Vandetanib for the treatment of non-small-cell lung cancer

Introduction: The use of targeted therapies in the treatment of advanced non-small-cell lung cancer (NSCLC) is increasing, especially as conventional chemotherapy affords relatively small benefits at a cost of increased toxicity. Two of the more established therapeutic targets in NSCLC are the vascular endothelial growth factor receptor (VEGFR) and epidermal growth factor receptor (EGFR). Vandetanib is an orally available inhibitor of VEGFR and EGFR signalling and is an attractive therapeutic agent owing to the simultaneous inhibition of both pathways.

Areas covered: This review encompasses the clinical efficacy, safety and tolerability of vandetanib in advanced NSCLC. Of particular interest are the randomized Phase III clinical trials, which did not show clinically significant overall survival benefit for vandetanib monotherapy or in combination with standard chemotherapy regimens.

Expert opinion: Vandetanib has anti-tumour activity in NSCLC, with improved objective responses and disease control. However, significant survival benefits were not demonstrated in Phase III clinical trials and at present vandetanib is not in further development for use in NSCLC.     

Vandetanib: An overview of its clinical development in NSCLC and other tumors

Vandetanib is an oral inhibitor of vascular endothelial growth factor receptor 2 (VEGFR-2), epidermal growth factor receptor (EGFR) and Ret tyrosine kinases involved in tumor growth, progression and angiogenesis. Phase I studies indicated that the recommended dose of vandetanib as a single agent is 300 mg/day. Rash, diarrhea, hypertension and asymptomatic Q-Tc prolongation were the most common adverse events. Four randomized phase III clinical trials evaluated the efficacy of vandetanib in non-small cell lung cancer (NSCLC) in combination with docetaxel (ZODIAC), pemetrexed (ZEAL) or as a single agent (ZEST and ZEPHYR). Only the ZODIAC trial met its primary endpoint (progression-free survival [PFS]), while no study showed an advantage in overall survival with vandetanib. No significant antitumor activity has been observed in small cell lung cancer, advanced ovarian, colorectal, breast, prostate cancer and multiple myeloma. In advanced metastatic medullary thyroid cancer, one randomized phase III clinical trial has demonstrated that vandetanib can significantly improve response rate, PFS and time to worsening of pain. Several key questions remain to be addressed regarding the identification of clinical or molecular biomarkers predictive of response, the choice of the optimal dose or schedule of vandetanib and the safety of long-term administration. The results of ongoing trials in untreated patients with advanced NSCLC and other tumors should better define the optimal clinical application of vandetanib.     

Vandetanib (ZD6474): an orally available receptor tyrosine kinase inhibitor that selectively targets pathways critical for tumor growth and angiogenesis

Vandetanib (ZD6474; ZACTIMA, AstraZeneca) is a once-daily, orally available agent with potential for use in a number of solid tumor types. Vandetanib targets key signaling pathways in cancer by inhibiting VEGFR-dependent tumor angiogenesis, and EGFR- and RET-dependent tumor cell proliferation and survival. Phase I studies showed vandetanib to be generally well tolerated at doses of < or = 300 mg/day, with a pharmacokinetic profile that supports once-daily oral administration. Phase II evaluation of vandetanib in patients with advanced refractory NSCLC has demonstrated improvements in progression-free survival both as monotherapy (versus gefitinib) and in combination with docetaxel (versus docetaxel alone). These positive outcomes have led to the initiation of Phase III trials of vandetanib in advanced NSCLC. Clinical development is also ongoing in other tumor types and encouraging evidence of antitumor activity has been reported in patients with metastatic hereditary medullary thyroid cancer.     

