Update on new drugs in small cell lung cancer

INTRODUCTION

Small cell lung cancer (SCLC) will account for 25,000 to 32,000 new lung cancer cases in the USA in 2010. Current treatmenta pproaches include platinum-based chemotherapy and etoposide with or without radiation therapy depending on stage and performance status. Five-year survival is approximately 25% for patients with limited stage disease and 1 -- 2% for patients with extensive stage disease and has noti mproved in almost two decades.

AREAS COVERED

This article reviews the results of recent clinical trials that have evaluated targeted agents and novel cytotoxic agents alone or in combination with standard chemotherapy in the treatment of patients with SCLC.

EXPERT OPINION

The lack of a targeted approach to the treatment of patients with SCLC has led investigators to evaluate a multitude of agents with overwhelmingly negative results. A more systematic approach to clinical trials in patients is needed to improve outcomes for patients with this disease.

[Molecular targeted therapies in small-cell lung cancer]

Small-cell lung cancers (SCLC) are aggressive malignancies, however, characterized by high primary chemosensitivity. Unfortunately, for the vast majority of patients, relapse is the rule with emergence of secondary resistance mechanisms. In the era of molecular targeted therapies, characterization of a number of molecular abnormalities has encouraged implementation of several clinical trials. This literature review summarizes the various pharmacological approaches used in SCLC to improve survival in localized and extensive forms of the disease. Initial trials with molecular targeted therapies have not been able to improve clinical outcome compared to the standard etoposide-cisplatin chemotherapy regimen in extensive forms. However, new targets continue to be identified and many treatments are currently being assessed, including blockade of angiogenesis, signal transduction, cell cycle or induction of apoptosis.

Phase II study of cisplatin plus etoposide and bevacizumab for previously untreated, extensive-stage small-cell lung cancer: Eastern Cooperative Oncology Group Study E3501

PURPOSE

To investigate the efficacy and safety of bevacizumab plus cisplatin and etoposide in patients with extensive-stage disease, small-cell lung cancer (ED-SCLC).

PATIENTS AND METHODS

In this phase II trial, 63 patients were treated with bevacizumab 15 mg/kg plus cisplatin 60 mg/m(2) and etoposide 120 mg/m(2), which was followed by bevacizumab alone until death or disease progression occurred. The primary end point was the proportion of patients alive at 6 months without disease progression (ie, progression-free survival [PFS]). Secondary end points included overall survival (OS), objective response rate, and toxicity. Correlative studies were performed to explore the relationship between baseline and changes in plasma vascular endothelial growth factor (VEGF), soluble cell adhesion molecules (ie, vascular cell adhesion molecule [VCAM], intercellular cell adhesion molecule [ICAM], and E-selectin) and basic fibroblast growth factor and outcome.

RESULTS

The 6-month PFS was 30.2%, the median PFS was 4.7 months, and OS was 10.9 months. The response rate was 63.5%. The most common adverse event was neutropenia (57.8%). Only one patient had grade 3 pulmonary hemorrhage. Patients who had high baseline VCAM had a higher risk of progression or death compared with those who had low baseline VCAM levels. No relationships between outcome and any other biomarkers were seen.

CONCLUSION

The addition of bevacizumab to cisplatin and etoposide in patients with ED-SCLC results in improved PFS and OS relative to historical controls who received this chemotherapy regimen without bevacizumab. This regimen appears to be well tolerated and has minimal increase in toxicities compared with chemotherapy alone. Baseline VCAM levels predicted survival, but no other relationships among treatment, biomarkers, and outcome were identified.

[Small cell lung cancer]

With about 20% of all lung cancers small cell lung cancer (SCLC) represents a major subset of this entity. Although therapeutic improvements did not receive as much attention as in non small cell lung cancer (NSCLC), many small steps of clinical progress have been achieved within the last 20 years. An optimal treatment should be based on an interdisciplinary treatment plan. The standard treatment in localized stages represents combined radiation and chemotherapy. Cisplatin and etoposide are in this concern considered as a gold standard. 3D-planned conformal radiotherapy should start as early as possible and should be applied concomitantly to chemotherapy and in certain cases even in a hyperfractionated treatment protocol. In very early stages surgical resection could be an option in selected cases. In advanced stages a platinum-based doublet offers high response rates. As already established in limited disease prophylactic cranial irradiation is now also indicated in extensive disease in case of any tumor remission. In the second line treatment and in patients with reduced performance status topotecan is recommended. Similar as in NSCLC pemetrexed might become an alternative treatment option in the second line setting. In the field of new targeted therapies bevacizumab achieved the most promising results. The present review highlights historical milestones and up-to-date trends in radiotherapy, chemotherapy and surgery. Furthermore, the role of experimental strategies and the management of certain special clinical situations are discussed.

[Updated strategies in Small Cell Lung Cancer post ASCO 2007]

Small Cell Lung Cancer (SCLC) is associated with intensive nicotine consumption and characterized by a very aggressive growth rate. Furthermore, metastases often appear very early. At the annual meeting of the "American Society of Clinical Oncology" (ASCO) 2007, recent issues which will influence the daily clinical practice were presented. New chemotherapy combinations such as carboplatin/irinotecan or pemetrexed as well as targeted therapies e.g. bevacizumab in combination with chemotherapy could extend our therapeutic options. A genetic polymorphism, which influences the pharmacokinetic of irinotecan, turned out to be one reason for the different outcome of an irinotecan/cisplatin therapy in a Japanese and Northern American population. In the field of radiotherapy, a phase III study showed for the first time a significant benefit in overall survival by prophylactic cranial radiation in the setting of extensive disease.