Trimetrexate in malignant mesothelioma: A Cancer and Leukemia Group B Phase II study

Systemic Chemotherapy with Pemetrexed and Cisplatin for Malignant Peritoneal Mesothelioma: A Single Institution Experience

Background and aims

Primary malignant peritoneal mesothelioma is a rare malignancy with an unfavorable prognosis. Pemetrexed has proven effective in the treatment of malignant mesothelioma, alone or in combination with platinum agents. In the present study, chemo-naïve patients were evaluated for the efficacy and safety of the pemetrexed-cisplatin combination.

Methods

Six patients with diffuse peritoneal mesothelioma were treated with 6 cycles of pemetrexed (500 mg/m2) and cisplatin (75 mg/m2). Chemotherapy was administered on an outpatient basis every 3 weeks.

Results

Complete response was observed in 2 patients (33%) and partial response was observed in 3 patients (50%). The estimated median overall survival was 24 months and the estimated median time to disease progression was 9.5 months. The regimen was well tolerated.

Conclusions

Though our data reflect a small sample size, pemetrexed plus cisplatin accomplished a particularly high clinical benefit rate on chemo-naïve patients. Free full text available at www.tumorionline.it

Validation of Progression-Free Survival as a Surrogate Endpoint for Overall Survival in Malignant Mesothelioma: Analysis of Cancer and Leukemia Group B and North Central Cancer Treatment Group (Alliance) Trials

PURPOSE

The aim of this study was to investigate whether progression-free survival (PFS) can be considered a surrogate endpoint for overall survival (OS) in malignant mesothelioma.

MATERIALS AND METHODS

Individual data were collected from 15 Cancer and Leukemia Group B (615 patients) and 2 North Central Cancer Treatment Group (101 patients) phase II trials. The effects of 5 risk factors for OS and PFS, including age, histology, performance status (PS), white blood cell count, and European Organisation for Research and Treatment of Cancer (EORTC) risk score, were used in the analysis. Individual-level surrogacy was assessed by Kendall's tau through a Clayton bivariate Copula survival (CBCS) model. Summary-level surrogacy was evaluated via the association between logarithms of the hazard ratio (log HR)-log HR_OS and log HR_PFS-measured in R² from a weighted least-square (WLS) regression model and the CBCS model.

RESULTS

The median PFS for all patients was 3.0 months (95% confidence interval [CI], 2.8-3.5 months) and the median OS was 7.2 months (95% CI, 6.5-8.0 months). Moderate correlations between PFS and OS were observed across all risk factors at the individual level, with Kendall's tau ranging from 0.46 to 0.47. The summary-level surrogacy varied among risk factors. The Copula R² ranged from 0.51 for PS to 0.78 for histology. The WLS R² ranged from 0.26 for EORTC and PS to 0.67 for age.

CONCLUSIONS

The analyses demonstrated low to moderate individual-level surrogacy between PFS and OS. At the summary level, the surrogacy between PFS and OS varied significantly across different risk factors. With a short postprogression survival and a moderate correlation between PFS and OS, there is no evidence that PFS is a valid surrogate endpoint for OS in malignant mesothelioma. The Oncologist 2017;22:189-198Implications for Practice: For better disease management and for more efficient clinical trial designs, it is important to know if progression-free survival (PFS) is a good surrogate endpoint for overall survival in malignant mesothelioma. With a relatively large database of 17 phase II trials and 716 patients from Cancer and Leukemia Group B and North Central Cancer Treatment Group, we conducted statistical analyses and found that there is no evidence to suggest that PFS is a valid surrogate endpoint for OS for malignant mesothelioma. Future research work is needed to find alternative surrogate endpoints for OS.

Prolonged response to pemetrexed-based chemotherapy in a patient with peritoneal mesothelioma: a case report and review of the literature

Peritoneal mesothelioma is a rare tumor typically presenting with ascites and associated with occupational asbestos exposure with a latency period of 20–40 years. Intensive multi-modality approach combining cytoreductive surgery, intraperitoneal chemotherapy and possibly radiotherapy can be considered, but otherwise the prognosis is rather poor. Palliative chemotherapy may be an option in these rare cases. However, no approved systemic treatment exists for peritoneal mesothelioma. We present here a patient with peritoneal mesothelioma who was treated with the combination of pemetrexed with cisplatin shortly after the failure of hyperthermic intraperitoneal chemotherapy. The patient experienced durable partial response to the treatment, resolution of ascites, and returned to his normal daily life activities. With the exception of palliative chemotherapy in case of patients in good condition, therapeutic options in patients with peritoneal mesothelioma are currently very limited. The combination of pemetrexed and cisplatin can lead to long-term control in selected patients.

Malignant pleural mesothelioma: medical treatment update

Malignant pleural mesothelioma (MPM) is a disease usually unaffected by current therapeutic strategies, but for the majority of patients, the use of systemic chemotherapeutic drugs remains the only therapeutic option available. During the past 15-20 years, many phase II and a few phase III clinical trials have studied a large variety of drugs such as anthracyclines, alkylating agents, platinum compounds, taxanes, vinka alkaloids, and antifolates as single agents and in combination, with the aim to increase responses and survival. The combination of pemetrexed and cisplatin tested in the largest phase III randomized trial of malignant pleural mesothelioma ever conducted has become the current standard of care. New targeted therapeutic approaches with a variety of anti-growth factor drugs are currently undergoing investigation worldwide.

Malignant peritoneal mesothelioma-Results from the International Expanded Access Program using pemetrexed alone or in combination with a platinum agent

AIM

Peritoneal mesothelioma (PM) has rarely been studied. The Expanded Access Program (EAP) provided access to 109 patients with PM.

METHODS

This was a nonrandomized, open-label study conducted in chemo-naïve or previously treated patients with PM not amenable to curative surgery. Patients received pemetrexed (PEM) 500 mg/m2 alone or with cisplatin (CIS) 75 mg/m2 or carboplatin (CARBO) AUC 5 every 21 days, supplemented with standard vitamin B(12), folate, and dexamethasone.

