Vascular endothelial growth factor receptor as target for advanced non-small cell lung cancer therapy

Lung cancer remains the leading cause of malignancy-related mortality world-wide, in both men and women, with over a million cases diagnosed yearly. Non-small cell lung cancer (NSCLC) accounts for more than 80% of all lung cancers, and most patients are diagnosed with advanced disease. Although substantial progress has been made in the therapeutic options currently available for patients with advanced NSCLC, chemotherapy has apparently reached a plateau of effectiveness in improving survival in this subgroup of patients. Considerable efforts have been initiated to identify novel targets for new biological agents which may safely and effectively be administered to NSCLC patients. New blood vessel formation, known as angiogenesis, is a fundamental event in the process of tumor growth and metastatic dissemination. The vascular endothelial growth factor receptor (VEGFR) plays an essential role in tumor angiogenesis and proliferation, and has been a major focus of basic research and drug development in the field of Oncology. Approaches targeting VEGFR include mainly small molecule inhibitors of VEGFR tyrosine kinase activity. Among these, vandetanib, due to early findings of its antitumor activity and a good toxicity profile, has been largely investigated in advanced NSCLC. Other antiangiogenic drugs, such as sorafenib, and sunitinib are being tested in ongoing clinical trials which will further define their role in the management of NSCLC. Here we review the current results and give an overview of some of the future developments of the main anti-VEGFR drugs in the treatment of NSCLC patients.

Advances in chemotherapy in advanced non-small-cell lung cancer

IMPORTANCE OF THE FIELD

Lung cancer is the most common cancer in the world today, in terms of both incidence and mortality. Non-small-cell lung cancer (NSCLC) accounts for about 85% of all lung cancers diagnosis, and the majority of people diagnosed with NSCLC have advanced disease.

AREAS COVERED IN THIS REVIEW

In this review the main advances achieved in the medical treatment of advanced NSCLC are discussed, regarding both targeted therapies and chemotherapy. Among targeted therapies, recent data on the anti-vascular endothelial growth factor (VEGF) monoclonal antibody bevacizumab and the epidermal growth factor receptor tyrosyne kinase inhibitors (EGFR-TKIs) gefitinib and erlotinib are described. Among chemotherapeutic agents, the role of pemetrexed is discussed.

WHAT THE READER WILL GAIN

The reader will gain up-to-date information on the main advances, achieved in the last 3 years in the medical treatment of advanced NSCLC.

TAKE HOME MESSAGE

Some recent advances have changed the face of the first-line chemotherapy of advanced NSCLC, giving physicians more options to tailor choice in this challenging setting.

The potential role of insulin-like growth factor receptor inhibitors in the treatment of advanced non-small cell lung cancer

IMPORTANCE OF THE FIELD

Lung cancer is the leading cause of cancer-related mortality worldwide. NSCLC accounts for > 80% of all lung cancers. The treatment of advanced fit NSCLC patients seems to have reached a plateau. Considerable efforts have been initiated to identify new biological agents.

AREAS COVERED IN THIS REVIEW

Diagnosis of NSCLC histotype is becoming extremely important to address treatment. While non-squamous histology could start to benefit from the administration of several new drugs only recently, non-adenocarcinoma subtype seems to benefit from the administration of figitumumab (CP-751,871) a fully human anti-IGF 1 receptor (IGF-1R) mAb. In this paper, we reviewed the IGF-1R pathway and its inhibitors.

WHAT THE READER WILL GAIN

Approaches targeting IGF-1R include small-molecule IGF-1R tyrosine kinase inhibitors (TKIs), which are in preclinical and early clinical phases of development, and the mAbs, among which figitumumab is being investigated in Phase III trials of advanced NSCLC.

TAKE HOME MESSAGE

Figitumumab reported interesting results in the treatment of advanced non-adenocarcinoma NSCLC patients. Overall, in order to administer the optimal treatment to patients, a more definite histological diagnosis is mandatory.

