Erlotinib: a new therapeutic approach for non-small cell lung cancer

Although treatment with cytotoxic agents has produced modest survival improvement in patients with stage III and IV non-small cell lung cancer (NSCLC), it appears that a plateau has been reached with currently available chemotherapeutic regimens. Increasing knowledge regarding the properties of malignant neoplasms has identified a number of potential therapeutic targets. The epidermal growth factor receptor (EGFR) is one of these targets. Preclinical models have revealed that tumour growth can be inhibited by monoclonal antibodies directed against EGFR and EGFR-specific tyrosine kinase inhibitors. Erlotinib (Tarceva?; OSI Pharmaceuticals, Genentech and Roche), a quinazoline derivative with good oral absorption, is one of several EGFR tyrosine kinases that has been studied in clinical trials. In a Phase I study, mild diarrhoea and mild rash were the most common toxicities. At a dose of 200 mg/day, diarrhoea was the dose-limiting toxicity. The observation that EGFR overexpression is relatively common in NSCLC led to a Phase II trial of erlotinib at the maximum-tolerated dose (150 mg/day) in previously treated NSCLC patients. Erlotinib produced a 12% response rate and there was no apparent relationship between response and tumour EGFR levels. More recent reports suggest that patients who develop a rash have higher responses. Based on its single agent activity, erlotinib has been evaluated in two Phase III trials which compared erlotinib plus chemotherapy to chemotherapy alone in previously untreated NSCLC patients. Erlotinib has also been compared to placebo in a Phase III trial which was limited to advanced stage NSCLC patients whose disease had progressed after two previous chemotherapy regimens. The optimum use of erlotinib in NSCLC will be determined by the results of the completed and future Phase III trials.     

Erlotinib: a new therapeutic approach for non-small cell lung cancer

Although treatment with cytotoxic agents has produced modest survival improvement in patients with stage III and IV non-small cell lung cancer (NSCLC), it appears that a plateau has been reached with currently available chemotherapeutic regimens. Increasing knowledge regarding the properties of malignant neoplasms has identified a number of potential therapeutic targets. The epidermal growth factor receptor (EGFR) is one of these targets. Preclinical models have revealed that tumour growth can be inhibited by monoclonal antibodies directed against EGFR and EGFR-specific tyrosine kinase inhibitors. Erlotinib (Tarceva trade mark; OSI Pharmaceuticals, Genentech and Roche), a quinazoline derivative with good oral absorption, is one of several EGFR tyrosine kinases that has been studied in clinical trials. In a Phase I study, mild diarrhoea and mild rash were the most common toxicities. At a dose of 200 mg/day, diarrhoea was the dose-limiting toxicity. The observation that EGFR overexpression is relatively common in NSCLC led to a Phase II trial of erlotinib at the maximum-tolerated dose (150 mg/day) in previously treated NSCLC patients. Erlotinib produced a 12% response rate and there was no apparent relationship between response and tumour EGFR levels. More recent reports suggest that patients who develop a rash have higher responses. Based on its single agent activity, erlotinib has been evaluated in two Phase III trials which compared erlotinib plus chemotherapy to chemotherapy alone in previously untreated NSCLC patients. Erlotinib has also been compared to placebo in a Phase III trial which was limited to advanced stage NSCLC patients whose disease had progressed after two previous chemotherapy regimens. The optimum use of erlotinib in NSCLC will be determined by the results of the completed and future Phase III trials.     

Erlotinib in non-small-cell lung cancer

Epidermal growth factor receptor (EGFR) plays an essential role in normal cell growth and differentiation, and is involved in tumour proliferation and survival. EGFR overexpression is a common feature in solid malignancies, including non-small-cell lung cancer (NSCLC), and is associated with poor clinical prognosis. Erlotinib is a small-molecule inhibitor of EGFR tyrosine kinase, showing a significant improvement in median survival, quality of life and related symptoms in an unselected population of advanced NSCLC patients in the second- or third-line setting. Erlotinib is well tolerated (with common toxicities including rash and diarrhoea) when administered at a standard oral daily dose of 150 mg. Further investigations are ongoing to contribute to our understanding of the role of erlotinib in NSCLC treatment.     

