Personalizing therapy with targeted agents in non-small cell lung cancer

In the last 6 years, since the first reports of an association between somatic mutations in epidermal growth factor receptor (EGFR) exons 19 and 21 and response to EGFR tyrosine kinase inhibitors (TKIs), treatment of non-small cell lung cancer (NSCLC) has changed dramatically. Based on laboratory and clinical observations, investigators have anticipated that these mutations could be predictive of response to EGFR TKIs and numerous studies have confirmed that the presence of mutation was associated with longer survival in patients receiving targeted therapy. Prospective trials comparing standard platinum-based chemotherapy with EGFR TKIs in patients with and without activating EGFR mutations validated the predictive value of molecular selection of patients for first-line treatment of advanced NSCLC. Recently, preclinical and first-in-human studies have demonstrated impressive activity of ALK TKI in tumors harboring ALK rearrangement. In this article, we review current data on molecular biology of lung cancer and evidence-based patient selection for targeted therapy.     

奥希替尼治疗非小细胞肺癌的研究进展

表皮生长因子受体(EGFR)突变的发现以及EGFR酪氨酸激酶抑制剂(TKI)疗效的证明，标志着非小细胞肺癌(NSCLC)精准药物使用时代的到来。奥希替尼是针对EGFR TKI敏感突变和野生型EGFR T790M突变，同时保留野生型EGFR的第三代TKI。因其在临床试验中表现出的显著临床有效性和良好安全性，2015年及2016年初，美国及欧洲首次批准了奥希替尼用于接受EGFR TKI治疗后进展的EGFR T790M突变阳性的NSCLC患者的治疗，2017年3月奥西替尼正式在我国获批上市。本文主要就奥希替尼在NSCLC治疗中的研究进展进行综述。     

RAC1 inhibition as a therapeutic target for gefitinib‐resistant non‐small‐cell lung cancer

Although epidermal growth factor receptor (EGFR)‐tyrosine kinase inhibitors (EGFR‐TKI), including gefitinib, provide a significant clinical benefit in non‐small‐cell lung cancer (NSCLC) patients, the acquisition of drug resistance has been known to limit the efficacy of EGFR‐TKI therapy. In this study, we demonstrated the involvement of EGF‐EGFR signaling in NSCLC cell migration and the requirement of RAC1 in EGFR‐mediated progression of NSCLC. We showed the significant role of RAC1 pathway in the cell migration or lamellipodia formation by using gene silencing of RAC1 or induction of constitutive active RAC1 in EGFR‐mutant NSCLC cells. Importantly, the RAC1 inhibition suppressed EGFR‐mutant NSCLC cell migration and growth in vitro, and growth in vivo even in the gefitinib‐resistant cells. In addition, these suppressions by RAC1 inhibition were mediated through MEK or PI3K independent mechanisms. Collectively, these results open up a new opportunity to control the cancer progression by targeting the RAC1 pathway to overcome the resistance to EGFR‐TKI in NSCLC patients.     

TP53突变对非小细胞肺癌表皮生长因子受体突变患者酪氨酸激酶抑制剂的治疗效果和预后影响

基因突变能够影响肺癌细胞对靶向药物的敏感性,导致个体化临床治疗效果出现差异。表皮生长因子受体(EGFR)的突变状态在内科药物治疗决策中具有重要意义。此外,其他并存的基因突变均可影响疾病的治疗效果和患者的远期临床预后。EGFR突变合并TP53突变是否可改变肺癌细胞对酪氨酸激酶抑制剂治疗的敏感性和对远期预后的影响一直受到人们的关注。目前在临床实践中,TP53的突变状态并不是临床治疗决策中的参考依据,因此需要进一步的证据阐明TP53(包括各亚型)突变状态对EGFR靶向治疗潜在获益的影响,以指导非小细胞肺癌的治疗。     

Coregulation of pathways in lung cancer patients with EGFR mutation: therapeutic opportunities

