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.     

Small molecules with EGFR-TK inhibitor activity

Specific and reversible EGFR tyrosine kinase inhibitors (TKI) such as gefitinib and erlotinib are clinically active in advanced or metastatic NSCLC and both are approved in various countries for the treatment of patients that failed prior chemotherapy. Erlotinib has also prolonged survival in pancreatic cancer patients when added to gemcitabine and regulatory approval in this disease is being sought. Additional promising activity has been seen in other tumor types, such as ovarian cancer or head and neck malignancies, and phase III trials in these malignancies are ongoing or planned. Despite these successes, these agents have exhibited anecdotal or modest activity when used as single agents in unselected patients with various other tumor types. We have learned that the clinical development of these agents is far from simple and we need to better understand biological and clinical criteria for patient selection and how to best use the different available agents. The recent discovery of EGFR mutations and the potential identification of other markers that might predict patient response could help to optimize the use of these agents in the future. Irreversible EGFR inhibitors, dual EGF/HER2 and pan-ErbB receptor inhibitors may have greater antitumor activity although the tolerance of these compounds compared to specific EGFR TKIs needs further characterization. HER2 specific TKIs are also in development. Lapatinib, a dual EGFR/HER2 TK inhibitors, is particularly promising in breast cancer. Newer agents, such as BMS-599626, have recently entered into the clinic. In addition to the use of these agents as single agents, many clinical studies are addressing the role of combining them with hormonal agents, biological agents or chemotherapy.     

Safety of gefitinib in non-small cell lung cancer treatment

ABSTRACT

Introduction: The development of EGFR TKI and the subsequent identification of activating EGFR mutations have dramatically changed how NSCLC is treated. With its recent approval by the US Food and Drug Administration, gefitinib adds to the list of recommended first-line treatments for lung cancer harboring EGFR mutations, which hitherto includes erlotinib and afatinib.

Areas covered: This review summarizes the pharmacological property, clinical efficacy, and safety of gefitinib in major clinical trials and post-marketing studies.

Expert opinion: Gefitinib is a well-tolerated treatment for advanced NSCLC. The most common adverse events are skin reaction and diarrhea, both of which are generally mild, noncumulative, and manageable. Other side effects such as interstitial lung disease and liver toxicity are less common but can be serious. Which EGFR TKI is the preferred first-line treatment is a matter of debate. Gefitinib and erlotinib have comparable efficacy, whereas afatinib may exert superior clinical activity over gefitinib. In terms of the most common toxicities of skin reaction and diarrhea, gefitinib may be the most tolerable of the three. Hence, despite being the earliest EGFR TKI developed, gefitinib continues to be one of the first-line treatments for advanced EGFR-mutated NSCLC, especially when skin and gastrointestinal toxicity is a concern.     

Epidermal growth factor receptor inhibitors: an update on their development as cancer therapeutics

Therapeutic agents targeting the epidermal growth factor receptor (EGFR) have recently been approved for use in patients based on the results of large-scale phase II studies involving patients with advanced refractory non-small-cell lung cancer (NSCLC). Disappointingly, results from phase III trials of gefitinib in combination with standard chemotherapy regimens for the treatment of NSCLC were negative. While results from phase III trials with other agents such as erlotinib and cetuximab will be reported in the next 12 to 18 months, the early results raise a number of questions regarding the development of these agents, including patient selection (e.g., disease, stage, prior therapy, EGFR or other biomarker expression) and combinations with standard treatment regimens as well as hormonal agents, radiation or other novel agents which will require further elucidation. Early data suggest a number of potential roles for these agents in the modulation of resistance and in combination with other inhibitors of signal transduction.     

酪氨酸激酶抑制剂(吉非替尼、厄洛替尼、阿法替尼和奥希替尼)一线治疗表皮生长因子受体突变的晚期非小细胞肺癌的成本-效果分析

吉非替尼、厄洛替尼、阿法替尼和奥希替尼已被推荐为表皮生长因子受体突变的晚期非小细胞肺癌的一线治疗药物,但同时比较这四种酪氨酸激酶抑制剂在中国的经济性目前尚无研究.本研究旨在评价吉非替尼、厄洛替尼、阿法替尼和奥希替尼一线治疗表皮生长因子受体突变的晚期非小细胞肺癌的成本-效果性.通过构建马尔科夫模型,从中国医疗系统角度评价...     