Treating advanced non-small cell lung cancer in the elderly

More than 40% of cases of all lung cancers are diagnosed in patients over the age of 70 years. Elderly patients have more comorbidities and tend to be less tolerant to toxic medical treatments than their younger counterparts. Thus, clinical data obtained in a younger population cannot be automatically extrapolated to the great majority of nonselected elderly patients with non-small cell lung cancer (NSCLC). The bulk of prospective clinical data regarding chemotherapy and molecularly targeted therapy for elderly NSCLC patients come from studies in advanced disease. In elderly advanced NSCLC patients, single-agent chemotherapy with third-generation agents (vinorelbine, gemcitabine, taxanes) is to be considered the routine standard of care for unselected patients, based on phase II and III trials specifically designed for this special population. Cisplatin-based chemotherapy with cisplatin at attenuated doses has been demonstrated to be an active and feasible option in phase II trials. Among targeted therapies, the epidermal growth factor receptor tyrosine kinase inhibitors, erlotinib and gefitinib, have relevant phase II prospective data showing activity and good tolerability as first-line treatment in this population. Concerning the antivascular endothelial growth factor monoclonal antibody, bevacizumab, combined with chemotherapy, particular care must be taken for elderly patients because of the higher incidence of cardiovascular comorbidities. The lack of data on octogenarians suggest that clinicians should exercise caution when applying the existing data on chemotherapy and targeted therapies for patients aged 70-79 years to those aged >80 years. Further specifically designed clinical trials are needed to optimize medical treatment of NSCLC in elderly patients.

The emerging role of histology in the choice of first-line treatment of advanced non-small cell lung cancer: implication in the clinical decision-making

Lung cancer is the leading cause of cancer mortality worldwide. Non-small cell lung cancer (NSCLC), accounting for about 85% of all lung cancers, includes squamous carcinoma, adenocarcinoma and undifferentiated large cell carcinoma. The majority of patients have advanced disease at diagnosis, and medical treatment is the cornerstone of management. Several randomized trials comparing third-generation platinum-based doublets concluded that all such combinations are comparable in their clinical efficacy, failing to document a difference based on histology. However, recent evidences, arising from the availability of pemetrexed, have shown that histology represents an important variable in the decision making. The major progresses in the understanding cancer biology and mechanism of oncogenesis have allowed the development of several potential molecular targets for cancer treatment such as vascular growth factor and its receptors and epidermal growth factor receptor. Targeted drugs seem to be safer or more effective in a specific histology subtype. All of these data have led to choose the optimal first-line treatment of advanced NSCLC based on histologic diagnosis. However, this scenario raises a diagnostic issue: a specific diagnosis of NSCLC histologic subtype is mandatory. This review will discuss these new evidences in the first-line treatment of advanced NSCLC and their implication in the current clinical decision-making.

Erlotinib in the treatment of non-small cell lung cancer: current status and future developments

Erlotinib is an orally small molecule inhibiting the tyrosine kinase activity of the epidermal growth factor receptor (EGFR). Currently, erlotinib, at a standard oral daily dose of 150 mg, is licensed for the treatment of unselected recurrent non-small cell lung cancer (NSCLC) patients, however, it is being investigated in all stages of NSCLC. Erlotinib is well tolerated, with common toxicities including rash and diarrhoea. The optimization of the therapeutic impact of erlotinib in NSCLC will be more defined when reliable predictive factors are identified. An important step has been made in the molecular characterization of potentially sensitive NSCLC patients. In fact, we have learned that activation, somatic EGFR gene mutations within the tyrosine kinase domain, are associated with a high possibility of a long lasting therapeutic response to erlotinib. The present review discusses the role of erlotinib in the treatment of NSCLC.

Cetuximab and gemcitabine in elderly or adult PS2 patients with advanced non-small-cell lung cancer: The cetuximab in advanced lung cancer (CALC1-E and CALC1-PS2) randomized phase II trials

BACKGROUND

Two parallel randomized phase 2 trials were performed to choose the optimal way of combining cetuximab with gemcitabine in the first-line treatment of elderly (CALC1-E) and adult PS2 (CALC1-PS2) patients with advanced NSCLC.

METHODS

Stage IV or IIIB NSCLC patients, aged > or =70 years with PS 0-2 for CALC1-E or aged <70 with PS2 for CALC1-PS2, not selected for EGFR expression, were eligible. Patients were randomized to concomitant (gemcitabine, for a maximum of 6 cycles, plus cetuximab until progression) or sequential (gemcitabine, for a maximum of 6 cycles, followed by cetuximab) strategy. A selection design, with 1-year survival rate as the primary endpoint, was applied, requiring 58 elderly and 42 PS2 patients.

