Raltitrexed–Oxaliplatin combination chemotherapy is inactive as second-line treatment for malignant pleural mesothelioma patients

Emerging therapies in malignant pleural mesothelioma

Malignant pleural mesothelioma (MPM) is a rare cancer of the pleural surfaces frequently related to asbestos exposure. It is characterized by a poor prognosis even for patients treated with trimodality therapy, including surgery, chemotherapy and radiotherapy. Moreover, the majority of patients are not candidates for surgery due to disease advanced stage or medical comorbidities. For these patients, the survival rate is even lower and few therapeutic options are currently available. Nevertheless, many interesting novel approaches are under investigation, among which immunotherapy represents one of the most promising emerging strategies. In this review, we will discuss the role of new therapeutic options, particularly immunotherapy, and present the results of the most important and promising clinical trials.

A systematic review and meta-analysis of second-line therapies for treatment of mesothelioma

INTRODUCTION

Advanced malignant pleural mesothelioma (MPM) is generally treated with platinum/pemetrexed-based first-line therapy. Once the disease progresses, evidence for the efficacy of palliative treatments is lacking, and platinum re-challenge or single-agent chemotherapy are commonly used. To assess the effects of cytostatic or targeted therapy for treating MPM, we performed a systematic review and meta-analysis.

MATERIAL AND METHODS

PubMed, the Cochrane Library, and Embase databases were searched to identify published articles on second-line treatments for recurrent or advanced mesothelioma. Inclusion criteria were publication in the English language, describing clinical trials with 20 or more patients, and evaluability for efficacy and for receiving second-line systemic therapies. Data were pooled using number of events/number of evaluable patients, median overall survival (OS) and progression-free survival (PFS), according to a fixed or random effect model. Pooled median OS was the primary endpoint.

RESULTS

A total of 49 eligible studies (n = 3938 patients; range, 12-400) were identified. Median progression-free survival (PFS) was 3.4 months (95%CI 2.87-3.93). Median pooled OS was 7.86 (95%CI 7.01-8.72). The pooled overall response rate (ORR) was 8.63% (95%CI 6-11.26), and the pooled disease control rate (DCR) was 54.8% (95%CI 48.9-60.6). Median pooled OS with platinum- and pemetrexed-based chemotherapy were 7.93 and 7.78 months, respectively.

CONCLUSIONS

There remains uncertainty about the ideal second-line agent for MPM. Based on this meta-analysis, palliative chemotherapy or other experimental agents can be considered for patients with MPM who desire further treatment after their disease has progressed, during or after first-line therapy.

Medical treatment of malignant pleural mesothelioma relapses

There are not established treatments for patients with advanced malignant pleural mesothelioma that progressed after first-line chemotherapy with cisplatin and pemetrexed. Retrospective analyses suggest a possible role for rechallenge with pemetrexed for selected patients. Phase II trials demonstrate a modest efficacy of vinorelbine monotherapy with a response rate ranging between 0% and 18% and a tolerable toxicity profile. Combination schedules, despite an increased toxicity, fail to demonstrate an improved efficacy. To date, genome wide analyses did not show molecular targets suitable for therapy and biological drugs did not exert a significant efficacy in clinical trials. Immunotherapy has given a hint of efficacy in early clinical trials but definitive evaluations are still ongoing.

Chemotherapy treatment in malignant pleural mesothelioma: a difficult history

Malignant pleural mesothelioma (MPM) is a rare neoplasm that typically arises from mesothelial surfaces of the pleural cavity. Despite treatment improvements, it carries a dismal prognosis. The majority of patients either have unresectable disease or are not candidates for surgery due to medical comorbidities or old age. For such patients, chemotherapy (CT) represents the gold-standard treatment. To date, combination CT with cisplatin plus pemetrexed represents the most widely used regimen in first-line setting for patients with unresectable MPM. Other first-line options are currently available, including the use of raltitrexed instead of pemetrexed combined with platinum. In this review, we discuss the role of CT in MPM mainly focusing on the results of the trials conducted in first-line setting.

Systematic review of response rates of sarcomatoid malignant pleural mesotheliomas in clinical trials

RATIONALE

Malignant pleural mesothelioma is an almost universally fatal malignancy primarily related to asbestos exposure. Based on the differences in immunologic markers and gene expression between histologic subtypes of mesothelioma, and our clinical impression that response rates vary by histology, we decided to examine the reported response rates of mesothelioma subtypes.

OBJECTIVES

Our objective was to compare the response rates of sarcomatoid mesotheliomas to the overall response rates in published clinical trials.