Vandetanib, a novel multitargeted kinase inhibitor, in cancer therapy

In clinical trials thus far, single-targeted kinase inhibitors have shown only limited success in demonstrating survival benefits in cancer. This has led to the development of multitargeted kinase inhibitors capable of disrupting various mitogenic pathways in both cancer cells and associated vasculature. Vandetanib is a novel multitargeted kinase inhibitor exhibiting potent activity against vascular endothelial growth factor receptor-2 (VEGFR-2; kinase insert domain-containing receptor [KDR]) and, to a lesser extent, epidermal growth factor receptor (EGFR) and RET kinase. Vascular endothelial growth factor (VEGF) and VEGFR-2 play a pivotal role in regulating angiogenesis and vascular permeability in cancers. In addition to its antiangiogenic effects, vandetanib acts against EGFR, which is overexpressed or mutated in several solid tumors. Furthermore, vandetanib exerts activity against oncogenic RET kinase, the overexpression of which is common in medullary and papillary thyroid carcinomas. Therefore, the multitargeted kinase inhibitor vandetanib represents a new approach, targeting both tumor cells and tumor-associated endothelial cells. Preclinical studies of vandetanib have demonstrated antitumor efficacy against multiple human cancer xenografts in subcutaneous, orthotopic and metastatic models. Phase I clinical trials have demonstrated that vandetanib is well tolerated. Common adverse events included rash, diarrhea and asymptomatic QTc prolongation. Phase II clinical studies in patients with non-small-cell lung cancer have shown promising results, employing vandetanib as both monotherapy and in combination with docetaxel. Phase II studies in other cancers have likewise been initiated. This review summarizes preclinical and clinical studies of vandetanib for the treatment of cancers.     

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.     

Vandetanib: in medullary thyroid cancer

Vandetanib, an orally active, small-molecule, multitargeted tyrosine kinase inhibitor, demonstrates potent inhibitory activity against vascular endothelial growth factor receptor (VEGFR)-2 and -3, epidermal growth factor receptor (EGFR) and the rearranged during transfection (RET) tyrosine kinase receptor. The large (n=331), randomized, double-blind, multinational ZETA trial compared vandetanib at a dosage of 300 mg once daily with placebo in patients with unresectable, locally advanced or metastatic, hereditary or sporadic, medullary thyroid cancer. During a median follow-up period of 2 years, vandetanib demonstrated statistically significant clinical benefits over placebo with respect to the primary endpoint, namely progression-free survival (PFS), and a range of secondary endpoints, which included objective response rate, disease control rate, time to worsening of pain and calcitonin biochemical response rate. The PFS benefit with vandetanib was mostly consistent across patient subgroups based on baseline characteristics and disease status. Although the correlation between RET mutation status and clinical outcome could not be clearly evaluated in this trial, it is notable that, among patients with sporadic disease, vandetanib not only demonstrated a PFS benefit in the subgroup confirmed as having a RET mutation, but also in the subgroup for whom the RET mutation status was unknown. Vandetanib was generally well tolerated in the ZETA trial; the majority of adverse events were manageable according to standard clinical practice alone or in combination with vandetanib dose reductions. The adverse event of most concern is corrected QT interval prolongation, particularly in view of the long terminal elimination half-life of the drug.     

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.     

Vandetanib for the treatment of lung cancer

INTRODUCTION: VEGF and EGFR are validated pathways for targeted therapy in non-small cell lung cancer (NSCLC). Once considered to be separate targets, VEGF and EGFR are now shown to have interconnected downstream pathways, potentiating the effectiveness of their dual signaling inhibition in cancer therapy. Molecules such as vandetanib that inhibit VEGFR and EGFR have also been reported to inhibit other receptors, including RET and additional kinases, and may be beneficial in treating patients with solid tumors. AREAS COVERED: This review covers the significance of targeting VEGF and EGFR in the treatment of NSCLC and the rationale behind their dual inhibition. Clinical trials that evaluate the use of vandetanib in the setting of refractory NSCLC are also explored. EXPERT OPINION: Vandetanib is currently not approved in the setting of NSCLC. However, its approval for medullary thyroid cancer makes it promising for identifying markers and potentially a NSCLC patient population who will benefit from the treatment.     

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.     

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.     