RESULTS

Response rates (95% CI) for PEM, PEM/CIS, and PEM/CARBO were 12.5% (3.5, 29.0), 20.0% (7.7, 38.6), and 24.1% (10.3, 43.5), respectively. Median survival for PEM was 10.3 months. One-year survival rates for PEM/CIS and PEM were 57.4% (95% CI: 10.3, 100) and 41.5% (95% CI: 4.6, 78.4), respectively, and were not available for PEM/CARBO. Anemia was the most common serious adverse event (6.4%). Neutropenia (34.6%) was the most frequent CTC grade 3 or 4 toxicity reported.

CONCLUDING STATEMENT

PEM with or without a platinum agent was both active and well tolerated in patients with peritoneal mesothelioma.

Single-agent pemetrexed for chemonaïve and pretreated patients with malignant pleural mesothelioma: results of an International Expanded Access Program

INTRODUCTION

Pemetrexed has established efficacy, and is the backbone for chemotherapy in patients with malignant pleural mesothelioma (MPM). An International Expanded Access Program provided >3000 mesothelioma patients with access to single-agent pemetrexed or pemetrexed plus platinum analogs (cisplatin or carboplatin) in 13 countries. In this article, we report the safety and efficacy data of MPM patients who were treated with single-agent pemetrexed (n = 812).

METHODS

Patients with histologically confirmed MPM, not amenable to curative surgery, received pemetrexed (500 mg/m) once (day 1) every 21 days with standard premedication and vitamin supplementation. Investigator-determined response and survival data were recorded at the end of study participation. Myelosuppression data were also collected.

RESULTS

All 812 MPM patients (319 chemonaïve; 493 pretreated) received single-agent pemetrexed (>or=1 dose) and were evaluated for safety. A total of 643 patients (247 chemonaïve, 396 pretreated) were evaluated for efficacy. Of the chemonaïve patients evaluated for efficacy (n = 247), the overall response rate was 10.5%, median time to progressive disease (TTPD) was 6.0 months, and median survival was 14.1 month. Of the pretreated patients evaluated for efficacy (n = 396), the overall response rate was 12.1%, median TTPD was 4.9 months, and the median survival was not estimable due to high censoring. Common terminology criteria grade 3/4 hematologic toxicity was mild in both groups, with neutropenia (<18%) as the main toxicity.

CONCLUSIONS

In the present expanded access program, single-agent pemetrexed demonstrated promising activity in MPM in both chemonaïve and pretreated patients, with TTPD of 6.0 and 4.9 months, respectively, 1-year survival >or=54.7%, and mild hematologic toxicity.

Phase II Trial of Pralatrexate (10-Propargyl-10-deazaaminopterin, PDX) in Patients with Unresectable Malignant Pleural Mesothelioma

BACKGROUND

Several previous clinical trials have shown that malignant pleural mesothelioma is responsive to antifolates. The dihydrofolate reductase inhibitor, pralatrexate, has a favorable toxicity profile, primarily limited to stomatitis, and has demonstrated activity in patients with non-small cell lung cancer. In mesothelioma cell lines and xenografts, pralatrexate demonstrated significant antitumor activity.

METHODS

We conducted this phase II study to determine the response rate of malignant pleural mesothelioma to pralatrexate at a dose of 135 mg/m2 i.v. every 2 weeks. After a protocol amendment, patients were supplemented with vitamin B12 and folic acid at the time of starting therapy.

RESULTS

A total of 16 assessable patients were enrolled. No complete or partial responses were observed. Two patients with epithelioid histology had minor responses. Three other patients remained on study with stable disease for 9, 9, and 48 months. The median time to progression was 3 months. The overall median survival time was 7 months (95% confidence interval: 3.2-16.2 months) and the one-year survival was 31% (95% confidence interval: 15%-65%). Three patients (19%) had grade 2 stomatitis, eight (50%) had grade 3, and one (6%) had grade 4.

CONCLUSIONS

With this particular dose and schedule, pralatrexate as a single agent had no activity in malignant pleural mesothelioma.

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.

The cancer and leukemia group B respiratory committee

The Cancer and Leukemia Group B Respiratory Committee has a 30-year track record of clinical investigation in patients with small-cell lung cancer and non-small-cell lung cancer (NSCLC) and mesothelioma. The most widely recognized contributions of the Committee include the early confirmation of the role of concurrent chemoradiotherapy in LD-SCLC, the effect of combination chemotherapy followed by radiation in stage III NSCLC, the introduction of third-generation agents into concurrent chemoradiation for stage III disease, the prospective demonstration of the benefit of treating older (70 years old) and poorer performance status (performance status = 2) patients with first-line combinations for stage IV disease, and the development of the "Herndon prognostic index" to normalize patient characteristics and outcomes in sequential phase II trials of new agents in patients with mesothelioma. Many other contributions have also emerged from the Committee's clinical trials and correlative science programs. We look forward to making additional critical contributions during future decades of Cancer and Leukemia Group B Respiratory Committee research.

Systemic chemotherapy in the management of malignant peritoneal mesothelioma

AIM

To review available evidence on the efficacy of chemotherapy in malignant mesothelioma of any origin.

METHODS

All original research and review papers related to the role of systemic chemotherapy in the treatment of malignant mesothelioma, published from 1966 through February 2005, were identified through a MEDLINE search of the literature using the following search terms: "mesothelioma", "peritoneal", "chemotherapy", "antifolates", "cancer therapy". This search was supplemented by a manual search of the Proceedings of the Annual Meetings of the American Association for Cancer Research, American Society of Clinical Oncology, and the American Association for Cancer Research (AACR)-European Organization for Research and Treatment of Cancer (EORTC)-National Cancer Institute (NCI) Symposium on New Anticancer Drugs.