Erlotinib in non-small-cell lung cancer

Epidermal growth factor receptor (EGFR) plays an essential role in normal cell growth and differentiation, and is involved in tumour proliferation and survival. EGFR overexpression is a common feature in solid malignancies, including non-small-cell lung cancer (NSCLC), and is associated with poor clinical prognosis. Erlotinib is a small-molecule inhibitor of EGFR tyrosine kinase, showing a significant improvement in median survival, quality of life and related symptoms in an unselected population of advanced NSCLC patients in the second- or third-line setting. Erlotinib is well tolerated (with common toxicities including rash and diarrhoea) when administered at a standard oral daily dose of 150 mg. Further investigations are ongoing to contribute to our understanding of the role of erlotinib in NSCLC treatment.     

Rational combination of targeted therapies as a strategy to overcome the mechanisms of resistance to inhibitors of EGFR signaling

The epidermal growth factor receptor (EGFR) has been widely used as a target for novel anticancer agents, such as blocking antibodies and small molecular weight tyrosine kinase compounds. In spite of recent advances in cancer cell biology, leading to the introduction of clinically active new drugs, such as cetuximab, panitumumab and erlotinib, unfortunately disease control remains unsuccessful due to the presence of constitutive resistance to EGFR inhibitors in most patients and the development of acquired resistance in the responders. A large number of molecular abnormalities in tumor cells seem to partly contribute to their resistance to anti-EGFR therapy: increased angiogenesis, constitutive activation of downstream mediators, overexpression of other tyrosine kinase receptors. Moreover, some mutations in the EGFR receptor kinase domain seem to play a crucial role in determining the sensitivity of cancer cells to specific inhibitors by altering the conformation of the receptor and its activity. The development of rational combinations of anticancer agents and EGFR inhibitors, able to exert synergistic cytotoxic interactions, has been widely accepted and used in both preclinical and clinical studies. Although the failure of large clinical trial based on empirical combination of anti-EGFR and classic chemotherapeutic agents, several preclinical data seems to support the hypothesis that combining EGFR inhibitors and other novel agents could efficiently inhibit tumor growth and overcome intrinsic resistance to a single-agent based therapy. This review focuses on the role of complementary signalling pathways in the development of resistance to EGFR targeting agents and the rationale to combine novel inhibitors as anticancer therapy.     

Clinical experience with erlotinib in non-small-cell lung cancer

Lung cancer is the leading cause of cancer death worldwide. Despite the introduction of more- effective chemotherapeutic agents, it appears that a survival plateau has been reached, so new treatment strategies are clearly needed. One innovative therapeutic cancer strategy is the introduction of biological agents that target specific intracellular pathways related to the distinctive properties of cancer cells. Among these agents, epidermal growth factor receptor (EGFR)-targeting agents have received particular attention in lung cancer. Numerous EGFR blockers have been evaluated, including monoclonal antibodies to the receptor and small-molecule tyrosine kinase inhibitors. The present review focuses on the tyrosine kinase inhibitor erlotinib. Preclinical studies have shown that erlotinib blocks the growth of human non-small-cell lung cancer (NSCLC) cell lines in vitro by inhibiting the receptor and the downstream protein phosphorylation. In a randomized study conducted by the National Cancer Institute of Canada (BR.21) in second- and third-line NSCLC treatment, erlotinib significantly prolonged overall survival and decreased symptoms compared with placebo. A crucial aspect of the clinical development of molecular-targeted therapies is to understand which patients will obtain clinical benefit from their use. Sensitivity to erlotinib has been associated with EGFR mutations, most commonly deletions of four to six amino acids in exon 19 or a point mutation (L858R) in exon 21. Increased EGFR gene copy number has also been pointed out as a good predictive marker for erlotinib response. Intense research activity is ongoing to validate known predictive markers and to discover new tools which maximize clinical benefit using erlotinib. However, there is no conclusive evidence, as yet, linking response to survival.     

Targeting EGFR in pancreatic cancer treatment

The prognosis of patients with pancreatic cancer is extremely poor, and current systemic therapies provide marginal survival benefits for treated patients. The era of targeted therapies has offered a new avenue to search for potentially more effective strategies. Epidermal growth factor receptor (EGFR) is a member of the erbB/human epidermal growth factor receptor family of tyrosine kinases, which includes erbB2/HER2, erbB3/HER3 and erbB4/HER4. Epidermal growth factor receptor overexpression may be detected in up to 90% of pancreatic tumors. Two pharmacologic approaches have been successfully used to inhibit epidermal growth factor receptor function in cancer treatment: neutralizing monoclonal antibodies and small molecule tyrosine inhibitors. The randomized trials studying the addition of EGFR targeted agents to gemcitabine compared with gemcitabine alone have been disappointing, although results with the EGFR tyrosine kinase inhibitor erlotinib were statistically significant but clinically of marginal benefit. In this article, we review the epidermal growth factor receptor signaling network in pancreatic cancer, the strategies to increase the effectiveness of epidermal growth factor receptor inhibitors, and the clinical trials of these inhibitors in pancreatic cancer.     