METHODS

We searched PubMed for "mesothelioma" with the clinical trials filter selected. We included articles published between January 1, 2000 and March 20, 2014 in which subjects received first or second line systemic therapy for malignant pleural mesothelioma. Studies investigating multi-modality therapy including surgery were excluded. Response rates [including 95% confidence intervals (95% CI)] were estimated for the entire patient cohort and then separately for subjects with sarcomatoid tumors.

MEASUREMENTS AND MAIN RESULTS

We reviewed 544 publications of which 41 trials met our inclusion criteria. Eleven of these trials did not include patients with sarcomatoid mesothelioma (27% of eligible studies). The remaining 30 publications included 1475 subjects, 1011 with epithelioid tumors (68.5%), 203 with biphasic tumors (13.8%), 137 with sarcomatoid tumors (9.3%) and 124 with unknown subtypes (8.4%). In total, there were 323 responses (21.9%, complete and partial responses, 95% CI: 16.3, 28.8) to systemic therapy across all histological subtypes. In patients with sarcomatoid tumors (n=137) 19 responses were observed. This accounted for 5.9% of all responses and yields a 13.9% (95% CI: 8.6, 21.6) response rate for patients with sarcomatoid tumors. Multiple biases likely affected this systematic review.

CONCLUSION

Response rates for different histological subtypes of malignant pleural mesothelioma are infrequently reported. Partial and complete responses to systemic therapies appear to be less common among patients with sarcomatoid tumors.

Vinorelbine in pemetrexed-pretreated patients with malignant pleural mesothelioma

BACKGROUND

Pemetrexed-platinum chemotherapy is the standard first-line treatment of unresectable malignant pleural mesothelioma (MPM). At progression, patients are generally selected to experimental trials, when available, or, in every-day clinical practice, they are offered second-line chemotherapy. The optimal treatment has not yet been defined. The aim of this retrospective, single-center study was to evaluate the activity and toxicity of vinorelbine administered to a consecutive series of pemetrexed-pretreated MPM patients.

METHODS

Vinorelbine 25 mg/m(2) was administered intravenously as a single agent on days 1, 8 every three weeks, either as second-line (2L) or further-line (>2L) therapy. Treatment was repeated for a maximum of 6 cycles, until progression, or unacceptable toxicity.

RESULTS

Fifty-nine patients were included in this analysis. Vinorelbine was given to 34 patients as 2L, and to 25 as > 2L treatment. The median age was 69 years (range 45-80). Forty-two patients (71.2%) had a good EORTC prognostic score. Partial response was observed in 9 (15.2%) cases, stable disease in 20 (33.9%). The overall disease control rate (DCR) was 49.1%. Median progression-free survival (PFS) and overall survival (OS) were 2.3 and 6.2 months, respectively. ECOG performance status (PS) (HR(0 vs. 1-2) 0.50; 95%CI: 0.3-0.8; p = 0.014) and PFS ≥ 6 months following first-line (FL) chemotherapy (HR(FL-PFS>6 ms vs. <6 ms) 0.50; 95%CI: 0.3-0.9; p = 0.031) were significantly associated to OS in multivariate analysis. No difference was observed in terms of DCR, PFS, and OS in relation to age, histology, sex, line of vinorelbine therapy, or response to FL treatment. Hematological toxicity was acceptable, with grade 3/4 neutropenia occurring in 5 (8.4%) patients, and there were no cases of febrile neutropenia. The main non-hematological toxicities were grade 2 fatigue in 17 (28.8%) and constipation in 7 (11.8%) patients.

CONCLUSIONS

Vinorelbine was moderately active in pemetrexed-pretreated MPM patients, with an acceptable toxicity profile, particularly in patients with ECOG-PS0 and FL-PFS ≥ 6 months.

Second-line chemotherapy in malignant pleural mesothelioma: results of a retrospective multicenter survey