RESULTS

All planned patients were randomized. In sequential arms, 34.5% and 60.0% patients were not able to receive cetuximab after gemcitabine in CALC1-E and CALC1-PS2, respectively. Survival rates (95% CI) at 1-year for concomitant and sequential arms were 41.4% (23.5-61.1) and 31.0% (15.3-50.8) in CALC1-E and 27.3% (10.7-50.2) and 35.0% (15.4-59.2) in CALC1-PS2. In both studies, survival curves crossed at about 10 months and the worse arm until that time became the better one at 1-year. Toxicity was similar across treatment groups. In concomitant arm of CALC1-E (but not of CALC1-PS2), survival was longer for patients who developed skin toxicity within the first two cycles of treatment.

CONCLUSION

In both groups of patients, sequential strategy cannot be proposed for future trials because of low compliance. Inconsistency of survival outcomes makes also concomitant treatment not a candidate for further testing in unselected elderly and PS2 NSCLC patients.

Vaccines for the treatment of non-small cell lung cancer: a renewed anticancer strategy

Carcinoma of the lung is the leading cause of cancer death worldwide, with non-small cell lung cancer (NSCLC) constituting about 85% of all new diagnoses. Standard approaches for each NSCLC stage have reached a plateau in effectiveness. A variety of novel approaches are now being investigated to improve the outcome of this disease. Despite decades of research, no specific active cancer vaccine has, to date, been approved for NSCLC therapy; nevertheless, vaccine therapy has recently re-emerged as a potential therapeutic approach. In particular, several new paradigms have stemmed from recent clinical findings both in the use of combination therapy approaches with more sophisticated specific vaccines and in clinical trial design and endpoint analyses. Several vaccine therapies have been investigated in NSCLC, including in the early and advanced disease stages. The best results appear to be in the adjuvant settings and in locally advanced NSCLC. In fact, in these two settings, phase III randomized trials are ongoing evaluating the melanoma-associated antigen A3 vaccine and the liposomal BLP25 vaccine. This paper reviews the main clinical trials involving several different cancer vaccines employed in the treatment of early and advanced stage NSCLC, focusing on those in advanced stages of development.

Recent developments of targeted therapies in the treatment of non-small cell lung cancer

Non small cell lung cancer (NSCLC) is a lethal disease with poor prognosis. The main percentage of NSCLC patients are diagnosed to have an advanced disease. Standard treatment, such as chemotherapy and radiotherapy, has apparently reached a plateau of effectiveness in improving survival of advanced NSCLC patients. Hence, considerable efforts have started to be made in order to identify novel targets for new biological agents which may safely and effectively be administered to advanced NSCLC patients. Epidermal growth factor receptor (EGFR) and vascular endothelial growth factor (VEGF) and its receptors play an essential role in tumour proliferation. Approaches targeting EGFR and VEGF include monoclonal antibodies (mAbs) and small molecules inhibiting the corresponding receptor-tyrosine kinase activity. Erlotinib is a small molecule inhibitor of EGFR tyrosine-kinase which has brought significant improvements in median survival, quality of life and related symptoms, in an unselected population of advanced NSCLC patients in the second- or third-line setting. Bevacizumab, an anti-VEGF recombinant humanized mAb, is the first targeted agent which, when combined with chemotherapy, reported superior efficacy versus chemotherapy alone in the treatment of advanced NSCLC. ZD6474, a small molecule targeting VEGF tyrosine-kinase activity, showing early evidence of antitumour activity and the excellent toxicity profile, seems to be a promising agent for the treatment of advanced NSCLC. This review shows the latest and the future developments of erlotinib, bevacizumab and ZD6474 in the treatment of advanced NSCLC patients.