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

Non-small cell lung cancer (NSCLC) is the leading cause of cancer-related death in both men and women. Despite the introduction of the newer cytotoxic agents in NSCLC treatment during the last decade the survival rates of patients have reached a plateau. New strategies are clearly needed to improve treatment outcomes. Epidermal growth factor receptor (EGFR) has a key role in cancer development and progression and has been recognised as a target of increasing importance in NSCLC. Gefitinib, erlotinib and cetuximab are EGFR-targeting agents that are being extensively evaluated in NSCLC. EGFR inhibitors demonstrate significant clinical activity in ~ 10 – 20% of pretreated NSCLC patients. Somatic mutations in the kinase domain of the receptor have been shown to be associated with enhanced sensitivity to EGFR inhibitors. However, four large Phase III randomised, placebo-controlled trials of gefitinib and erlotinib in combination with standard platinum-based first-line chemotherapy failed to show any survival benefit in patients receiving the study drugs. Possible reasons include patient selection, drug scheduling, trial design or other factors. Active research is ongoing to improve the efficacy of EGFR inhibitors as monotherapy or in combination with other treatment modalities.     

The role of EGFR tyrosine kinase inhibitors in the first-line treatment of advanced non small cell lung cancer patients harboring EGFR mutation

Lung cancer continues to be the leading cause of cancer death worldwide. Among lung cancers, 80% are classified as nonsmall- cell lung cancer (NSCLC) and are mostly diagnosed at an advanced stage (either locally advanced or metastatic disease). In the last years, the discovery of the pivotal role in tumorigenesis of the Epidermal Growth Factor Receptor (EGFR) has provided a new class of targeted therapeutic agents: the EGFR tyrosine kinase inhibitors (EGFR-TKIs). Since the first reports of an association between somatic mutations in EGFR exons 19 and 21 and response to EGFR-TKIs, treatment of advanced NSCLC has changed dramatically. Histologic profile, clinical characteristics, and mutational profile of lung carcinoma have all been reported as predictive factors of response to EGFR-TKIs and other targeted therapies. In advanced NSCLC patients harboring EGFR mutations, the use of EGFR TKIs in first-line treatment has provided an unusually large progression-free survival (PFS) benefit with a negligible toxicity when compared with cytotoxic chemotherapy in phase III randomized trials. Considering the findings regarding the excellent benefit and better safety profile of EGFR TKIs in EGFR mutation positive patients, these targeted therapeutic agents can be now considered as first-line treatment in this setting of patients. This review will discuss the new evidences in the role of EGFR-TKIs in the first-line treatment of advanced NSCLC and their implication in the current clinical decision-making.     

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

Non-small cell lung cancer (NSCLC) is the leading cause of cancer-related death in both men and women. Despite the introduction of the newer cytotoxic agents in NSCLC treatment during the last decade the survival rates of patients have reached a plateau. New strategies are clearly needed to improve treatment outcomes. Epidermal growth factor receptor (EGFR) has a key role in cancer development and progression and has been recognised as a target of increasing importance in NSCLC. Gefitinib, erlotinib and cetuximab are EGFR-targeting agents that are being extensively evaluated in NSCLC. EGFR inhibitors demonstrate significant clinical activity in approximately 10-20% of pretreated NSCLC patients. Somatic mutations in the kinase domain of the receptor have been shown to be associated with enhanced sensitivity to EGFR inhibitors. However, four large Phase III randomised, placebo-controlled trials of gefitinib and erlotinib in combination with standard platinum-based first-line chemotherapy failed to show any survival benefit in patients receiving the study drugs. Possible reasons include patient selection, drug scheduling, trial design or other factors. Active research is ongoing to improve the efficacy of EGFR inhibitors as monotherapy or in combination with other treatment modalities.     