The pemetrexed-cisplatin chemotherapy is standard of care in first-line (FL) treatment of malignant pleural mesothelioma (MPM). The second-line (SL) chemotherapy is considered, but the optimal treatment has not been defined yet. The aim of this study was to evaluate the clinical outcomes of SL-therapy in a series of MPM-patients included in a retrospective multicenter database. Clinical records of MPM-patients who received SL-treatment from 1996 to 2008 were reviewed. Study endpoints were response, overall-survival (OS), and progression-free-survival (PFS) for SL, stratified for patient characteristics, FL-outcomes, and type of SL. Out of 423 patients, 181 with full clinical data were identified. Patients' characteristics: median-age 64 years (range: 36-85); male gender 115 (63.5%); good EORTC-score 109 (60.2%); epithelial histology 135 (74.6%). After FL, 147 (81.2%) patients achieved disease-control (DC) and 45 had a time-to-progression≥12 months (TTP≥12). After SL, 95 patients (52.6%) achieved DC (21 response; 74 stable-disease); median PFS and OS were 4.3 and 8.7 months, respectively. According to multivariate analysis, DC after SL-therapy was significantly related to pemetrexed-based treatment (OR: 2.46; p=0.017) and FL-TTP≥12 (OR: 3.50; p=0.006). PFS was related to younger age (<65 years) (HR: 0.70; p=0.045), ECOG-PS0 (HR: 0.67; p=0.022), and FL-TTP≥12 (HR: 0.45; p<0.001). OS was significantly related to ECOG-PS0 (HR: 0.43; p<0.001) and to FL-TTP≥12 (HR: 0.54; p=0.005). In pemetrexed pre-treated patients, re-treatment with a pemetrexed/platinum combination significantly reduced the risk-of-death than pemetrexed alone (HR: 0.11; p<0.001). In conclusion, SL-chemotherapy seems to be active in MPM-patients, particularly in younger patients with ECOG-PS0 and prolonged TTP after FL-pemetrexed-based chemotherapy. In selected patients, re-challenge with pemetrexed-based regimens, preferentially associated with platinum-compound, appears to be an option for SL-setting. Considering the important limitations of this study, due to retrospective nature and the possible selection bias, prospective clinical trials are warranted to clarify these issues.

Investigational approaches for mesothelioma

Malignant pleural mesothelioma (MPM) is a rare, aggressive tumor with a poor prognosis. In view of the poor survival benefit from first-line chemotherapy and the lack of subsequent effective treatment options, there is a strong need for the development of more effective treatment approaches for patients with MPM. This review will provide a comprehensive state of the art of new investigational approaches for mesothelioma. In an introductory section, the etiology, epidemiology, natural history, and standard of care treatment for MPM will be discussed. This review provide an update of the major clinical trials that impact mesothelioma treatment, discuss the impact of novel therapeutics, and provide perspective on where the clinical research in mesothelioma is moving. The evidence was collected by a systematic analysis of the literature (2000-2011) using the databases Medline (National Library of Medicine, USA), Embase (Elsevier, Netherlands), Cochrane Library (Great Britain), National Guideline Clearinghouse (USA), HTA Database (International Network of Agencies for Health Technology Assessment - INAHTA), NIH database (USA), International Pleural Mesothelioma Program - WHOLIS (WHO Database), with the following keywords and filters: mesothelioma, guidelines, treatment, surgery, chemotherapy, radiotherapy, review, investigational, drugs. Currently different targeted therapies and biologicals are under investigation for MPM. It is important that the molecular biologic research should first focus on mesothelioma-specific pathways and biomarkers in order to have more effective treatment options for this disease. The use of array technology will be certainly an implicit gain in the identification of new potential prognostic or biomarkers or important pathways in the MPM pathogenesis. Probably a central mesothelioma virtual tissue bank may contribute to the ultimate goal to identify druggable targets and to develop personalized treatment for the MPM patients.

Chemotherapy for malignant pleural mesothelioma

OPINION STATEMENT

All MPM patients with a good performance status should be considered for enrollment on clinical trials. With that said, the standard frontline therapy for fit MPM patients remains an antifolate/platinum doublet, based on large, well powered randomized clinical trials that showed not only a survival benefit for antifolate/platinum regimens but also improvements in quality of life and/or symptoms. For less fit patients, single agents can be used as frontline therapy. In the second line setting, there is benefit from retreatment with single agent pemetrexed after prior exposure to that agent, as well as after exposure to other chemotherapeutic agents. Other single chemotherapy agents and combinations are viable options for fit patients who have had relatively long time to progression after their frontline therapy. Additionally, several prognostic scales designed for MPM (CALGB and EORTC) provide additional means to better select patients for frontline and second line chemotherapy.

Phase II study of gemcitabine plus docetaxel as second-line treatment in malignant pleural mesothelioma: a single institution study

OBJECTIVE

The combinations of cisplatin-pemetrexed and cisplatin-gemcitabine are considered the standard systemic therapy for malignant pleural mesothelioma (MPM), which is a rapidly progressive tumor. The purpose of the present study is to evaluate the efficacy, safety, and clinical benefit of the gemcitabine plus docetaxel regimen in the second-line treatment of this disease.

PATIENTS AND METHODS

A total of 37 patients with MPM were treated with the combination of docetaxel (80 mg/m) and gemcitabine (1000 mg/m) on day 1 and 14 of a 28-day cycle. The regimen was repeated for a maximum of 6 cycles or until disease progression or unacceptable toxicity.