Novel investigational drugs for gastric cancer

Background: Gastric cancer still represents a leading cause of death worldwide. Several cytotoxic agents have demonstrated activity and combination regimens improve progression-free survival, overall survival and quality of life. Nevertheless, now there is no standard therapy for advanced gastric cancer patients. Objective: To evaluate the role of new investigational agents. Methods: We analysed Phase I, II and III studies that evaluated tailored drugs directed against the epidermal growth factor receptor (EGFR), the c-erbB2, the vascular endothelial growth factor (VEGF), the vascular endothelial growth factor receptor (VEGFR), the matrix metalloproteinases (MMP) and the mammalian target of rapamycin (mTOR). Conclusion: Data from Phase II trials indicate the potential of improved efficacy of chemotherapy when administered in combination with bevacizumab and cetuximab. Trastuzumab results are ongoing, while marimastat has not obtained clinical developments even if it has demonstrated to be an active drug in this setting of patients.     

Novel combination chemotherapy in the treatment of non-small cell lung cancer

Treatment of patients with advanced non-small cell lung cancer (NSCLC) remains a vexing problem and long-term survival beyond 5 years is extremely rare. Five new agents, paclitaxel, docetaxel, vinorelbine, gemcitabine and irinotecan, have been introduced for the treatment of NSCLC and investigated extensively both preclinically and clinically. Monotherapy with one of these agents has produced survival benefits over the best supportive care in Phase III studies. Combination chemotherapy with a new agent and platinum produced a higher response rate than conventional cisplatin-based chemotherapy and improved survival was observed in some randomised trials. There was little difference in efficacy and toxicity between the chemotherapeutic regimens with a new agent and a platinum in Phase III trials, suggesting the clinical utility of these regimens is similar. Many trials have focused on regimens containing two new agents, with or without platinum. Preliminary results of Phase III trials of three drug combinations versus two drug combinations suggested the former to be more promising, in terms of response rates and survival. Whether the era of platinum-based chemotherapy in the treatment of NSCLC should continue or not must be determined by Phase III trials, evaluating the use of a platinum agent with one of the new agent combinations. These aggressive chemotherapeutic combinations will hopefully improve survival and quality of life for patients with advanced NSCLC.     

Novel combination chemotherapy in the treatment of non-small cell lung cancer

Treatment of patients with advanced non-small cell lung cancer (NSCLC) remains a vexing problem and long-term survival beyond 5 years is extremely rare. Five new agents, paclitaxel, docetaxel, vinorelbine, gemcitabine and irinotecan, have been introduced for the treatment of NSCLC and investigated extensively both preclinically and clinically. Monotherapy with one of these agents has produced survival benefits over the best supportive care in Phase III studies. Combination chemotherapy with a new agent and platinum produced a higher response rate than conventional cisplatin-based chemotherapy and improved survival was observed in some randomised trials. There was little difference in efficacy and toxicity between the chemotherapeutic regimens with a new agent and a platinum in Phase III trials, suggesting the clinical utility of these regimens is similar. Many trials have focused on regimens containing two new agents, with or without platinum. Preliminary results of Phase III trials of three drug combinations versus two drug combinations suggested the former to be more promising, in terms of response rates and survival. Whether the era of platinum-based chemotherapy in the treatment of NSCLC should continue or not must be determined by Phase III trials, evaluating the use of a platinum agent with one of the new agent combinations. These aggressive chemotherapeutic combinations will hopefully improve survival and quality of life for patients with advanced NSCLC.     