RESULTS

Pemetrexed in combination with cisplatin is the first treatment regimen that demonstrates a survival improvement in patients with unresectable malignant pleural mesothelioma. Data from uncontrolled studies suggest similar antineoplastic efficacy in patients with mesothelioma of peritoneal origin. Preliminary results also suggest a possible survival advantage for a combination of cisplatin and raltitrexed as compared to cisplatin alone. Other cytotoxic agents that have shown to be active in this setting include vinorelbine and gemcitabine, either alone or combined with platinum compounds.

CONCLUSION

The pemetrexed-cisplatin combination has become the new standard of care for patients with unresectable malignant mesothelioma. Future strategies shall incorporate these novel agents into multimodality approaches at earlier stages of the disease. Given the low incidence of this disease, encouraging physicians to refer these patients to specialized centers and patients to participate in clinical trials is of utmost importance.

Pemetrexed-cisplatin combination in mesothelioma

Despite the desperate struggle for improvement in the therapy of malignant pleural mesothelioma in previous decades, no standard therapy could be established. Pemetrexed (Alimta), a new multitargeted antifolate, showed significant antitumor activity in combination with cisplatin compared with cisplatin alone in patients with unresectable pleural mesothelioma. Furthermore, this improved efficacy was transformed into a significant symptomatic benefit. These data led to the approval of the drug by the US Food and Drug Administration and recently by the European Medicines Evaluation Agency for this combination in malignant pleural mesothelioma, and consequently founded the first standard of treatment in this disease. This review reflects the development of chemotherapy in malignant pleural mesothelioma, discusses the results of the EMPHACIS trial, and outlines further developments for pemetrexed-containing regimens in malignant pleural mesothelioma.

An overview of chemotherapy for mesothelioma

Mesothelioma is an extraordinarily challenging disease to treat. While numerous clinical trials testing various chemotherapeutic agents have been conducted over the last several decades, only recently have larger studies proven the efficacy of newer chemotherapy regimens. This article reviews the data regarding specific classes of chemotherapeutic agents. The role of treatment in various disease settings and the difficulty in assessing the benefit of that therapy is discussed. Finally, an update is provided on novel therapeutics being testing in mesothelioma.

A phase II study evaluating the cisplatin and epirubicin combination in patients with unresectable malignant pleural mesothelioma

Few chemotherapeutic agents have demonstrated their efficacy in malignant mesothelioma. The cisplatin plus doxorubicin combination has one of the highest response rates. Epirubicin is an anthracyclin, analogous to doxorubicin, with a different toxicologic pattern. As there are no data on the activity of the combination cisplatin plus epirubicin in malignant mesothelioma, the European Lung Cancer Working Party (ELCWP) designed a phase II study with response rate as primary objective. Sixty-nine eligible patients with malignant pleural mesothelioma were centrally registered. The majority of the patients were male (n=59), had a Karnofsky performance status of 80 or more (n=62) and presented with an epithelial histologic subtype (n=43). Median age was 62 years. In nine patients, metastases were documented at the initial work-up, mainly in bone, lung and skin. Three hundred and twenty-four cycles of chemotherapy were administered. The main toxicities were nausea and vomiting, neutropenia and alopecia. Among 63 assessable patients, response rate was 19.0% (95% confidence interval [CI] 9-29%). Median survival was 13.3 months. In multivariate analysis, poor prognostic factors for survival were neutrophil count and CALGB groups 4-6. In conclusion, cisplatin plus epirubicin appears as an effective regimen in malignant mesothelioma, with a favourable toxicity profile. However, it does not demonstrate superior activity to other active regimens in this disease.

Malignant pleural mesothelioma

Malignant pleural mesothelioma is an uncommon tumor; only about 3000 cases are diagnosed annually in the United States. Cases were described early in the 20th century, but their relationship to asbestos exposure was not documented until 1960. Since then, the incidence has appeared to increase, and numerous epidemiologic studies have confirmed that exposure to asbestos in a variety of settings and occupations is the most significant risk factor for the development of malignant pleural mesothelioma. More recently, the oncogenic virus SV40 has also been implicated as a potential etiologic agent. Surgery, radiotherapy, and chemotherapy have each been used in the treatment of mesothelioma, but generally with little impact on survival. New directions in therapy include aggressive multimodality programs for potentially resectable patients and targeted therapies, including antifolates, antiangiogenesis agents, and drugs directed at epidermal growth factor receptor for the majority of patients presenting with unresectable disease.

Current chemotherapeutic treatment of malignant pleural mesothelioma

Malignant pleural mesothelioma is an aggressive malignancy which is almost always fatal; median survival is usually < 1 year. Most patients present with symptoms including pain, dyspnoea, pleural effusions and chest wall masses. Until recently, there has been no effective treatment which can improve symptoms and prolong survival. This article reviews recent developments in the treatment of mesothelioma, particularly advances in drug therapy and the use of the current most active drug combination: pemetrexed and cisplatin. Pemetrexed is a novel antifolate drug with multiple enzyme targets. The combination of pemetrexed and cisplatin demonstrated a survival advantage over cisplatin alone in patients with pleural mesothelioma, and can give symptomatic benefits. This combination has become the standard of care in mesothelioma treatment.

Chemotherapy for malignant pleural mesothelioma: past results and recent developments

This review summarises results of previously conducted clinical trials and subsequently presents data arising from all phase II-III studies on chemotherapy for malignant pleural mesothelioma (MPM) published since the last relevant overview. While response rates exceeding 30% have barely been achieved with established cytotoxic drugs in MPM therapy, novel chemotherapeutic agents and their combinations appear somewhat more promising. This applies especially to the antimetabolites, and in particular to pemetrexed which produced response rates of up to 45% in combination with platinum compounds. Raltitrexed combined with oxaliplatin has also been shown to be effective, and gemcitabine--applied as a single agent or in combination with cisplatin--as well as vinorelbine appear to improve quality of life in patients presenting with MPM. Data can now be more precisely analysed by increasingly implemented randomised studies, applying a standardised staging system, and distinguishing prognostic groups. While chemotherapy for MPM remains a challenging task, important steps have clearly been made in the past years to combat this aggressive disease. Publication of results from a phase III trial of pemetrexed with cisplatin in a peer reviewed journal may soon establish a standard of care.