RESULTS

There was partial response of the disease in 7 patients (18.9%), whereas it remained stable in 23 patients (62.2%) and progressed in 7 patients (18.9%). The median time to disease progression was 7 months (range: 5.8-8.2 months) with a mean survival of 16.2 months (range: 13-19.3 months).

CONCLUSION

The biweekly administration of docetaxel and gemcitabine, along with granulocyte colony-stimulating factor support, constitutes a safe, tolerable, and convenient regimen for the treatment of MPM, suggesting that this combination may be a viable option, especially in previously treated patients.

[Guidelines of the European Respiratory Society and the European Society of Thoracic Surgeons for the management of malignant pleural mesothelioma]

恶性胸膜间皮瘤（malignant pleural mesothelioma, MPM）是一种罕见肿瘤，但发病率正逐渐上升，且预后较差。2008年，欧洲呼吸学会（European Respiratory Society, ERS）和欧洲胸外科医师学会（European Society of Thoracic Surgeons, ESTS）特别工作组召集各方专家计划制定MPM诊治经验及更新指南。

为了使MPM得到及时准确的诊断，专家推荐对患者实施胸腔镜检查，有手术禁忌和胸腔粘连的病例除外。约10%的病例采用标准染色方法无法获得满意的结果。因此我们推荐在胸膜活检的基础上，采用特异性免疫组化标志物。由于目前缺乏一个统一的、切实有效的分期系统，我们推荐应用最新的TNM分期，并且提出三个阶段的治疗前评估。在MPM的治疗中，患者的体力状态评分和组织亚型是目前唯一的、具有重要临床价值的预后因素。在临床试验中，应对其它潜在因素进行初步探讨并予以报道。MPM对化疗高度耐受，仅有少数患者可接受根治性手术。本文对新的治疗方法和策略进行了综述。

目前由于最佳综合治疗的资料有限，适合采用多种方案联合治疗策略的患者应被纳入专业机构的前瞻性试验中。

Chemotherapy and radiotherapy for mesothelioma

Previously considered to be rare, malignant pleural mesothelioma (MPM) is a highly aggressive tumor with an increasing incidence linked to asbestos exposure, its main etiological factor. MPM is also a very important issue because patients have usually a short survival (median <12 months) despite current treatments. Moreover an optimal treatment for MPM is not defined yet, even if ERS/ESTS experts recently provided clear and up-to-date guidelines on MPM management. These guidelines on chemotherapy and radiotherapy for mesothelioma, as well as new therapeutic developments, are presented in this chapter.

[Second-line therapy in patients with malignant pleural mesothelioma. A French retrospective study (2005-2006)]

BACKGROUND

The role of second-line chemotherapy (SLC) has still not been established in malignant pleural mesothelioma (MPM) but SLC is increasingly used because many patients are still fit at the time of the progression of the disease.

METHODS

In this retrospective study, the authors reviewed their experience with SLC in pemetrexed-pretreated patients with MPM at two French thoracic oncology units (institut Gustave-Roussy, Villejuif, and hôpital d'Instruction des Armées Percy, Clamart).

RESULTS

Between January 2005 and December 2006, 84 consecutive patients with progressing MPM after pemetrexed chemotherapy were enrolled. Forty-four patients received an SLC. There were 30 men and 14 women. The median age was 58 years (range: 34 to 76 years). Most patients had a performance status (PS) less than or equal to 1 (82%) and an epithelial histological subtype (91 %). The median time to progression (TTP) after first-line chemotherapy was 6.1 months. The SLC was a pemetrexed therapy in 21 patients and a new regime in 20 patients (gemcitabine alone or with oxaliplatin). The other three patients were enrolled in a phase I study. According to the Recist criteria, a partial response was observed in four patients and the disease was stabilised in six patients after SLC. The median TTP after SLC was 3.8 months. The median survival was 12.2 months (range: 2 to 72 months). Four of these 44 patients then received third-line (4.8 %) and two received fourth-line therapy (2.4 %).

CONCLUSIONS

This experience indicates the feasibility of administering SLC in patients with MPM who are healthy at the time of the progression of the disease. The optimal treatment has not been defined to date and prospective trials are needed.

Gemcitabine combined with oxaliplatin in pretreated patients with malignant pleural mesothelioma: an observational study

Background

The aim of this study was to investigate the efficacy and safety of oxaliplatin ± gemcitabine in patients with diffuse malignant pleural mesothelioma (MPM) pretreated with pemetrexed.