Cetuximab and other anti-epidermal growth factor receptor monoclonal antibodies in the treatment of non-small cell lung cancer

Non-small cell lung cancer (NSCLC) accounts for about 85% of all new diagnoses of lung cancer. Unfortunately, few NSCLC patients are suitable for radical treatment for curative intent. Because most patients with NSCLC have advanced disease at diagnosis, chemotherapy represents the standard of care, although, to date, a plateau has been reached with this approach. Improvements in the knowledge of tumor biology and mechanisms of oncogenesis have identified the epidermal growth factor receptor (EGFR), a member of the ErbB family, as a molecular target for NSCLC treatment. EGFR is commonly overexpressed in NSCLC and has been associated with impaired prognosis; therefore, its inhibition may lead, through the suppression of tumor proliferation, to improvement in clinical outcomes. Strategies to block EGFR include tyrosine kinase inhibitors, monoclonal antibodies, ligand-linked toxins, and antisense approaches. This article focuses on the treatment of NSCLC with the anti-EGFR monoclonal antibodies, including cetuximab, for which the largest amount of data in the literature exists. Recently, a phase III randomized trial performed in advanced NSCLC patients yielded a statistically significant survival advantage for patients treated with cetuximab plus chemotherapy versus chemotherapy alone. Other anti-EGFR monoclonal antibodies, such as panitumumab, matuzumab, nimotuzumab, and ch806, are in different stages of development for the treatment of advanced NSCLC.

Vascular disrupting agents: a novel mechanism of action in the battle against non-small cell lung cancer

Targeting vasculature, essential in oxygen and nutrient supply, represents a new frontier in the treatment of cancer. Apart from angiogenesis inhibitors that compromise the formation of new blood vessels, a second class of vascular disrupting agents (VDAs) targets endothelial cells and pericytes of the already established tumor vasculature, resulting in tumor ischemia and necrosis. VDAs have been divided into two types: ligand-directed VDAs and small molecules. Ligand-directed VDAs consist of targeting and effector moieties that are linked together. Their clinical efficacy appears limited because of cost and a lack of specificity and toxicity. Small molecules include two classes: the synthetic flavonoids, which work through induction of local cytokine production, and the tubulin-binding agents. The aim of this review is to discuss the hypothesized molecular mechanisms of action of VDAs and their early preclinical and clinical results, emphasizing ASA404, combretastatin A-4 disodium phosphate, ABT-751, and NPI-2358, reported in the treatment of non-small cell lung cancer, which is the leading cause of cancer death worldwide, and also to discuss future developments in this cancer population.

Tumor-related leucocytosis and chemotherapy-induced neutropenia: linked or independent prognostic factors for advanced non-small cell lung cancer?

Tumor-related leucocytosis is a paraneoplastic syndrome that is encountered occasionally in the clinical course of patients with non-small cell lung cancer (NSCLC). Autonomous production of hematopoietic cytokines (granulocyte-colony stimulating factor, granulocyte-macrophage-colony stimulating factor) has been identified in some of the patients presenting with this syndrome. In addition to the widely accepted prognostic factors of performance status and disease stage, recently, leucocytosis has been found to be a significant negative prognostic factor for overall survival and time to progression in patients with advanced-stage NSCLC in a pooled analysis of North Central Cancer Treatment Group trials, with data from about 1000 patients. A pooled analysis of an Italian Group with data from about 1300 patients has recently shown that neutropenia during chemotherapy is associated with increased survival of patients with advanced NSCLC. Similar results on the independent prognostic value of chemotherapy-induced neutropenia, have been reported by the Hellenic Oncology Research Group in a retrospective analysis on 850 patients. The absence of chemotherapy-induced neutropenia can be interpreted as a result of chemotherapy-underdosing. However, considering the negative prognostic value of leucocytosis, another interpretation should be ruled out: a proportion of the patients who do not experience chemotherapy-induced neutropenia may be associated with a worst prognosis because they may be characterized by base-line tumor-related leucocytosis and autonomous production of hematopoietic cytokines protecting them from chemotherapy-induced neutropenia. Prospective trials are needed to assess if NSCLC-related leucocytosis and chemotherapy-induced neutropenia are two linked or independent prognostic factors for NSCLC. This paper is a review of the available retrospective evidence on the aetiology and prognostic value of tumor-related leucocytosis and on the prognostic value of chemotherapy-induced neutropenia in advanced NSCLC. Moreover we try to hypothesize a possible correlation between these two phenomena and to give suggestions on the prospective evaluation of this hypothetical correlation in the next future.