Chronicles of EGFR Tyrosine Kinase Inhibitors: Targeting EGFR C797S Containing Triple Mutations

Epidermal growth factor receptor (EGFR) is a receptor tyrosine kinase widely expressed in many cancers such as non-small cell lung cancer (NSCLC), pancreatic cancer, breast cancer, and head and neck cancer. Mutations such as L858R in exon 21, exon 19 truncation (Del19), exon 20 insertions, and others are responsible for aberrant activation of EGFR in NSCLC. First-generation EGFR tyrosine kinase inhibitors (TKIs) such as gefitinib and erlotinib have clinical benefits for EGFR-sensitive (L858R and Del19) NSCLC patients. However, after 10-12 months of treatment with these inhibitors, a secondary T790M mutation at the gatekeeper position in the kinase domain of EGFR was identified, which limited the clinical benefits. Second-generation EGFR irreversible inhibitors (afatinib and dacomitinib) were developed to overcome this T790M mutation. However, their lack of selectivity toward wild-type EGFR compromised their clinical benefits due to serious adverse events. Recently developed third-generation irreversible EGFR TKIs (osimertinib and lazertinib) are selective toward driving mutations and the T790M mutation, while sparing wild-type EGFR activity. The latest studies have concluded that their efficacy was also compromised by additional acquired mutations, including C797S, the key residue cysteine that forms covalent bonds with irreversible inhibitors. Because second- and third-generation EGFR TKIs are irreversible inhibitors, they are not effective against C797S containing EGFR triple mutations (Del19/T790M/C797S and L858R/T790M/C797S). Therefore, there is an urgent unmet medical need to develop next-generation EGFR TKIs that selectively inhibit EGFR triple mutations via a non-irreversible mechanism.     

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.     

Prognostic and predictive value of K-RAS mutations in non-small cell lung cancer

Non-small cell lung cancer (NSCLC) is a heterogeneous disease, caused by the presence of different clinically relevant molecular subtypes. Genetic mutations are emerging as potential biomarkers of response and treatment selection in patients with NSCLC. Over the past few years, activating mutations of epidermal growth factor receptor (EGFR) have been recognized as the most important predictor of response to EGFR tyrosine kinase inhibitors (TKIs) such as gefitinib and erlotinib and also as a favourable prognostic factor. The RAS genes, including H-RAS, K-RAS and N-RAS, encode a family of proteins regulating cell growth, differentiation and apoptosis. Mutations in the K-RAS gene, mainly in codons 12 and 13, have been found in 20-30% of NSCLC tumor samples and occur most commonly, but not exclusively, in adenocarcinoma histology and in heavy smokers. In NSCLC, the presence of K-RAS mutations has generally been considered to be associated with worse prognosis and resistance to systemic therapy in the adjuvant as well as the metastatic setting. In early stage NSCLC, the prognostic role of K-RAS mutations has been evaluated in several studies without definitive conclusion. On the other hand, in advanced NSCLC, the presence of K-RAS mutations identifies a subgroup of patients who do not respond to EGFR-TKI therapy but, at the same time, a positive survival effect from EGFR-TKIs cannot be excluded in these patients. Similarly, K-RAS mutational status does not predict benefit from the anti-EGFR monoclonal antibody cetuximab, highlighting the biological difference between lung cancer and colorectal cancer. As a result of the lack of conclusive data, K-RAS mutations do not represent a validated biomarker for the negative selection of patients who are candidates for anti-EGFR therapy. The aim of this article is to review and discuss the data on the prognostic and predictive value of K-RAS mutations in NSCLC.     

Afatinib for the first-line treatment of patients with metastatic EGFR-positive NSCLC: a look at the data

Introduction: Epidermal growth factor receptor (EGFR) mutations are detected in about 10–15% of Caucasian and 30–40% of Asian patients with advanced or metastatic non-small-cell lung cancer (NSCLC). In patients harbouring EGFR mutations, the treatment with different available EGFR tyrosine kinase inhibitors (TKIs) showed to be more effective and safe than platinum-based chemotherapy regimens.

Areas covered: The current evidences about the role of afatinib for patients with EGFR-positive NSCLC are reviewed and discussed. We report a review based on a MEDLINE/PubMed, searched for randomized phase II or III trials evaluating afatinib in EGFR-positive NSCLC.

Expert commentary: Afatinib is the third EGFR TKI approved for the treatment of NSCLC harbouring EGFR mutations, showing high efficacy in this setting of patients.     

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.     