Methods

The study enrolled consecutive patients with relapsed MPM, all of them pretreated with a platin-pemetrexed-based chemotherapy. Oxaliplatin 80 mg/m² was administered as monotherapy or in combination with gemcitabine 1000 mg/m² given on day 1 and 8. Cycles were repeated every 21 days. The primary endpoints were response rate and disease control rate. Secondary endpoints included overall survival (OS), time to tumour progression (TTP), progression-free survival (PFS), time to treatment failure (TTF), and toxicity.

Results

Between February 2005 and September 2007 29 patients (median age: 65.0 years, World Health Organisation (WHO) performance status: 0–3) were enrolled. The follow-up period encompassed 5.4 to 97.4 weeks (median: 24.3 weeks). Out of these 29 patients, 15 were treated in second, 10 in third, 3 in fourth and 1 in fifth line, respectively. The majority of the patients received the combination oxaliplatin and gemcitabine (n = 25 vs. 4; 86.2 vs. 13.8%).

The median overall survival (OS) was 71.7 weeks (30.6–243.3 weeks), whereas survival from the start of oxaliplatin/gemcitabine-treatment was 24.3 weeks (5.4–97.3 weeks). Median time to tumour progression (TTP) was 9.3 weeks (3.0–67.6 weeks).

Partial response (PR) was observed in 2 patients (6.9%), stable disease (SD) for at least three courses of treatment in 11 patients (37.9%). Thus, disease control rate was 44.8%, whereas 16 of 29 patients exhibited progressive disease (55.2%).

The toxicity profile was favourable, with no WHO grade 4-toxicities, only few dose-reductions were performed due to non-symptomatic haematotoxicities (neutropenia, thrombopenia). Mild WHO grade 2 neurotoxicity was seen in 6 patients.

Conclusion

Pemetrexed-pretreated patients with progressive MPM may benefit from a consecutive chemotherapy with oxaliplatin and gemcitabine without significant toxicity.

The efficacy and safety of weekly vinorelbine in relapsed malignant pleural mesothelioma

Malignant pleural mesothelioma (MPM) is a rapidly progressive invariably lethal tumor. Treatment options remain limited and the outcome in relapsed disease is poor warranting new therapeutic options. Following our previous experience in the first-line setting, we conducted a phase 2 open-label non-comparative study to assess the safety and efficacy of weekly vinorelbine chemotherapy, each cycle consisting of 30 mg/m(2) for 6 weeks, in patients with previous exposure to chemotherapy. In 63 individuals with relapsed MPM who had not received previous vinorelbine, we observed an objective response rate of 16% and an overall survival of 9.6 months (95% confidence interval 7.3-11.8 months). The main grade III/IV toxicity observed was neutropenia and toxicity was similar to weekly vinorelbine when used in the first-line setting. Weekly vinorelbine appeared to have a reasonable response rate with an acceptable toxicity profile in the second-line treatment of MPM. Its use should be prospectively evaluated in a randomised trial in the first or second-line therapy of MPM.

Phase III trial of pemetrexed plus best supportive care compared with best supportive care in previously treated patients with advanced malignant pleural mesothelioma

PURPOSE

This multicenter, phase III study compared overall survival (OS) of second-line pemetrexed plus best supportive care (BSC) versus BSC alone in patients with advanced malignant pleural mesothelioma (MPM). Secondary end points included response rate, progression-free survival (PFS), time to tumor progression (TTP), time to treatment failure (TTF), and toxicity.

PATIENTS AND METHODS

Patients with relapsed MPM after first-line chemotherapy were randomly assigned to receive pemetrexed 500 mg/m(2) plus BSC (P+BSC) every 21 days or BSC alone.

RESULTS

The study enrolled 243 patients (123 on P+BSC arm and 120 on BSC arm). Median OS time was not significantly different between the arms (8.4 months for P+BSC and 9.7 months for BSC; P = .74). Cox regression modeling suggested a trending survival benefit for patients who responded to first-line therapy. Time-to-event measures significantly favored P+BSC (median PFS, TTP, and TTF). Partial response was achieved in 18.7% and 1.7% of patients in P+BSC and BSC arms, respectively (P < .0001), and a disease control rate (partial response plus stable disease) was achieved in 59.3% and 19.2% of patients in P+BSC and BSC arms, respectively (P < .0001). Use of postdiscontinuation chemotherapy was significantly greater among BSC patients compared with P+BSC patients (51.7% v 28.5%, respectively; P = .0002), with more BSC patients receiving pemetrexed (18.3% v 3.3%, respectively; P = .0001). Postdiscontinuation therapy was initiated earlier for BSC than P+BSC patients (median time to initiation, 4.3 v 15.7 months, respectively; log-rank P < .0001). Chemotherapy was well tolerated, with expected modest (4% to 7%) grade 3 and 4 hematologic toxicities.