Epidermal growth factor receptor (EGFR) mutations in lung adenocarcinoma are a frequent class of driver mutations. Single EGFR tyrosine kinase inhibitor (TKI) provides substantial clinical benefit, but almost nil radiographic complete responses. Patients invariably progress, although survival can reach several years with post-treatment therapies, including EGFR TKIs, chemotherapy or other procedures. Endeavours have been clinically oriented to manage the acquisition of EGFR TKI-resistant mutations; however, basic principles on cancer evolution have not been considered in clinical trials. For years, evidence has displayed rapidly adaptive mechanisms of resistance to selective monotherapy, posing several dilemmas for the practitioner. Strict adherence to non-small cell lung cancer (NSCLC) guidelines is not always practical for addressing the clinical progression that EGFR-mutant lung adenocarcinoma patients suffer. The purpose of this review is to highlight regulatory mechanisms and signalling pathways that cause therapy-induced resistance to EGFR TKIs. It suggests combinatorial therapies that target EGFR, as well as potential mechanisms underlying EGFR-mutant NSCLC, alerting the reader to clinical opportunities that may lead to a deeper and more durable response. Molecular reprogramming contributes to EGFR TKI resistance, and the compiled information is relevant in understanding the development of new combined targeted strategies in EGFR-mutant NSCLC.Subject terms: Drug development, Predictive markers, Cancer therapeutic resistance     

A novel EGFR nonsense mutation in a non-small-cell lung cancer (NSCLC) patient who did not derive any clinical benefit with combination chemotherapy and erlotinib

Most of the somatic epidermal growth factor receptor (EGFR) mutations described to date in non-smallcell lung cancer (NSCLC) patients are located in the kinase domain and are considered activating mutations. Some of these mutations are associated with response to specific EGFR tyrosine kinase inhibitors (TKI) such as gefitinib and erlotinib. Here we report a case of a previously undescribed EGFR nonsense mutation in a lung adenocarcinoma patient who did not derive any clinical benefit with combination chemotherapy and erlotinib. To the best of our knowledge this is the second report in the literature describing an EGFR nonsense mutation in lung cancer patients.     

Epidermal Growth Factor Receptor (EGFR) Kinase Inhibitors and Non-Small Cell Lung Cancer (NSCLC) – Advances in Molecular Diagnostic Techniques to Facilitate Targeted Therapy

A subset of patients with non-small cell lung cancer (NSCLC) respond well to epidermal growth factor receptor tyrosine kinase inhibitors (EGFR TKIs), due to the presence of sensitising mutations in the gene encoding EGFR. Mutations associated with resistance to first generation EGFR TKIs have also been identified, which lead to therapeutic failure and the requirement for new drugs. Three generations of EGFR TKIs have been developed and either have been, or are being, evaluated as first and/or second line therapeutic agents. In this review, we consider the advances in molecular diagnostic techniques that are used, or are in development, to facilitate the targeted EGFR TKI therapy of patients with NSCLC. A literature search was conducted in May 2017 using PubMed, and spanning the period September 2005 (EU approval date of erlotinib) to May 2017. Search terms used were: EGFR TKI, NSCLC, clinical trial, erlotinib, gefitinib, afatinib, EGFR mutations, Exon 19 deletion, and Leu858Arg. The use of molecular data, in conjunction with other clinical and diagnostic information, will assist physicians to make the best therapeutic choice for each patient with advanced NSCLC. Personalized medicine and a rapidly developing therapy landscape will enable these patients to achieve optimal responses to EGFR TKIs.     

EGFR mutations in malignant pleural effusion of non-small cell lung cancer: a case report

EGFR mutations have been shown to correlate with the clinical responsiveness to epidermal growth factor receptor tyrosine kinase inhibitor (EGFR-TKI). The detection of EGFR mutations in non-small cell lung cancer (NSCLC) is important from the perspective of targeted anticancer therapy. We report the first case showing that the status of EGFR mutations can be successfully determined in malignant pleural effusion of NSCLC using polymerase chain reaction (PCR) technique, and correlated to the clinical responsiveness to gefitinib, an EGFR-TKI. This case demonstrated the importance of molecular cytology in the era of targeted therapy.     