Role of EGFR inhibitors in the treatment of central nervous system metastases from non-small cell lung cancer

Brain metastases (BM) are a common occurrence in patients with non-small cell lung cancer (NSCLC). Standard therapy options include whole brain radiotherapy and, in selected patients, surgery or stereotactic radiosurgery. The role of systemic treatment is controversial. There is a strong clinical rationale for the use of targeted therapies, because patients often have a poor performance status, and are not candidates for cytotoxic chemotherapy or radiotherapy, yet treatment is required to improve the extra-cranial disease. The efficacy of epidermal growth factor receptor (EGFR) inhibitors in the treatment of patients with BM from NSCLC has been reported mainly in case reports or small retrospective case series, with only a few prospective trials. Current evidence suggests that the use of EGFR tyrosine kinase inhibitors (TKIs) gefitinib and erlotinib should be considered in patients with asymptomatic CNS involvement, when clinical characteristics suggest a high likelihood of response; these characteristics are adenocarcinoma histology, never-smoker status, female gender and East Asian ethnicity. Upfront therapy with EGFR TKIs should be strongly considered in asymptomatic patients harboring activating EGFR mutations. In symptomatic BM, radiotherapy (RT) remains the standard treatment. Based on currently available data, treatment with concurrent RT and EGFR TKIs should be investigated in experimental trials only.     

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.     

Successful treatment with erlotinib after gefitinib-induced interstitial lung disease: a case report and literature review

Gefitinib and erlotinib, epidermal growth factor receptor (EGFR) tyrosine kinase inhibitors (TKIs), are widely used anticancer drugs for patients with non-small cell lung cancer (NSCLC), especially for those with EGFR-activating mutations. Both agents are considered to be less toxic compared with cytotoxic drugs; however, serious adverse events including interstitial lung disease (ILD) which can be fatal occur rarely. After such an event, physicians avoid to use another TKI. In such cases, patients and physicians are forced to make difficult decisions or reluctantly choose TKI when there is no other option. Here we report a case of a patient with lung adenocarcinoma who showed good recovery from gefitinib-induced ILD by high-dose corticosteroid therapy. The patient was then administrated erlotinib as second-line chemotherapy and showed tumor shrinkage without ILD after 6 months of treatment. We discuss the common features of the cases in the previous documentations and ours which were successfully retreated with erlotinib after gefitinib-induced ILD had previously developed.     

Gefitinib in non-small cell lung cancer

Gefitinib (Iressa), an orally-active tyrosine kinase inhibitor of the epidermal growth factor receptor (EGFR), is the first approved molecular-targeted drug for the management of patients with advanced non-small cell lung cancer (NSCLC). Two Phase II trials (IDEAL [Iressa Dose Evaluation in Advanced Lung Cancer]-1 and -2), evaluated the efficacy of gefitinib in advanced NSCLC patients who received < or = 2 (IDEAL1) or > or = 2 (IDEAL2) previous chemotherapy regimens. The response rate and disease control rate in IDEAL1 and -2 was 18/12% and 54/42%, respectively. The median survival time and one-year survival rate in both studies were approximately 7 months and 30%, respectively. As gefitinib has demonstrated antitumour activity and an acceptable tolerability profile not typically associated with cytotoxic adverse events, such as hematological toxicities, combinations with cytotoxic drugs have been evaluated. Disappointingly, in chemotherapy-naive patients with advanced NSCLC, gefitinib 250 and 500 mg/day combined with platinum-based chemotherapy (gemcitabine/cisplatin or paclitaxel/carboplatin) did not produce prolonged survival, compared with chemotherapy alone in two large, randomised, placebo-controlled, multi-centre Phase III trials (INTACT [Iressa NSCLC Trial Assessing Combination Treatment]-1 and -2). Furthermore, in a recent randomised, placebo-controlled, Phase III trial (ISEL: IRESSA Survival Evaluation in Lung cancer), gefitinib failed to prolong survival compared with placebo in patients with advanced NSCLC who had failed one or more lines of chemotherapy. Subgroup analysis of ISEL suggested improved survival in patients of Asian origin and non-smokers. In addition, subset analyses of IDEAL and several retrospective studies have indicated that female gender, adenocarcinoma histology (especially bronchial alveolar carcinoma), non-smoker status and Asian ethnicity are factors which predict to response to gefitinib. Two types of somatic mutation clustered around the ATP binding pocket in the tyrosine kinase domain of the EGFR gene have been reported as possible surrogate biological markers for predicting response to gefitinib. Appropriate patient selection by clinical characteristics or genetical information is needed, both for future clinical trials of gefitinib and its routine use in the clinic among patients with advanced NSCLC.     