Capecitabine in malignant mesothelioma: a phase II trial by the Cancer and Leukemia Group B (39807)

PURPOSE

The CALGB performed a phase II multicenter study to evaluate the activity of oral capecitabine in patients with malignant mesothelioma (CALGB 39807).

PATIENTS AND METHODS

Between November 15, 2000 and August 31, 2001, 27 patients with mesothelioma were enrolled in this study. Capecitabine was administered at 2500 mg/m(2) per day divided in two doses for 14 days followed by a seven-day break. Cycles were repeated every 21 days with restaging performed every two cycles and therapy continuing for up to six cycles. One patient withdrew from the study prior to receiving therapy and is removed from further analysis. Eligibility criteria included no prior treatment, PS 0-1 by CALGB criteria and histologically documented mesothelioma.

PATIENT CHARACTERISTICS

gender; male 19 (73%), female seven; median age 70 (range 40-81); histology: epithelial 15 (58%), mixed eight (31%), unclassified three; site of origin pleura, 25 (96%); weight loss in previous six months of more than 10% in seven (27%), symptoms longer than six months in five (19%).

RESULTS

One patient (4%) had a confirmed PR while 10 (38%) achieved SD for 2-6 cycles. Ten patients (38%) had PD as their best response. There were three patients unevaluable for response and two early deaths. Median survival and failure free survival were 4.9 (95% CI 4-10.8) and 2.4 (95% CI 1.5-4.2) months respectively with a one-year survival of 23% (95% CI 11-49%). Grade three or greater toxicities encountered by at least 10% of patients included lymphopenia (12%), fatigue (12%), dehydration (12%) and diarrhea (15%). Three patients (12%) had grade three skin toxicity or hand-foot syndrome. One patient died of treatment related toxicity during cycle one.

CONCLUSION

The antitumor activity of capecitabine is insufficient to warrant further exploration in patients with malignant mesothelioma.

[Malignant mesothelioma--a diagnostic challenge]

Malignant mesothelioma is a rare neoplasm associated, in 80% of the cases, with exposure to asbestos fibres, with a latency period between 20 and 50 years. The treatment is palliative in most cases because of the extension of the disease at the time of diagnosis. Mesothelioma is a resistant tumour to chemotherapy and radiotherapy. Overall survival varies between 4 and 18 months, rarely over 5 years. The authors present a case of a 82-year-old man, ex-sailor, with prostatic neoplasm in hormonal "escape" phase, admitted with cough and dyspnea. The chest radiograph showed extensive right pleural effusion. The diagnostic hypothesis were metastatic, infectious and primitive neoplasm origin. Pleural biopsy revealed epithelial malignant mesothelioma confirmed by thoracoscopy, associated with prolongated occupational exposure to asbestos fibres. Without surgery indication the patient was submitted to chemotherapy with gencitabin and cisplatin associated with pleurodesis. Although he improved clinically, the presence of two malignant neoplasms, a rare situation in clinical practice, is associated with a poor prognosis, especially condicionated by the epithelial malignant mesothelioma in Butchart stage II. Finally, we discussed new differential diagnostic techniques with metastatic adenocarcinoma and target therapies under study.

Experimental therapy of malignant mesothelioma: new perspectives from anti-angiogenic treatments

We reviewed the published literature of clinical studies in malignant mesothelioma (MM), including phase II as well as older single-agent and combination chemotherapy trials with more than 15 patients. While response rates exceeding 30% have been achieved with established cytotoxic drugs in MM therapy, novel chemotherapeutic agents and their combinations appear more promising. This applies especially to the anti-metabolites (i.e. pemetrexed) that produced response rates of up to 45% in combination with platinum compounds. Moreover, agents targeting novel proliferative and survival pathways in MM are developed to improve treatment outcomes. Here, we focused on the role of several angiogenic growth factors in MM biology and the data of MM-oriented studies on angiostatic agents tested in a phase I-II trial. It seems likely that no single treatment modality will be effective by itself. Studies that use combinations of the newer agents, including angiostatic drugs, with chemotherapy, should be conducted.

Chemotherapy for Malignant Pleural Mesothelioma

Malignant pleural mesothelioma is an aggressive malignancy with no known single curative modality. Most patients are candidates for chemotherapy at some point in their treatment, but no standard regimen has been established. Several phase II single-agent and combination chemotherapy studies have been performed over the past 2 decades. Although the true impact of chemotherapy in mesothelioma remains to be determined, agents with consistent antitumor activity include doxorubicin, platinum agents, and antimetabolites. Combination chemotherapy is associated with higher response rates, but not necessarily longer median survivals. Large randomized trials, which are currently ongoing or have been performed in the past few years, will yield important answers in regard to the role of chemotherapy and the efficacy of various single and combination chemotherapy agents. Furthermore, the biologic and genetic studies of mesothelioma have identified several receptor tyrosine kinases that are aberrantly expressed in these tumors. Orally available small molecule inhibitors of several receptor tyrosine kinases have been developed and are now being evaluated in clinical trials.

Phase III study of pemetrexed in combination with cisplatin versus cisplatin alone in patients with malignant pleural mesothelioma

PURPOSE

Patients with malignant pleural mesothelioma, a rapidly progressing malignancy with a median survival time of 6 to 9 months, have previously responded poorly to chemotherapy. We conducted a phase III trial to determine whether treatment with pemetrexed and cisplatin results in survival time superior to that achieved with cisplatin alone.

PATIENTS AND METHODS

Chemotherapy-naive patients who were not eligible for curative surgery were randomly assigned to receive pemetrexed 500 mg/m2 and cisplatin 75 mg/m2 on day 1, or cisplatin 75 mg/m2 on day 1. Both regimens were given intravenously every 21 days.