The Role of MET Receptor Tyrosine Kinase in Non‐Small Cell Lung Cancer and Clinical Development of Targeted Anti‐MET Agents

A better understanding of the pathophysiology and evolution of non‐small cell lung cancer (NSCLC) has identified a number of molecular targets and spurred development of novel targeted therapeutic agents. The MET receptor tyrosine kinase and its ligand hepatocyte growth factor (HGF) are implicated in tumor cell proliferation, migration, invasion, and angiogenesis in a broad spectrum of human cancers, including NSCLC. Amplification of MET has been reported in approximately 5%–22% of lung tumors with acquired resistance to small‐molecule inhibitors of the epidermal growth factor receptor (EGFR). Resistance to EGFR inhibitors is likely mediated through downstream activation of the phosphoinositide 3‐kinase /AKT pathway. Simultaneous treatment of resistant tumors with a MET inhibitor plus an EGFR inhibitor can abrogate activation of downstream effectors of cell growth, proliferation, and survival, thereby overcoming acquired resistance to EGFR inhibitors. Development and preclinical testing of multiple agents targeting the HGF–MET pathway, including monoclonal antibodies targeting HGF or the MET receptor and small‐molecule inhibitors of the MET tyrosine kinase, have confirmed the crucial role of this pathway in NSCLC. Several agents are now in phase III clinical development for the treatment of NSCLC. This review summarizes the role of MET in the pathophysiology of NSCLC and in acquired resistance to EGFR inhibitors and provides an update on progress in the clinical development of inhibitors of MET for treatment of NSCLC.     

Enhanced gefitinib‐induced repression of the epidermal growth factor receptor pathway by ataxia telangiectasia‐mutated kinase inhibition in non‐small‐cell lung cancer cells

The epidermal growth factor receptor (EGFR) tyrosine kinase signaling pathways regulate cellular activities. The EGFR tyrosine kinase inhibitors (EGFR‐TKIs) repress the EGFR pathway constitutively activated by somatic EGFR gene mutations and have drastically improved the prognosis of non‐small‐cell lung cancer (NSCLC) patients. However, some problems, including resistance, remain to be solved. Recently, combination therapy with EGFR‐TKIs and cytotoxic agents has been shown to improve the prognosis of NSCLC patients. To enhance the anticancer effects of EGFR‐TKIs, we examined the cross‐talk of the EGFR pathways with ataxia telangiectasia‐mutated (ATM) signaling pathways. ATM is a key protein kinase in the DNA damage response and is known to phosphorylate Akt, an EGFR downstream factor. We found that the combination of an ATM inhibitor, KU55933, and an EGFR‐TKI, gefitinib, resulted in synergistic cell growth inhibition and induction of apoptosis in NSCLC cell lines carrying the sensitive EGFR mutation. We also found that KU55933 enhanced the gefitinib‐dependent repression of the phosphorylation of EGFR and/or its downstream factors. ATM inhibition may facilitate the gefitinib‐dependent repression of the phosphorylation of EGFR and/or its downstream factors, to exert anticancer effects against NSCLC cells with the sensitive EGFR mutation.     

非小细胞肺癌中EGFR基因状态的检测对EGFR-TKIs疗效的预测价值

近几年,表皮生长因子受体(epidermal growth factor receptor,EGFR)是肿瘤学药物研发的一个重要靶点。EGFR的小分子抑制剂(tyrosine kinase inhibitors,TKIs)成为目前非小细胞肺癌(non-small cell lung cancer,NSCLC)靶向治疗的热点。临床研究表明,EGFR-TKIs的临床疗效存在明显的个体差异,EGFR分子的存在状态影响TKI的疗效。EGFR外显子突变、EGFR拷贝数增加的患者对TKI的疗效较好,而存在KRAS突变患者提示对TKI耐药。     

EGFR inhibitors in lung cancer

Targeted therapies inhibiting the epidermal growth factor receptor (EGFR) have been introduced in the treatment of patients with advanced non-small-cell lung cancer (NSCLC). Many inhibitors of the EGFR have been developed, targeting either the extracellular receptor domain with antibodies or the intracellular tyrosine kinase binding domain with small molecules. The tyrosine kinase inhibitor (TKI) gefitinib (Iressa) was the first targeted drug to be registered for the treatment of NSCLC after failure of chemotherapy. Given concurrently together with platinum combination chemotherapy both TKIs gefitinib and erlotinib (Tarceva) failed to increase activity. Sequential targeted therapy after chemotherapy is currently being investigated further. Studies with the monoclonal antibody cetuximab (Erbitux) combined with chemotherapy are ongoing. Side effects of the small molecules are mainly skin rash and diarrhea, whereas the antibodies do not give diarrhea. Selection of patients, based on molecular markers and patient characteristics, has become an important issue for the further development of these drugs, given there is activity in a relatively small group of patients with NSCLC. Newer drugs inhibiting more than one receptor pathway are being investigated in order to find activity in a broader group of patients.     