Role of erlotinib in the treatment of non-small cell lung cancer: clinical outcomes in wild-type epidermal growth factor receptor patients

Erlotinib is an orally administered small molecule inhibitor of epidermal growth factor receptor (EGFR) tyrosine kinase. Erlotinib at the standard oral daily dose of 150 mg is approved for the treatment of unselected chemorefractory advanced non-small cell lung cancer patients as well as maintenance therapy after first-line chemotherapy. The European Medicines Agency has recently also approved erlotinib as the first-line therapy in patients with EGFR mutations. Although recent studies have identified higher response rates and improved survival with erlotinib in a subset of patients with EGFR mutations, the survival benefit from single agent erlotinib in chemorefractory patients and in the maintenance setting is well observed in EGFR wild-type patients. The role of single agent erlotinib in the first-line setting in special subsets of EGFR wild-type patients (elderly, poor performance status, non-smokers) needs to be further determined. The combination of erlotinib with other targeted therapies has shown promising results and warrants further studies in EGFR wild-type patients.     

Erlotinib in glioblastoma: lost in translation?

Glioblastoma represents the most common primary brain tumor in adults. Despite improvements of multimodal therapy, the prognosis of this disease remains unfavorable. Thus, great efforts have been made to identify therapeutic agents directed against those specific molecular targets whose presence was shown to be associated with worse clinical outcomes. The epidermal growth factor receptor (HER1/EGFR) has been identified as one such target, and different compounds were developed to inhibit HER1/EGFR and/ or its mutant form, EGFRvIII. However, clinical trials did not confirm the initial enthusiasm conveyed by promising results from experimental studies. Therefore, a therapeutic approach directed at inhibiting solely HER1/EGFR does not seem to translate into a clinical benefit. This review discusses the current therapeutic situation in the setting of glioblastoma while putting the spotlight on erlotinib, a HER1/EGFR-targeted small molecule tyrosine kinase inhibitor.     

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.     

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.     

非小细胞肺癌靶向治疗新药——厄洛替尼

厄洛替尼是一种口服、高选择性、可逆的表皮生长因子受体(EGFR)酪氨酸激酶(TK)抑制剂,它通过抑制EGFR-TK的自磷酸化反应,抑制信号转导,从而达到抑制肿瘤生长作用。一项Ⅲ期安慰剂对照临床研究结果表明,厄洛替尼每日口服150 mg单药治疗,可显著延长晚期复发性非小细胞肺癌(NSCLC)病人的生存期、延缓疾病进展和症状恶化,且耐受性较好,最常见的不良反应为皮疹和腹泻。本文对厄洛替尼的药动学和药效学特性、临床疗效和药物相互作用以及难治性晚期NSCLC病人的耐受性等作一综述。     

Optimal management of patients with non-small cell lung cancer and epidermal growth factor receptor mutations

In recent years, the epidermal growth factor receptor (EGFR) tyrosine kinase inhibitors (TKIs), gefitinib and erlotinib, which have promising activity and a favourable toxicity profile, have been used in the management of advanced non-small cell lung cancer (NSCLC). The knowledge that EGFR-activating mutations confer sensitivity to EGFR TKIs has led to the design and analysis of phase II and III studies of gefitinib or erlotinib treatment in various clinical scenarios. We review the important NSCLC clinical trials of the efficacy of EGFR TKIs in the context of EGFR-activating mutations. In all phase II single-arm studies or phase III randomized comparative studies, EGFR TKIs as monotherapy were superior to combination chemotherapy in terms of response rate and progression-free survival in patients with activating EGFR mutations. EGFR TKIs have contributed to the superior overall survival time in NSCLC patients with EGFR mutations compared with those patients without EGFR mutations. The results of these studies have led to a paradigm shift in the treatment of patients with advanced NSCLC. NSCLC with EGFR mutations constitutes a new entity requiring different personalized treatment strategies.     