RESULTS

A total of 456 patients were assigned: 226 received pemetrexed and cisplatin, 222 received cisplatin alone, and eight never received therapy. Median survival time in the pemetrexed/cisplatin arm was 12.1 months versus 9.3 months in the control arm (P =.020, two-sided log-rank test). The hazard ratio for death of patients in the pemetrexed/cisplatin arm versus those in the control arm was 0.77. Median time to progression was significantly longer in the pemetrexed/cisplatin arm: 5.7 months versus 3.9 months (P =.001). Response rates were 41.3% in the pemetrexed/cisplatin arm versus 16.7% in the control arm (P <.0001). After 117 patients had enrolled, folic acid and vitamin B12 were added to reduce toxicity, resulting in a significant reduction in toxicities in the pemetrexed/cisplatin arm.

CONCLUSION

Treatment with pemetrexed plus cisplatin and vitamin supplementation resulted in superior survival time, time to progression, and response rates compared with treatment with cisplatin alone in patients with malignant pleural mesothelioma. Addition of folic acid and vitamin B12 significantly reduced toxicity without adversely affecting survival time.

Advances in the management of malignant mesothelioma

Malignant mesotheliomas are very aggressive tumors that originate from mesothelial cells, which form the serosal lining of the pleura, pericardial, and peritoneal cavities. Finding effective chemotherapeutic treatment for malignant mesothelioma is a challenge. There is no standard treatment because this tumor is relatively resistant to therapy. A resurgence of interest has been expressed in novel therapies and conventional treatments used in different ways. Several treatment modalities have been studied, including chemotherapy, radiotherapy, surgery, and immunotherapy. Chemotherapy can be administered systemically or directly into the pleura. This review presents the results of the most recent trials and highlights the most promising advances in the battle against this aggressive disease.

Phase II study of pemetrexed with and without folic acid and vitamin B12 as front-line therapy in malignant pleural mesothelioma

PURPOSE

This phase II clinical study evaluated the efficacy of pemetrexed for the treatment of malignant pleural mesothelioma (MPM).

PATIENTS AND METHODS

Patients with a histologically proven diagnosis of MPM, chemotherapy-naive measurable lesions, and adequate organ function received pemetrexed (500 mg/m2) intravenously over 10 minutes every 3 weeks. After a protocol change, most patients also received folic acid and vitamin B12 supplementation to improve safety.

RESULTS

A total of 64 patients were enrolled. Nine (14.1%) of the 64 patients had a partial response. The Kaplan-Meier estimate for median overall survival was 10.7 months. Forty-three patients received vitamin supplementation for all courses of therapy, and 21 patients did not. Seven of the nine responders were vitamin supplemented. The median overall survival was 13.0 months for supplemented patients and 8.0 months for nonsupplemented patients. Vitamin-supplemented patients completed more cycles of therapy than nonsupplemented patients (median, six v two cycles, respectively). Grade 3/4 neutropenia (23.4%) and grade 3/4 leukopenia (18.8%) were the most common laboratory toxicities. Fatigue and febrile neutropenia were the most commonly reported nonlaboratory events (grade 3, 6.3%; grade 4, 0.0% each). The incidence of these toxicities was generally lower in the supplemented patients.

CONCLUSION

Single-agent pemetrexed for MPM resulted in a moderate response rate (14.1%) and median overall survival of 10.7 months. Patients supplemented with folic acid and vitamin B12 tolerated treatment better (less toxicity and more cycles of treatment) and had a 5-month greater median overall survival than nonsupplemented patients. These results indicate that patients with MPM could benefit from single-agent pemetrexed treatment combined with vitamin supplementation.

Chemotherapy for malignant pleural mesothelioma

This paper covers the outcome of previously conducted clinical trials on chemotherapy for malignant pleural mesothelioma and presents data from recent phase II and phase III trials. In contrast to conventional cytotoxic drugs, which have barely produced response rates exceeding 30%, recently introduced chemotherapeutic agents and their combinations promise to be more effective. Especially pemetrexed has yielded response rates of up to 45% in combination with platinum compounds. Furthermore, raltitrexed-oxaliplatin has shown promising activity and gemcitabine was found to improve quality of life in patients with malignant pleural mesothelioma when applied as a single agent or in combination with cisplatin. Based on robust phase III study results, pemetrexed-cisplatin may soon be considered with chemotherapy for this aggressive disease.

Chemotherapy for malignant pleural mesothelioma: past results and recent developments

This review summarises the results of previously conducted clinical trials, and subsequently presents data arising from all phase II-III studies on chemotherapy of malignant pleural mesothelioma (MPM) published since the last relevant overview. While response rates exceeding 30% have barely been achieved with established cytotoxic drugs in MPM therapy, novel chemotherapeutic agents and their combinations appear more promising. This applies especially to the antimetabolites, and in particular to pemetrexed that produced response rates of up to 45% in combination with platinum compounds. Raltitrexed combined with oxaliplatin has also been shown to be effective, and gemcitabine-applied as a single agent or in combination with cisplatin-as well as vinorelbine appear to improve the quality of life in patients presenting with MPM. Data can now be more precisely analysed by increasingly implemented randomised studies, applying a standardised staging system, and distinguishing prognostic groups. While chemotherapy for MPM remains a challenging task, important steps have clearly been made in the past years to combat this aggressive disease. The publication of pemetrexed with cisplatin phase III results in a peer-reviewed journal may soon establish a standard of care.

Activity of chemotherapy and immunotherapy on malignant mesothelioma: a systematic review of the literature with meta-analysis

The role of chemotherapy for unresectable malignant mesothelioma is unclear. The aims of the present study were to evaluate the methodological quality of published papers relative to chemotherapy or immunotherapy in malignant mesothelioma and to aggregate, for trials having a similar methodology, the response rates in order to identify the most active chemotherapeutic drugs and regimens. The literature relative to this topic, published between 1965 and June 2001 was reviewed. A methodological qualitative evaluation was performed according to the European Lung Cancer Working Party scale, specifically designed for phase II trials. A study was considered as potentially positive if the upper limit of the 95% confidence interval (CI) of the response rate was greater than 20% and positive if the lower limit of the 95% CI was > 20%. Eighty-three studies (88 treatment arms) were eligible for the systematic review. Fifty-three arms were considered as positive or potentially positive. No statistically significant difference in the methodological quality was observed between negative and positive studies. Studies were aggregated in four groups according to the presence of cisplatin and/or doxorubicin in the treatment regimen. The combination of cisplatin and doxorubicin had the highest response rate (28.5%; P < 0.001). Cisplatin was the most active single-agent regimen. Our systematic qualitative and quantitative overview of the literature suggests that the most active chemotherapeutic regimen, in term of objective response rate, is the combination of cisplatin and doxorubicin and the best single-agent is cisplatin. The combination of these two drugs can be recommended as control arm for future randomised phase III trials.