非小细胞肺癌脑转移治疗进展

非小细胞肺癌(NSCLC)脑转移的治疗方法包括激素、抗惊厥药物治疗、手术、放疗、化疗.近年来分子靶向治疗如表皮生长因子(EGFR)酪氨酸激酶抑制剂(TKI)成为NSCLC脑转移的新的治疗选择.     

阿帕替尼在非小细胞肺癌中的研究进展

非小细胞肺癌（non-small cell lung cancer, NSCLC）是我国死亡率最高的恶性肿瘤之一。近年来,NSCLC的治疗取得了长足的进步,众多新药的问世显著改善了晚期NSCLC患者的生存期。甲磺酸阿帕替尼是一种新型口服小分子血管内皮生长因子受体酪氨酸激酶抑制剂,目前已被批准用于胃癌的三线治疗。目前,大量研究证实阿帕替尼单药治疗晚期NSCLC也有较好效果。临床前研究提示,阿帕替尼还可改善化疗和EGFR TKI耐药,因此,阿帕替尼联合化疗或EGFR TKI治疗晚期NSCLC也进行了广泛的探索。现就阿帕替尼在NSCLC的基础及临床研究中的进展作一综述。     

Efficacy of immunotherapy targeting the neoantigen derived from epidermal growth factor receptor T790M/C797S mutation in non–small cell lung cancer

Lung cancer is the leading cause of cancer‐related deaths worldwide. Epidermal growth factor receptor‐tyrosine kinase inhibitors (EGFR‐TKI) often have good clinical activity against non–small cell lung cancer (NSCLC) with activating EGFR mutations. Osimertinib, which is a third‐generation EGFR‐TKI, has a clinical effect even on NSCLC harboring the threonine to methionine change at codon 790 of EGFR (EGFR T790M) mutation that causes TKI resistance. However, most NSCLC patients develop acquired resistance to osimertinib within approximately 1 year, and 40% of these patients have the EGFR T790M and cysteine to serine change at codon 797 (C797S) mutations. Therefore, there is an urgent need for the development of novel treatment strategies for NSCLC patients with the EGFR T790M/C797S mutation. In this study, we identified the EGFR T790M/C797S mutation‐derived peptide (790‐799) (MQLMPFGSLL) that binds the human leukocyte antigen (HLA)‐A*02:01, and successfully established EGFR T790M/C797S‐peptide‐specific CTL clones from human PBMC of HLA‐A2 healthy donors. One established CTL clone demonstrated adequate cytotoxicity against T2 cells pulsed with the EGFR T790M/C797S peptide. This CTL clone also had high reactivity against cancer cells that expressed an endogenous EGFR T790M/C797S peptide using an interferon‐γ (IFN‐γ) enzyme‐linked immunospot (ELISPOT) assay. In addition, we demonstrated using a mouse model that EGFR T790M/C797S peptide‐specific CTL were induced by EGFR T790M/C797S peptide vaccine in vivo. These findings suggest that an immunotherapy targeting a neoantigen derived from EGFR T790M/C797S mutation could be a useful novel therapeutic strategy for NSCLC patients with EGFR‐TKI resistance, especially those resistant to osimertinib.     

表皮生长因子受体基因20号外显子插入突变型非小细胞肺癌的治疗现状与展望

自表皮生长因子受体(EGFR)基因突变被发现以来,酪氨酸激酶抑制剂(TKI)的应用拉开了EGFR阳性非小细胞肺癌精准靶向治疗的序幕。携带EGFR基因常见的两类经典代表性突变,即第19号外显子框内缺失突变和第21号外显子L858R点突变(约占所有EGFR突变的90%)的非小细胞肺癌患者,接受TKI靶向治疗的临床获益远远优于传统化疗。EGFR基因第20号外显子插入突变却与众不同,在剩余10%EGFR少见基因突变中为最常见的类型,且这类突变中的绝大多数对目前临床应用的第一、二、三代TKI原发耐药,临床预后差。目前,国际上亦缺乏针对此突变的深入研究和临床治疗指南。文章介绍了EGFR基因20号外显子插入突变型非小细胞肺癌的发病机制、氨基酸序列亚型和治疗现状,探讨了此突变在目前肺癌治疗领域所面临的挑战与展望。     