CONCLUSION

Second-line pemetrexed elicited significant tumor response and delayed disease progression compared with BSC alone in patients with advanced MPM. Improvement in OS was not seen in this study, possibly because of the significant imbalance in postdiscontinuation chemotherapy between the arms.

Gemcitabine and vinorelbine in pemetrexed-pretreated patients with malignant pleural mesothelioma

BACKGROUND

Pemetrexed-cisplatin chemotherapy is the standard of care in the first-line treatment of unresectable malignant pleural mesothelioma (MPM). Second-line cytotoxic therapy is considered for a growing group of patients, but the optimal treatment has not been defined to date. Gemcitabine and vinorelbine have shown activity in the first-line setting. The objective of this study was to evaluate the activity and toxicity of the gemcitabine-vinorelbine combination in pemetrexed-pretreated patients with MPM.

METHODS

From January 2004 to September 2006, 30 consecutive patients who were pretreated with pemetrexed with or without a platinum-derivative were enrolled. Gemcitabine 1000 mg/m(2) and vinorelbine 25 mg/m(2) were administered intravenously on Days 1 and 8 every 3 weeks. Treatment was repeated for a maximum of 6 cycles or until progression or unacceptable toxicity.

RESULTS

A partial response was observed in 3 patients (10%; 95% confidence interval [CI], 2.1-26.5%), and 10 patients (33.3%; 95% CI, 17.3-52.8%) had stable disease after treatment. Overall, 13 patients (43.3%; 95% CI, 25.5-62.6%) achieved disease control. The median time to progression was 2.8 months (range, 0.6-12.1 months), and the median survival was 10.9 months (range, 0.8-25.3 months). Hematologic toxicity was acceptable, with grade 3 or 4 neutropenia occurring in 11% of patients and thrombocytopenia occurring in 4% of patients; no case of febrile neutropenia was observed. Nonhematologic toxicity generally was mild.

CONCLUSIONS

The gemcitabine and vinorelbine combination was moderately active and had an acceptable toxicity profile in pemetrexed-pretreated patients with MPM. The role of second-line treatment in MPM needs to be evaluated in prospective trials in large series of patients who are stratified according to previous treatment and prognostic factors.

Multidisciplinary treatment of malignant pleural mesothelioma

The incidence of malignant pleural mesothelioma (MPM) is increasing worldwide, and is predicted to peak in the next 10-20 years. Difficulties in MPM diagnosis and staging, especially of early disease, have thwarted the development of a universally accepted therapeutic approach. Single modality therapies (surgery, radiotherapy, chemotherapy) have generally failed to significantly prolong patient survival. As a result, multimodality treatment regimens have been developed. Radical surgery with extrapleural pneumonectomy and adjuvant treatments has become the preferred option in early disease, but the benefits of such an aggressive approach have been questioned because of significant treatment-related morbidity and mortality. In the past few years, there have been several major advances in the management of patients with MPM, including more accurate staging and patient selection, improvements in surgical techniques and postoperative care, novel chemotherapy regimens with definite activity such as antifolate (pemetrexed or raltitrexed)-platinum combinations, and new radiotherapy techniques such as intensity-modulated radiation therapy. Induction chemotherapy followed by surgery and adjuvant radiotherapy has shown promising results. A number of molecular alterations occurring in MPM have been reported, providing broader insights into its biology and leading to the identification of new targets for therapy. However, currently available treatments still appear to have modest results. Further studies are needed to provide evidence-based recommendations for the treatment of early and advanced stages of this disease.

Current therapies for malignant pleural mesothelioma

Mesothelioma is a highly lethal tumor derived from mesothelial cells, and its global incidence is increasing because of widespread exposure of numerous individuals to asbestos in the last 50 years. Mesothelioma is largely untreatable with any of the therapeutic modalities. Recently, a novel multitargeted antifolate pemetrexed has shown promising activity against malignant pleural mesothelioma, producing response rates of up to 40% when used in combination with cisplatin. In a large phase III study, use of a combination of pemetrexed and cisplatin was associated with significantly improved survival time and with greater antitumor activity compared with cisplatin alone. This combination also gave a significant response rate of approximately 50% in patients with epithelioid malignant pleural mesothelioma. These clinical benefits of pemetrexed-cisplatin doublet have changed the perception of mesothelioma chemotherapy. Other combinations, including gemcitabine in combination with cisplatin, have also shown encouraging response rates. Prognosis depends on gender, clinical stage of the tumor, histological subtype, platelet count, leukocyte counts, and performance status. Radiotherapy can palliate mesothelioma patients with chest pain, and has been indicated to be of benefit for the prevention of malignant seeding along the tract of a chest tube or needle biopsy. Trimodality treatment using extrapleural pneumonectomy, radiation and chemotherapy has shown promising therapeutic value. The development of chemotherapeutic regimens and the favorable outcomes of trimodality have led to new combined modality trials. In Japan, multicenter national trials against mesothelioma will begin in the near future.