Phase I clinical and pharmacokinetic study of pemetrexed and carboplatin in patients with malignant pleural mesothelioma

PURPOSE

To determine the maximum tolerated dose (MTD) of pemetrexed and carboplatin given in combination, to derive a recommended dose for phase II studies, and to explore its efficacy. We assessed toxicities and explored the activity of the drug combination exclusively in patients with malignant pleural mesothelioma (MPM). The pharmacokinetics of both agents was investigated.

PATIENTS AND METHODS

Twenty-seven patients (23 male, four female) with MPM were treated on five escalating dose levels. Doses ranged from pemetrexed 400 mg/m(2) (as a 10-minute intravenous infusion), followed by carboplatin area under the plasma concentration-time curve (AUC) 4 mg/mL.min (as a 30-minute intravenous infusion) to pemetrexed 500 mg/m(2), carboplatin AUC 6 mg/mL.min. All patients had a World Health Organization performance status of 1. A total of 163 courses of treatment were administered (median, six; range, one to 10).

RESULTS

The main toxicity was hematologic, particularly neutropenia, although this was characteristically short-lived and caused few clinical problems. The MTD was pemetrexed 500 mg/m(2), carboplatin AUC 6, because three of the five patients treated at this dose level experienced a dose-limiting toxicity. Eight partial responses (in 25 assessable patients) were observed for a response rate of 32%. Seventy percent of patients noticed an improvement in symptoms, usually (84%) after only two courses. Median time to progression was 305 days, and median survival time was 451 days.

CONCLUSION

The MTD was pemetrexed 500 mg/m(2) and carboplatin AUC 6 mg/mL.min. The recommended phase II dose of the combination is pemetrexed 500 mg/m(2) and carboplatin AUC 5 mg/mL.min. The combination is both active and well tolerated in MPM and deserves further exploration.

Malignant mesothelioma: options for management

In the past, there has been a tendency to think of diffuse malignant pleural mesothelioma as one disease in therapeutic terms, regardless of histological type and tumor stage. This does not happen with other tumors, yet it is equally illogical and inappropriate in mesothelioma. As with other tumors, early diagnosis-while the disease is still in stage I, or even at an in situ stage-must be the goal so that therapy can be maximized, particularly if immunotherapy or gene therapy is to be used. Patients with pure epithelial mesothelioma have a better prognosis and respond better to trimodality therapy. Stage I patients who meet fitness criteria should be offered the option of radical surgery in combination with chemotherapy and radiotherapy. Further research is required to determine the optimum neoadjuvant and adjuvant modalities, particularly the timing of individual drugs, use of hyperthermia, and route of administration. The place of immunotherapy and gene therapy as adjunctive treatments also remains to be defined. For example, it may be possible to reduce tumor bulk and perhaps downstage the disease with immunotherapy before radical surgery, if treatment is started early enough. Gene therapy may have a role either preoperatively or in destroying the microscopic disease that remains after radical surgery. These and other combinations of treatment need to be tested in well-designed clinical trials, probably on a multicenter basis (to enroll a sufficient number of patients). Finding the means to improve treatment for sarcomatous and mixed histology mesothelioma remains a challenge. At present, radical surgery does not seem worthwhile for these patients when combined with currently employed chemotherapy and radiotherapy; however, chemotherapy combinations used for treating other sarcomas need to be evaluated as adjunctive therapy before radical surgery is abandoned altogether as a mode of treatment. A collaborative approach involving thoracic surgeons, basic scientists and oncologists, and physicians with experience in treating mesothelioma is essential. Despite its increasing frequency, mesothelioma is still a relatively rare tumor, so treatment should be concentrated in relatively few supraregional centers to maximize expertise and allow innovative treatment combinations to be implemented with the greatest chance of success. Evaluation of new therapeutic approaches will be achieved more rapidly if these supraregional centers collaborate in multicenter trials. The nihilistic approach of simply waiting until the mesothelioma epidemic eventually begins to decline spontaneously in 20 or 30 years is untenable in view of the hundreds of thousands of deaths that will result if no effective treatment is found.

Current therapy for malignant mesothelioma

This review briefly summarizes the results of previous systemic (chemotherapy) and local (surgery and radiotherapy) treatment attempted to date for malignant mesothelioma. The prospects for newer modalities, ie molecular and biologic therapies, are also highlighted, including results of both preclinical and early clinical research.

The emerging role of antifolates in the treatment of malignant pleural mesothelioma

Clinicians have long regarded malignant pleural mesothelioma as a chemoresistant neoplasm and as a result no standard chemotherapy regimen has emerged. Antifolates such as methotrexate are among the most active compounds in mesothelioma, albeit based only on phase II data. Recently two antifolate-based combinations with apparently higher efficacy than older regimens have emerged: the pemetrexed/cisplatin regimen and the raltitrexed/oxaliplatin regimen. In two phase I trials with pemetrexed combined with either cisplatin or carboplatin responses occurred in five of 11 and nine of 29 patients, respectively. In a phase I trial of raltitrexed/oxaliplatin, six of 17 patients (35%) with mesothelioma achieved a partial response. In a phase II trial of raltitrexed/oxaliplatin, 14 objective responses were confirmed in 72 patients (25%) with malignant pleural mesothelioma. Indeed, responses were seen in cisplatin-refractory patients. Based on the promising results from these combination trials, two large phase III studies have begun. The first study was a multicenter, multinational trial sponsored by Eli Lilly and Company, which randomized more than 430 patients with malignant pleural mesothelioma to cisplatin with or without pemetrexed. That trial completed enrollment in February 2001 and is the largest trial ever conducted in mesothelioma. The second trial is being conducted by the European Organization for the Research and Treatment of Cancer (EORTC) and compares cisplatin with or without raltitrexed with planned accrual of 240 patients. In both trials, survival is the main endpoint. These trials will help to define the role of these new antifolates in malignant pleural mesothelioma.