Molecularly-targeted therapies for non-small cell lung cancer

Targeting cell-signalling pathways that confer survival advantage to cancer cells has become a major focus of investigation for the treatment of various malignancies. Non-small cell lung cancer (NSCLC), a disease with wide molecular heterogeneity, has become a main testing ground for the evaluation of various targeted agents. Inhibition of the epidermal growth factor pathway with erlotinib results in improved survival and symptom control for patients with advanced NSCLC who progressed following one or two prior chemotherapy regimens. Gefitinib, the first epidermal growth factor receptor (EGFR) inhibitor to be approved by the FDA, failed to demonstrate survival advantage over placebo in a large Phase III trial for patients with advanced NSCLC. The results of this study have raised several important clinical and biological issues that may be relevant for the development of other targeted agents. Recent identification of mutations in the ATP-binding pocket of the EGFR is the first step towards proper patient selection for therapy with an EGFR tyrosine kinase inhibitor. In addition, predictive potential has also been seen with EGFR gene amplification. It is unclear whether monoclonal antibodies against the EGFR may be active independent of the EGFR mutation, as the site of action is different from tyrosine kinase inhibitors. A recent randomised clinical trial that combined the antiangiogenic agent bevacizumab with chemotherapy has demonstrated survival advantage over chemotherapy alone for certain subsets of patients with advanced NSCLC. The exciting results of this study represent an important advance in the treatment of patients with advanced NSCLC.     

Molecularly-targeted therapies for non-small cell lung cancer

Targeting cell-signalling pathways that confer survival advantage to cancer cells has become a major focus of investigation for the treatment of various malignancies. Non-small cell lung cancer (NSCLC), a disease with wide molecular heterogeneity, has become a main testing ground for the evaluation of various targeted agents. Inhibition of the epidermal growth factor pathway with erlotinib results in improved survival and symptom control for patients with advanced NSCLC who progressed following one or two prior chemotherapy regimens. Gefitinib, the first epidermal growth factor receptor (EGFR) inhibitor to be approved by the FDA, failed to demonstrate survival advantage over placebo in a large Phase III trial for patients with advanced NSCLC. The results of this study have raised several important clinical and biological issues that may be relevant for the development of other targeted agents. Recent identification of mutations in the ATP-binding pocket of the EGFR is the first step towards proper patient selection for therapy with an EGFR tyrosine kinase inhibitor. In addition, predictive potential has also been seen with EGFR gene amplification. It is unclear whether monoclonal antibodies against the EGFR may be active independent of the EGFR mutation, as the site of action is different from tyrosine kinase inhibitors. A recent randomised clinical trial that combined the antiangiogenic agent bevacizumab with chemotherapy has demonstrated survival advantage over chemotherapy alone for certain subsets of patients with advanced NSCLC. The exciting results of this study represent an important advance in the treatment of patients with advanced NSCLC.     

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 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.     

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.     

Vandetanib mediates anti-leukemia activity by multiple mechanisms and interacts synergistically with DNA damaging agents

Vandetanib is an orally active small molecule tyrosine kinase inhibitor (TKI) with activity against several pathways implicated in malignancy including the vascular endothelial growth factor receptor pathway, the epidermal growth factor receptor pathway, the platelet derived growth factor receptor β pathway, and REarranged during Transfection pathway. To determine if vandetanib-mediated inhibition of receptor tyrosine kinases is a potential therapeutic strategy for pediatric acute leukemia, these studies aimed to characterize the activity of vandetanib against acute leukemia in vitro. Treatment of leukemia cell lines with vandetanib resulted in a dose-dependent decrease in proliferation and survival. Vandetanib’s anti-leukemic activity appeared mediated by multiple mechanisms including accumulation in G1 phase at lower concentrations and apoptosis at higher concentrations. Alterations in cell surface markers also occurred with vandetanib treatment, suggesting induction of differentiation. In combination with DNA damaging agents (etoposide and doxorubicin) vandetanib demonstrated synergistic induction of cell death. However in combination with the anti-metabolite methotrexate, vandetanib had an antagonistic effect on cell death. Although several targets of vandetanib are expressed on acute leukemia cell lines, expression of vandetanib targets did not predict vandetanib sensitivity and alone are therefore not likely candidate biomarkers in patients with acute leukemia. Interactions between vandetanib and standard chemotherapy agents in vitro may help guide choice of combination regimens for further evaluation in the clinical setting for patients with relapsed/refractory acute leukemia. Taken together, these preclinical data support clinical evaluation of vandetanib, in combination with cytotoxic chemotherapy, for pediatric leukemia.     

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.