Potential treatment options after first-line chemotherapy for advanced NSCLC: maintenance treatment or early second-line?

Although substantial progress has been made in the therapeutic options currently available for patients with advanced non-small cell lung cancer (NSCLC), the overall survival profile remains poor for most patients. One of the strategies currently under investigation with the aim of prolonging survival in NSCLC patients is maintenance treatment with either a chemotherapeutic agent or a molecularly targeted agent after first-line chemotherapy. Moreover, this can consist of drugs included in the induction regimen or other noncrossresistant agents. With the currently available data, maintenance treatment with a different noncrossresistant agent (i.e., an early second-line treatment) is perhaps the most promising strategy. The drug chosen for the early second-line treatment should be a well-tolerated agent, considering that patients have just completed a particularly toxic platinum-based chemotherapy. Extending treatment with targeted agents rather than chemotherapy can provide longer progression-free and overall survival times without increasing toxicity. However, at the moment, only progression-free survival has been shown to be consistently superior with maintenance approaches; the evaluation of survival benefits is warranted before defining this strategy as a possible treatment option. Further studies are warranted to establish the role of maintenance chemotherapy in patients with advanced NSCLC.

The role of cetuximab and other epidermal growth factor receptor monoclonal antibodies in the treatment of advanced non-small cell lung cancer

Lung cancer continues to be the leading cause of cancer-related deaths in the western civilization and developing countries. Non-small cell lung cancer (NSCLC) accounts for > 85% of all cases of lung cancer. Since most patients with NSCLC have advanced disease at diagnosis, to date chemotherapy with third-generation platinum-based doublets represents the standard of care. However, a plateau has been reached with the use of cytotoxic chemotherapy in advanced NSCLC. Advances in the knowledge of tumour biology and mechanisms of oncogenesis have granted the singling out of several molecular targets for NSCLC treatment. In particular, the epidermal growth factor receptor (EGFR), a member of the ErbB family and commonly overexpressed in NSCLC, is one of the most studied targets. Overexpression of EGFR has been associated with a poorer prognosis in patients with cancer, therefore its inhibition may lead to the suppression of tumor proliferation improving clinical outcome. Strategies to block EGFR include development of monoclonal antibodies to EGFR, tyrosine kinase inhibitors, ligand-linked toxins, and antisense approaches. This article will focus on cetuximab and other monoclonal antibodies and their applications in the treatment of advanced NSCLC.

The MILES-2G phase 2 study of single-agent gemcitabine with prolonged constant infusion in advanced non-small cell lung cancer elderly patients

BACKGROUND

Gemcitabine has been widely studied in elderly patients affected by advanced non-small cell lung cancer (NSCLC). A prolonged constant infusion (10 mg/m2/min) has been proposed as a way to improve its efficacy. Aim of this study is to describe activity and toxicity of single-agent gemcitabine given as prolonged infusion in the treatment of elderly patients with advanced NSCLC.

PATIENTS AND METHODS

Patients aged 70 years or older, with stage IV or IIIB (effusion/supraclavicular nodes) NSCLC, good performance status (0 or 1 according to ECOG classification) who had never received chemotherapy were eligible. Gemcitabine was administered at the dose of 1200 mg/m2 by prolonged infusion (10 mg/m2/min) on days 1 and 8 of each cycle. Courses were repeated every 21 days, for a maximum of 6 cycles, unless disease progression or severe toxicity. A single stage phase 2 design was applied, with 51 patients required to estimate a 25% +/- 10% response rate. Ten responses were required to define the treatment as active.

RESULTS

Fifty-one patients were enrolled, with a median age of 76 years (range 70-83). Two complete responses and seven partial responses were observed, for an overall response rate of 17.6% (95% exact C.I.: 8.4-30.9%). The median time to disease progression was 16.1 weeks (95% C.I.: 11.1-20.6) and the median overall survival was 41.3 weeks (95% C.I.: 27.6-50.6). There were 2 toxic deaths, due to bleeding and liver toxicity, and one patient had an ischemic stroke. Other non-haematological toxicities were: fatigue (44% of patients), grade 2-3 pulmonary toxicity (8%), grade 2-3 hepatic toxicity (16%). Nausea and stomatitis were mild and no cases of cardiac toxicity were observed. Haematological toxicity was mild, with no case of febrile neutropenia.