Chemotherapy for malignant mesothelioma: from doxorubicin to vinorelbine

It has been a challenge to find effective chemotherapeutic treatments for malignant mesothelioma. Over the last several decades numerous single-drug and combination regimens have been examined, but no standard treatment with chemotherapy alone has emerged. Possible explanations for this lack of success are the heterogeneity between the different subclasses of mesothelioma and the difficulties experienced in determining responses on computed tomographic (CT) scan. This review will present the results of most chemotherapy trials. An attempt is also been made to overcome the problem of identifying the overall response rate by presenting the median survival time. Other types of response evaluation and guidelines for patient selection are warranted to properly compare chemotherapeutic treatments.

The role of gemcitabine in the treatment of malignant mesothelioma

Gemcitabine is broadly active in a variety of solid tumors, including malignant mesothelioma. In vitro, gemcitabine demonstrates activity against mesothelioma cell lines. The role of single-agent gemcitabine in patients with mesothelioma is unclear, since three phase II trials treated a total of 60 patients and achieved response rates of 0%, 7%, and 31%. The combination of gemcitabine and cisplatin is synergistic against mesothelioma cell lines in vitro. Gemcitabine in combination with cisplatin or carboplatin shows definite activity in phase II trials. The trial by Byrne and colleagues that demonstrated a response rate of 48% established the combination of gemcitabine plus cisplatin as a standard therapy for this disease in the United States. Subsequent multicenter trials have achieved lower response rates of 26% and 16% for this combination. Gemcitabine plus carboplatin also has activity. Future roles for gemcitabine in malignant mesothelioma patients include incorporating a gemcitabine/platinum regimen for neoadjuvant or adjuvant therapy, combining it with other cytotoxic chemotherapy agents such as pemetrexed or vinorelbine, or adding novel cytostatic agents such as the vascular endothelial growth factor (VEGF) inhibitor, bevacizumab, to the gemcitabine and platinating agent combination.

Prognostic factors in diffuse malignant pleural mesothelioma: effects of pretreatment clinical and laboratory characteristics

The aim of this study was to investigate the effects of various pretreatment clinical and laboratory characteristics on the survival of patients with diffuse malignant pleural mesothelioma (DMPM). One hundred histopathologically confirmed DMPM patients were evaluated. Fifty-nine were treated with chemoimmunotherapy while 41 who had refused chemoimmunotherapy received supportive therapy alone. The following pretreatment characteristics were evaluated in both univariate and multivariate Cox regression analyses: age, gender, Karnofsky performance score (KPS), histology asbestos exposure, presence of chest pain, dyspnoea, weight loss, symptom duration, smoking history, disease location, platelet count, haemoglobin, white blood cell (WBC) count, serum lactate dehydrogenase (LDH) and extent of disease (stage). Univariate analysis showed that patients with age > or = 75 years, male gender, smoking history advanced stages above stage I disease, KPS < 70, WBC count > or = 8450 and LDH level > or = 500 IU l(-1) have a worse prognosis. With multivariate Cox regression analyses, age > or = 75 years, advanced stages above stage I disease, KPS < 70 and LDH level > or = 500 IU l(-1) were found to be indicators of a poorer prognosis. In conclusion, in our study each of low performance status, older age, advanced stage disease, high LDH level and prognosis were found to be related.

Malignant pleural mesothelioma

Malignant pleural mesothelioma remains a difficult tumor to treat, much less cure. Currently, the best chance for long-term survival lies with early diagnosis and aggressive surgical extirpation, but given the typically long delay between the onset of symptoms and diagnosis, this is only possible with a high index of suspicion and an aggressive diagnosis workup. Early referral to a tertiary center experienced in the treatment of MPM may be important for several reasons: (1) decreased risk of tumor spread along multiple thoracenesis/biopsy tracts, (2) the availability of specialized pathologic assays for definitive diagnosis, (3) the availability of critical staging modalities (aggressive mediastinoscopy +/- thoracoscopy, MRI scans performed according to specific mesothelioma protocols, and perhaps PET scans), (4) surgical experience with pleurectomy/decortication and/or extrapleural pneumonectomy, that may decrease morbidity and mortality, and (5) the availability of novel adjuvant protocols. Single-modality therapy is unlikely to result in long-term survival. Aggressive surgery is required for optimal debulking, and extrapleural pneumonectomy may offer better local control compared with pleurectomy/ecortication. Delivery of optimal radiation schedules, which may involve large fractions as well as large total doses, is limited by the presence of nearby dose-limiting structures. Current chemotherapy is severely lacking in producing objective responses and improved survival although gemcitabine and IL-2 may be active agents to be combined with radiation and/or other agents. Hyperthermia, photodynamic therapy, intracavitary therapy, and gene therapy are all relatively new techniques under active investigation that should be supported by enrollment in on-going protocols. Predictably, many of these techniques provide greater benefit when used in the setting of adjuvant protocols or minimal residual disease, emphasizing the importance of multimodality therapy.

Gemcitabine for malignant mesothelioma: A phase II trial by the Cancer and Leukemia Group B

PURPOSE

The CALGB conducted a phase II multicenter trial to evaluate the activity of gemcitabine in malignant mesothelioma (CALGB protocol 9530).

PATIENTS AND METHODS

Seventeen patients were accrued between February 1996 and May 1996 and received gemcitabine 1500 mg/m(2) by intravenous infusion over 30 min weekly for 3 weeks, followed by a 1 week break. Eligibility included a performance status of 0-2 by CALGB criteria, and no prior chemotherapy. Nine patients had epithelial cell type and eight had mixed or sarcomatoid cell types. There were 11 cases with measurable disease and six with evaluable disease.