Epidermal growth factor receptor and signal transduction: potential targets for anti-cancer therapy

Agents targeting the epidermal growth factor receptor (EGFR) pathway hold particular promise for the treatment of patients with advanced disease, for whom standard chemotherapy is generally palliative. Expression of EGFR on numerous types of solid tumors, and the association of EGFR activation with tumorigenic processes including proliferation, anti-apoptosis and metastatic spread, make this pathway a particularly compelling target for rational drug design. The two classes of anti-EGFR agents in late-stage clinical testing include antibodies directed toward the extracellular EGFR domain (cetuximab, panitumumab) and small molecule tyrosine kinase inhibitors (gefitinib, erlotinib), which inactivate the receptor enzyme activity. However, important issues remain to be addressed. These include the development of appropriate predictive markers for response, such as improved tests for EGFR activity, correlation of rash with response and potential pharmacogenomic approaches; the sequencing and combination of these agents with chemotherapy and irradiation; and the possible role of these agents in the treatment of patients with earlier stage disease.     

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.     

Review. EGFR mutations in non-small cell lung cancer--clinical implications

The epidermal growth factor receptor (EGFR) family members seem to play a critical role in lung tumourigenesis and are overexpressed in 40-80% of non-small cell lung carcinoma (NSCLC) tumours. EGFR activation results in a series of downstream signaling events that mediate cancer cell growth, proliferation, motility, adhesion, invasion, apoptosis inhibition and metastasis as well as resistance to chemotherapy. Therefore, EGFR inhibitors seem to be an effective therapy for some patients with previously treated NSCLC. A thorough investigation of EGFR, its major signaling pathways, its identification and biology in NSCLC and the responsiveness to gefitinib, erlotinib and cetuximab in connection to EGFR mutations as well as the possible mechanisms of resistance to tyrosine kinase inhibitors is the scope of this review.     

EGFR基因突变与肿瘤靶向治疗

表皮生长因子受体(epidermal growth factor receptor,EGFR)属于受体酪氨酸激酶超家族,在多种恶性肿瘤中表达。配体与EGFR结合诱导形成二聚体和构象变化,活化酪氨酸激酶及信号转导途径,产生细胞增殖、侵润、转移及抗凋亡等效应。EGFR酪氨酸激酶抑制剂(tyrosine kinase inhibitors,TKIs)类靶向药物,如吉非替尼和厄洛替尼等已应用于临床。临床研究显示仅10%~30%患者对TKIs敏感,部分位于EGFR激酶结构域的活化突变与药物敏感性相关。检测EGFR基因突变有助于预测对药物敏感性和提高疗效。随着治疗绝大多数敏感的患者获得继发耐药性,其中约半数有继发突变T790M,降低药物对靶分子的亲和力,其他许多位于EGFR下游信号途径或旁激活途径的分子也参与耐药形成。因此,未来个体化用药和准确预测敏感性,不仅仅要分析EGFR基因,而且要综合考虑下游和其他信号途径的基因,如PI3K,K-RAS,BRAF,MET和PTEN等。     

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.     

A review of erlotinib and its clinical use

Erlotinib is an orally available, reversible tyrosine kinase inhibitor of the epidermal growth factor receptor. Encouraging activity as a single agent and in combination with other targeted agents has been demonstrated in Phase II trials in many tumour types. Erlotinib has an established role in the treatment of advanced, refractory non-small cell lung cancer-based on a pivotal trial demonstrating a survival advantage over best supportive care. In a Phase III trial, the addition of erlotinib to gemcitabine improved survival in advanced pancreatic cancer. The toxicity profile of erlotinib includes diarrhoea and rash, with no haematological side effects. Predictive factors for response include the presence of a rash, epidermal growth factor receptor expression and mutation status. This article reviews the current clinical status of erlotinib.     

表皮生长因子受体抑制剂相关性皮肤毒性的研究进展

表皮生长因子受体抑制剂包括小分子酪氨酸激酶抑制剂及单抗类,在肺癌、结直肠癌等肿瘤的分子靶向治疗中起着重要作用。其中小分子酪氨酸激酶抑制剂包括吉非替尼、厄洛替尼、埃克替尼等,单抗类包括西妥昔单抗、帕尼单抗等。以痤疮样皮疹为代表的皮肤毒性是表皮生长因子受体抑制剂使用后最常见的不良反应,严重的皮肤毒性导致药物剂量减少与治疗的中断,影响药物的抗肿瘤疗效。但目前临床对于这一类皮肤毒性仍没有十分有效的处理方法。已有临床试验涉及的处理方法包括口服四环素类药物、局部应用维生素K乳剂、局部应用他克莫司、防晒霜以及表皮生长因子凝胶等。本文综述了此类皮疹的发生机制、治疗皮疹药物的临床试验结果及已有的专家共识或指南,以期为这一类不良反应的处理提供临床思路。