Pharmacogenetics of EGFR in lung cancer: perspectives and clinical applications

Lung cancer is a lethal disease, and most cases have already disseminated at the time of diagnosis. Driver mutations in the EGFR tyrosine kinase domain (mainly deletions in exon 19 and L858R mutation in exon 21) have been identified in lung adenocarcinomas, mostly in never smokers, at frequencies of 20-60%. The EGFR tyrosine kinase inhibitors (TKIs) gefitinib or erlotinib attain a response rate of 70% and progression-free survival of 9-13 months, although there are subgroups of patients with long-lasting remissions. No significant correlation between EGFR overexpression and response to treatment has been found, while controversial results have been reported regarding EGFR gene amplification. The pretreatment presence of the T790M mutation, initially identified as an acquired resistance mutation to treatment with EGFR TKIs, has also been reported and may indicate a genetically distinct disease. Finally, other genetic factors, such as mRNA expression of BRCA1 and components of the NF-κB pathway, can modulate response to EGFR TKIs in EGFR-mutated patients.     

Class act: safety comparison of approved tyrosine kinase inhibitors for non-small-cell lung carcinoma

Introduction: The past decade has seen the development and widespread use of tyrosine kinase inhibitors (TKIs) targeting a mutated EGFR (mEGFR) for the treatment of metastatic NSCLC. We discuss the main properties of the TKIs currently recommended for the treatment of mEGFR NSCLC: gefitinib, erlotinib and afatinib.

Areas covered: The mechanism of action, pharmacodynamics and pharmacokinetics of these drugs, with emphasis on the historical context of their preclinical and clinical development, will be covered, including potential resistance mechanisms to these first-generation TKIs that has driven the trial design for second and third generations of EGFR inhibitors. Six Phase III clinical trials comparing these three TKIs with cisplatin-based chemotherapy upfront for mEGFR NSCLC provide the basis for the comparative safety and toxicity analysis between these agents. Class-related toxicity of these EGFR inhibitors, including life-threatening effects, will be discussed.

Expert opinion: Toxicity and safety analysis from the Phase III trials of these agents in mEGFR populations suggests that afatinib has more frequent and severe side effects. Given that an efficacy advantage has not yet been demonstrated for afatinib over erlotinib and gefitinib, the consistent class toxicity profile of these agents means that gefitinib and erlotinib are a safer first-line treatment recommendation.     

Gefitinib in non-small cell lung cancer

Gefitinib (Iressa^TM), an orally-active tyrosine kinase inhibitor of the epidermal growth factor receptor (EGFR), is the first approved molecular-targeted drug for the management of patients with advanced non-small cell lung cancer (NSCLC). Two Phase II trials (IDEAL [Iressa Dose Evaluation in Advanced Lung Cancer]-1 and -2), evaluated the efficacy of gefitinib in advanced NSCLC patients who received ≤ 2 (IDEAL1) or ≥ 2 (IDEAL2) previous chemotherapy regimens. The response rate and disease control rate in IDEAL1 and -2 was 18/12% and 54/42%, respectively. The median survival time and one-year survival rate in both studies were ~ 7 months and 30%, respectively. As gefitinib has demonstrated antitumour activity and an acceptable tolerability profile not typically associated with cytotoxic adverse events, such as hematological toxicities, combinations with cytotoxic drugs have been evaluated. Disappointingly, in chemotherapy-naive patients with advanced NSCLC, gefitinib 250 and 500 mg/day combined with platinum-based chemotherapy (gemcitabine/cisplatin or paclitaxel/carboplatin) did not produce prolonged survival, compared with chemotherapy alone in two large, randomised, placebo-controlled, multi-centre Phase III trials (INTACT [Iressa NSCLC Trial Assessing Combination Treatment]-1 and -2). Furthermore, in a recent randomised, placebo-controlled, Phase III trial (ISEL: IRESSA Survival Evaluation in Lung cancer), gefitinib failed to prolong survival compared with placebo in patients with advanced NSCLC who had failed one or more lines of chemotherapy. Subgroup analysis of ISEL suggested improved survival in patients of Asian origin and non-smokers. In addition, subset analyses of IDEAL and several retrospective studies have indicated that female gender, adenocarcinoma histology (especially bronchial alveolar carcinoma), non-smoker status and Asian ethnicity are factors which predict to response to gefitinib. Two types of somatic mutation clustered around the ATP binding pocket in the tyrosine kinase domain of the EGFR gene have been reported as possible surrogate biological markers for predicting response to gefitinib. Appropriate patient selection by clinical characteristics or genetical information is needed, both for future clinical trials of gefitinib and its routine use in the clinic among patients with advanced NSCLC.