RESULTS

There were no complete or partial responders. Eight patients had stable disease, seven developed progressive disease, and two were not evaluable for tumor response. Two patients had minor responses. Median survival from study entry was 4.7 months (95% CI 3.1-12.9 months); one year survival was 24% (95% CI 10-55%). One patient remains alive at 37 months. There were two early deaths, one from disease progression and one from pneumonia. Toxicity was mild and included anemia, lymphopenia and infection; no patient experienced grades three or four thrombocytopenia.

CONCLUSION

No antitumor activity was observed for single-agent gemcitabine in patients with malignant mesothelioma in this multicenter phase II study.

Combination raltitrexed (Tomudex(R))-oxaliplatin: a step forward in the struggle against mesothelioma? The Institut Gustave Roussy experience with chemotherapy and chemo-immunotherapy in mesothelioma

The aim of this study was to review the experience of the Institut Gustave Roussy in 163 patients with malignant mesothelioma over a 9-year period. Data from seven consecutive prospective trials, four of chemo-immunotherapy and three of chemotherapy were reviewed. The rationale, methods and results of these trials are summarised and discussed. 98 patients were included in four phase II trials of chemo-immunotherapy whose common denominator was a combination of cisplatin and alpha-interferon. The response rate ranged from 15% to 40%. High-dose weekly cisplatin combined with alpha-interferon yielded the highest response rate but the toxicity of this regimen was considered unacceptable. Neither higher doses of alpha-interferon or the addition of mitomycin C or interleukin-2 to the regimen were able to enhance the activity of this combination. 18 patients were included in a paclitaxel-cisplatin phase II trial. The response rate was only 6% (95% confidence interval (CI): 0-24) and toxicity was also significant. This regimen was, therefore, considered ineffective. Of 17 patients with mesothelioma included in a phase I trial that combined raltitrexed and oxaliplatin, 6 (35%) obtained a partial response. Responses were seen even in cisplatin-refractory mesothelioma. Preliminary results of a subsequent ongoing phase II trial using raltitrexed (3 mg/m(2)) and oxaliplatin (130 mg/m(2)) have confirmed this promising activity with a 30% (9/30) response rate (95% CI: 15-49). The tolerance of this outpatient regimen is acceptable (no significant haematological toxicity and no alopecia) and compares favourably with that of our previous regimens. The final results concerning response and survival are required to confirm the efficacy of this combination. The preliminary results of two studies suggest promising activity with the combination of raltitrexed-oxaliplatin in malignant mesothelioma. The efficacy/toxicity ratio of this combination compares favourably with that of our previous chemotherapy and chemo-immunotherapy regimens.

Cisplatin, mitomycin, and interferon-alpha2a combination chemoimmunotherapy in the treatment of diffuse malignant pleural mesothelioma

STUDY OBJECTIVE

To investigate the therapeutic activity and toxicity of combination chemoimmunotherapy with cisplatin, mitomycin, and interferon (IFN)-alpha2a, by comparing the responses in a group of patients with diffuse malignant pleural mesothelioma (DMPM) to the responses in a control group of DMPM patients given supportive care alone.

DESIGN

Patients with histopathologically confirmed DMPM were evaluated for treatment with chemoimmunotherapy.

SETTING

After the initial evaluation, all patients received either chemoimmunotherapy or supportive care from the Osmangazi University Medical Faculty, Department of Chest Diseases.

PATIENTS

Forty-three patients with DMPM received chemoimmunotherapy until the end of the survey; 19 patients were given supportive therapy alone after refusing chemoimmunotherapy.

INTERVENTIONS

Drugs were administered according to the following schedule: IV cisplatin, 30 mg/m2 qd on days 1 and 2; IV mitomycin, 8 mg/m2 on day 1; and subcutaneous IFN-alpha2a, 4.5 million IU twice weekly. The courses were repeated every 4 weeks.

RESULTS

Overall, 232 chemoimmunotherapy cycles were administered. A total of 10 objective responses (ORs) in 43 patients (23%) were assessed, including 2 complete responses (5%), 4 partial responses, and 4 regressions. Seventeen patients had stable disease, and 16 patients had progression. The median survival time was 11.5 months for the 43 patients who received chemoimmunotherapy and 7.0 months for the 19 patients who received supportive therapy alone. The difference in survival times between the chemoimmunotherapy and supportive therapy groups was not significant. However, the median survival time for the patients who had OR was 21.3 months, which is significantly longer than that of the patients who received supportive care alone and that of patients with progressive disease (6 months). The toxicities associated with the treatment schedule of this study were, for the most part, tolerable.

CONCLUSIONS

The drug combination used in this study is moderately effective and well tolerated in patients with DMPM, especially in those who responded to the treatment.

High-dose paclitaxel plus G-CSF for malignant mesothelioma: CALGB phase II study 9234

BACKGROUND

New agents with activity in mesothelioma are sorely needed. The Cancer and Leukemia Group B (CALGB) therefore performed a phase II study of high-dose paclitaxel in patients with malignant mesothelioma who had no prior chemotherapy.

PATIENTS AND METHODS

Thirty-five patients accrued to this multi-institutional phase II study of paclitaxel given as a 24-hour infusion at 250 mg/m2 every three weeks plus filgrastim (G-CSF) 300 mcg subcutaneously days 3-18.

RESULTS

There were three (9%) regressions of evaluable disease. The median survival was five months (95% confidence interval (95% CI): 1.9-9.6 months), the one-year survival rate was 14% and the two-year survival rate was 6%. Toxicity was tolerable with one death from pneumonia (without neutropenia) on day 18 and a 23% rate of grade 4 granulocytopenia.

CONCLUSIONS

The level of activity seen with paclitaxel is similar to that seen in other CALGB trials of the single agents carboplatin, trimetrexate and 5-azacytidine. Future studies of of paclitaxel (at lower doses) in combination with synergistic agents could be considered.