Management options for malignant pleural mesothelioma: clinical and cost considerations

Malignant pleural mesothelioma (MPM) is a resistant form of lung cancer that is often related to prior asbestos exposure. While surgical resection and radiotherapy techniques have been refined in recent years, neither has been proven to significantly extend patient survival compared with untreated controls. Until the release of pemetrexed in 2004, even combination chemotherapy regimens often resulted in a response rate of <20%. A recent phase III trial documented a 41.3% response rate for cisplatin plus pemetrexed. In the future, new multimodality regimens featuring novel targeted therapies directed against molecular targets, such as the vascular endothelial growth factor, hold the greatest promise for improved outcomes in MPM. The standard radiographic assessment of response to MPM therapy remains a poor surrogate for clinically relevant endpoints such as median survival. Furthermore, it is not currently known whether aggressive multimodality treatment for MPM will improve survival or quality of life above and beyond symptomatic care. Ongoing clinical trials are comparing chemotherapy and surgery with supportive care in an effort to define the role of different therapies in MPM. MPM treatment is a costly public health issue; after efficacy is proven, additional studies are needed to measure the cost effectiveness of MPM treatment regimens.

Pemetrexed as Second-Line Treatment in Malignant Pleural Mesothelioma after Platinum-Based First-Line Treatment

INTRODUCTION

Pemetrexed is active as first-line treatment of malignant pleural mesothelioma. The objective was to evaluate its activity as second-line treatment.

METHODS

Patients had disease progression of malignant pleural mesothelioma after previous platinum-based regimens without pemetrexed. Treatment was pemetrexed alone or pemetrexed combined with carboplatin. Pemetrexed dosing was 500 mg/m and carboplatin was AUC (area under the curve) 5 once every 3 weeks.

RESULTS

Thirty-nine patients were included: 28 Danish patients received pemetrexed (three patients received pemetrexed as third-line treatment), whereas 11 Norwegian patients received pemetrexed plus carboplatin. Most patients were men (90%), had epithelial subtype (85%), and International Mesothelioma Interest Group stages III to IV (77%). Median age was 62 years (range, 30-77). The median number of treatment courses was six (range, 1-23). Common Toxicity Criteria grade 3 to 4 toxicity occurred only with respect to leukocytopenia (pemetrexed: 14% of patients; pemetrexed plus carboplatin: 9%) and thrombocytopenia (pemetrexed: 7%; pemetrexed plus carboplatin: 18%). One patient receiving pemetrexed died of sepsis. Partial response rates were 21% and 18%, the median time to progression was 21 weeks (range, 4-92) and 32 weeks (range, 4-128+), and the median survival was 42 weeks (range, 4-99) and 39 weeks (range, 10-128+) with pemetrexed and pemetrexed plus carboplatin, respectively.

CONCLUSIONS

Pemetrexed was generally well tolerated with noteworthy activity in malignant pleural mesothelioma after previous platinum-based treatment and may be considered for second-line treatment.

Efficacy and safety of first- or second-line irinotecan, cisplatin, and mitomycin in mesothelioma

BACKGROUND

Malignant pleural mesothelioma (MPM) is a rapidly progressive lethal tumor. Treatment options remain limited and the outcome in recurrent disease is poor.

METHODS

A Phase II open-label noncomparative study was conducted to assess the safety and efficacy of the triplet combination irinotecan, cisplatin, and mitomycin-C (IPM) chemotherapy in untreated patients and in those with previous exposure to chemotherapy.

RESULTS

In 62 patients an objective response rate of 25% was observed. In the first-line setting progression-free survival measured 6.4 months (95% confidence interval [CI]: 4.5-7.3) and overall survival was 10.8 months (95% CI: 7.9-13.7). In the second-line setting progression-free survival was 7.3 months (95% CI: 3.4-11.2) and overall survival was also 7.3 months (95% CI: 4.8-9.8). Psychosocial well-being improved during chemotherapy and the main toxicity observed was neutropenia (40%).

CONCLUSIONS

IPM appeared to have a reasonable response rate with an acceptable toxicity profile in the first- and second-line treatment of MPM.