CONCLUSION

Gemcitabine at prolonged constant infusion produced a response rate lower than that required by study design and should no longer be of interest for the treatment of elderly patients with advanced NSCLC.

Combined chemo-radiotherapy for locally advanced non-small cell lung cancer: current status and future development

Currently, combinations of chemotherapy and radiotherapy are the standard treatment approach for locally advanced NSCLC patients. Concomitant chemo-radiotherapy, although associated with increased acute toxicity, has demonstrated to be the better strategy over sequential chemoradiotherapy, and it is to be considered a standard approach in patients with good performance status (0-1). However, the approach to locally advanced NSCLC and to chemo-radiotherapy regimens remains heterogeneous among oncologists, and clinical outcomes are yet disappointing. Thus, the search of new strategies is mandatory. The main fields of research aiming at improving the survival of locally advanced NSCLC patients are: the addition of further combination chemotherapy as induction or consolidation to concurrent chemo-radiotherapy, and the integration of molecularly targeted therapies into conventional chemo-radiotherapy regimens.

The potential role of pharmacogenomic and genomic in the adjuvant treatment of early stage non small cell lung cancer

Although notable progress has been made in the treatment of non-small-cell lung cancer (NSCLC) in recent years, this disease is still associated with a poor prognosis. Despite early-stage NSCLC is considered a potentially curable disease following complete resection, the majority of patients relapse and eventually die after surgery. Adjuvant chemotherapy prolongs survival, altough the absolute improvement in 5-year overall survival is only approximately 5%.Trying to understand the role of genes which could affect drug activity and response to treatment is a major challenge for establishing an individualised chemotherapy according to the specific genetic profile of each patient. Among genes involved in the DNA repair system, the excision repair cross-complementing 1 (ERCC1) is a useful markers of clinical resistance to platinum-based chemotherapy. In the International Lung Cancer Trial (IALT) adjuvant chemotherapy significantly prolonged survival among patients with ERCC1 negative tumors but not among ERCC1-positive patients. BRCA1 and ribonucleotide reductase M1 (RRM1), two other key enzymes in DNA synthesis and repair, appear to be modulators of drug sensitivity and may provide additional information for customizing adjuvant chemotherapy.Several clinical trials suggest that overexpression of class III beta-tubulin is an adverse prognostic factor in cancer since it could be responsible for resistance to anti-tubulin agents. A retrospective analysis of NCIC JBR.10 trial showed that high tubulin III expression is associated with a higher risk of relapse following surgery alone but also with a higher probability of benefit from adjuvant cisplatin plus vinorelbine chemotherapy.Finally, the use of gene expression patterns such as the lung metagene model could provide a potential mechanism to refine the estimation of a patient's risk of disease recurrence and could affect treatment decision in the management of early stage of NSCLC.In this review we will discuss the potential role of pharmacogenomic approaches to guide the medical treatment of early stage NSCLC.

The potential role of mTOR inhibitors in non-small cell lung cancer

The mammalian target of rapamycin (mTOR), a serine/threonine kinase, is a downstream mediator in the phosphatidylinositol 3-kinase/Akt signaling pathway, which plays a critical role in regulating basic cellular functions including cellular growth and proliferation. Currently, the mTOR inhibitor rapamycin and its analogues (CCI-779, RAD001, AP23573), which induce cell-cycle arrest in the G(1) phase, are being evaluated in cancer clinical trials. The mTOR inhibitors appear to be well tolerated, with skin reactions, stomatitis, myelosuppression, and metabolic abnormalities the most common toxicities seen. These adverse events are transient and reversible with interruption of dosing. Several pieces of evidence suggest a certain antitumor activity, including tumor regressions and prolonged stable disease, which has been reported among patients with a variety of malignancies, including non-small cell lung cancer (NSCLC). These promising preliminary clinical data have stimulated further research in this setting. Here, we review the basic structure of the pathway together with current results and future developments of mTOR inhibitors in the treatment of NSCLC patients.