulmonary lung adenocarcinoma among nonsmokers in East Asia. This trial also demonstrated that the presence of EGFR mutation is the best predictor of gefitinib treatment compared with the other biomarkers including EGFR gene copy number. Despite the therapeutic benefit of EGFR-TKIs in NSCLC, most patients eventually develop resistance to these drugs. A secondary mutation of EGFR (T790M) and amplification of MET account for 70% of all cases of acquired resistance to EGFR-TKIs. This review summarizes the significance of EGFR mutations and the mechanisms of resistance to EGFR-TKIs in NSCLC, both of which are critical for patient selection to extend survival as well as to overcome resistance in NSCLC patients treated with EGFR-TKIs.     

表皮生长因子受体酪氨酸激酶抑制剂相关性皮肤毒性的全球研究现状和诊治进展

随着肿瘤分子生物学理论研究和生物工程技术的进展,分子靶向治疗已成为未来肿瘤诊治的风向标。然而,皮肤毒性作为分子靶向治疗药物,特别是人表皮生长因子受体酪氨酸激酶抑制剂(EG-FR-TKI)类药物最常见的不良反应,已严重影响患者的诊疗效果和生活质量,甚至导致药物减量或中止治疗。近年来,人们对EGFR-TKI相关性皮肤毒性的关注角度正悄然发生改变,从最初的疗效评价标准未给予治疗到现今重视生活质量给予个体化系统治疗,体现了人们对肿瘤患者的诊治逐渐转向"以患者为中心,以医生为辅助,以靶向治疗为利器"的个体化、人文化治疗理念。本研究主要从皮肤毒性的发病机制、评估标准和治疗原则3个方面对EGFR-TKI相关性皮肤毒性的全球研究现状和诊治进展进行汇总,供临床医师参考。     

表皮生长因子受体酪氨酸激酶抑制剂在肺癌以外的应用进展

表皮生长因子受体酪氨酸激酶抑制剂(epidermal growth factor receptor tyrosine kinase inhibitor,EGFR-TKIs)主要用于晚期非小细胞肺癌的分子靶向治疗,随着EGFR-TKIs的越来越深入研究,发现EGFR及其配体参与了包括乳腺癌、胰腺癌等在内的不同人类癌症发病过程。因此,EGFR-TKIs的治疗对象也不再局限于晚期非小细胞肺癌,其对乳腺癌、胰腺癌、头颈癌、食管癌和宫颈癌等恶性肿瘤也有较好的抑制作用,并且与EGFR-TKIs联合用药往往比单独用药效果更好。该文讨论了EGFR-TKIs在治疗肺癌以外其他癌症的应用研究,以及EGFR-TKIs与其他药物联合治疗乳腺癌、胰腺癌等恶性肿瘤的潜在应用前景。