A retrospective analysis of malignant pleural mesothelioma patients treated either with chemotherapy or best supportive care between 1990 and 2005 A single institution experience

The aim of this study was to investigate the efficacy and safety profile of chemotherapy (CT) compared to best supportive care (BSC) in patients with histopathologically confirmed diffuse malignant pleural mesothelioma (DMPM). A total of 161 patients between 1990 and 2004 treated either with CT (109 patients) or BSC (52 patients) depending on patients choice were evaluated in this analyses. Chemotherapy protocols included a combination of cisplatin, mitomycin C and recombinant interferon alpha 2a (CM-In), or cisplatin, mitomycin C and ifosfamide (CMI), or cisplatin and gemcitabine (CG). We found a significant difference in the median survivals of the patients with CT compared to BSC, 11.3 months versus 8.0. Objective response rate was 28/109 (25.7%) with 3.7% of complete response rate. Stable disease rate was 39/109 (35.8%). There was a significant difference between median survivals of patients with objective response (17 months) and median survivals of patients with progressive diseases (6 months) and also with stable diseases (16 months). There was a significant difference between the stable disease and the progressive disease. Stages 3 and 4 patients of epithelial cell type having received chemotherapy live longer than those not having received chemotherapy (12 months versus 4). There was no significant difference between the survivals of the different chemotherapy regimens. The toxicity with CT regimens were mild and well-tolerated. We conclude that CT prolongs survival compared to BSC in patients with DMPM. Survivals of patients with objective response prolong considerably with CT compared BSC. We observed that stages 3 and 4 patients with epithelial cell type got benefit from CT. Especially, of epithelial cell type stages 1 and 2 should receive multimodal treatment.

Biology and management of malignant pleural mesothelioma

Malignant mesothelioma is an aggressive tumour, with a poor prognosis and an increasing incidence as a result of widespread exposure to asbestos. The results of the treatments available are poor. Surgery and radiotherapy have a limited role in highly selected patients and systemic therapy is the only potential treatment option for the majority of patients. Despite some definite activity of the novel antifolates such as pemetrexed and raltitrexed, the results, even in combination with platinating agents, are still modest, with a median survival of approximately one year. The better understanding of the biology of mesothelioma makes the assessment of a number of targeted agents particularly interesting. Unfortunately, the targeted agents imatinib, gefitinib, erlotinib and thalidomide have been shown to be ineffective in unselected patients. Studies with anti-angiogenesis agents are ongoing. An improvement of the knowledge of major molecular pathways involved in malignant mesothelioma is needed in order to define proper targets for the systemic treatment of this disease.

Therapeutic potential of antisense oligodeoxynucleotides to down-regulate thymidylate synthase in mesothelioma

Malignant mesothelioma is an aggressive tumor of the serosal surfaces of the lungs, heart, and abdomen. Survival rates are poor and effective treatments are not available. However, recent therapeutic regimens targeting thymidylate synthase (TS) in malignant mesothelioma patients have shown promise. We have reported the use of an antisense oligodeoxynucleotide targeting TS mRNA (antisense TS ODN 83) to inhibit growth of human tumor cells. To test the potential for antisense targeting of TS mRNA in treatment of malignant mesothelioma, we assessed and compared the effects of antisense TS ODN 83 on three human malignant mesothelioma cell lines (211H, H2052, and H28) and human nonmalignant mesothelioma cells (HT29 colorectal adenocarcinoma, HeLa cervical carcinoma, and MCF7 breast tumor cell lines). We report that ODN 83 applied as a single agent effectively reduced TS mRNA and protein in malignant mesothelioma cell lines. Furthermore, it inhibited malignant mesothelioma growth significantly more effectively than it inhibited growth of nonmalignant mesothelioma human tumor cell lines: a difference in susceptibility was not observed in response to treatment with TS protein-targeting drugs. In malignant mesothelioma cells, antisense TS both induced apoptotic cell death and reduced proliferation. In nonmalignant mesothelioma cells, only reduced proliferation was observed. Thus, antisense TS-mediated induction of apoptosis may be the basis for the high malignant mesothelioma sensitivity to antisense targeting of TS. Further preclinical and clinical study of TS antisense oligodeoxynucleotides, alone and in combination with TS-targeting chemotherapy drugs, in mesothelioma is warranted.

Management of Malignant Pleural Mesothelioma

Malignant mesothelioma is increasing in incidence globally and has no known cure. Its unique clinical feature of local infiltration along tissue planes makes it a difficult neoplasm to manage. There have been few randomized controlled trials regarding treatment options, although these have increased in recent years, and results are eagerly awaited. This article summarizes important advances in the management of mesothelioma, especially diagnostic and therapeutic aspects.