Aberrant epidermal growth factor receptor signaling and enhanced sensitivity to EGFR inhibitors in lung cancer

Epidermal growth factor receptor (EGFR) is occasionally amplified and/or mutated in non-small cell lung cancer (NSCLC) and can be coexpressed with other members of the HER receptor family to form functional heterodimers. We therefore investigated lung cancer cell lines for alterations in EGFR gene copy number, enhanced expression of EGFR and other HER family members, and EGFR coding sequence mutations and correlated these findings with response to treatment with the EGFR inhibitors and the kinetics of ligand-induced signaling. We show here that somatic deletions in the tyrosine kinase domain of EGFR were associated with increased EGFR gene copy number in NSCLC. Treatment with the specific EGFR tyrosine kinase inhibitors (TKI) gefitinib or erlotinib or the EGFR inhibitory antibody cetuximab induced apoptosis of HCC827, a NSCLC cell line with EGFR gene amplification and an exon 19 deletion. H1819, a NSCLC cell line that expresses high levels of EGFR, ErbB2, and ErbB3 but has wild-type EGFR, showed intermediate sensitivity to TKIs. In both cell lines, ligand-induced receptor tyrosine phosphorylation was delayed and prolonged and AKT was constitutively phosphorylated (but remained inhibitable by EGFR TKI). Thus, in addition to EGFR mutations, other factors in NSCLC cells, such as high expression of ErbB family members, may constitutively activate AKT and sensitize cells to EGFR inhibitors.     

The insulin‐like growth factor 1 receptor causes acquired resistance to erlotinib in lung cancer cells with the wild‐type epidermal growth factor receptor

Epidermal growth factor receptor (EGFR)‐tyrosine kinase inhibitor (TKI) therapy often provides a dramatic response in lung cancer patients with EGFR mutations. In addition, moderate clinical efficacy of the EGFR‐TKI, erlotinib, has been shown in lung cancer patients with the wild‐type EGFR. Numerous molecular mechanisms that cause acquired resistance to EGFR‐TKIs have been identified in lung cancers with the EGFR mutations; however, few have been reported in lung cancers with the wild‐type EGFR. We used H358 lung adenocarcinoma cells lacking EGFR mutations that showed modest sensitivity to erlotinib. The H358 cells acquired resistance to erlotinib via chronic exposure to the drug. The H358 erlotinib‐resistant (ER) cells do not have a secondary EGFR mutation, neither MET gene amplification nor PTEN downregulation; these have been identified in lung cancers with the EGFR mutations. From comprehensive screening of receptor tyrosine kinase phosphorylation, we observed increased phosphorylation of insulin‐like growth factor 1 receptor (IGF1R) in H358ER cells compared with parental H358 cells. H358ER cells responded to combined therapy with erlotinib and NVP‐AEW541, an IGF1R‐TKI. Our results indicate that IGF1R activation is a molecular mechanism that confers acquired resistance to erlotinib in lung cancers with the wild‐type EGFR.     

Acquired MET D1228N Mutations Mediate Crizotinib Resistance in Lung Adenocarcinoma with ROS1 Fusion: A Case Report

Patients with non‐small cell lung cancer (NSCLC) containing ROS1 fusions can have a marked response to the ROS1‐targeted tyrosine kinase inhibitors (TKIs), such as crizotinib. Common resistance mechanisms of ROS1‐fusion targeted therapy are acquired mutations in ROS1. Along with the use of next‐generation sequencing in the clinical management of patients with NSCLC during sequential targeted therapy, many mechanisms of acquired resistance have been discovered in patients with activated tyrosine kinase receptors. Besides acquired resistance mutations, bypass mechanisms of resistance to epidermal growth factor receptor (EGFR)‐TKI treatment are common in patients with EGFR mutations. Here we describe a patient with metastatic lung adenocarcinoma with CD74‐ROS1 fusion who initially responded to crizotinib and then developed resistance by the acquired mutation of D1228N in the MET kinase domain, which showed short‐term disease control for cabozantinib.Key Points

• The D1228N point mutation of MET is an acquired mutation for crizotinib resistance.
• The patient obtained short‐term clinical benefit from cabozantinib therapy after resistance to crizotinib.
• The clinical use of next‐generation sequencing could maximize the benefits of precision medicine in patients with cancer.