A review of chemotherapy trials for malignant mesothelioma

Cytoreductive surgery combined with intraoperative hyperthermic intrathoracic chemotherapy for stage I malignant pleural mesothelioma

BACKGROUND

Malignant pleural mesothelioma (MPM) is a disease mostly confined to the thoracic cavity. Untreated, the median survival is <1 year. Cytoreductive surgery combined with intraoperative hyperthermic intrathoracic chemotherapy is used to kill residual tumor cells on the surface of the thoracic cavity while having limited systemic side effects.

METHODS

From August 1998 to August 2001, 22 patients with stage I MPM were included in this study. Two patients were irresectable at operation because of extrathoracic tumor growth. Twenty procedures were performed. After cytoreduction, a perfusion was performed with cisplatin and doxorubicin at 40 degrees C to 41 degrees C for 90 minutes. Adjuvant radiotherapy was given to surgical scars and drainage tracts.

RESULTS

There was no perioperative mortality, but significant morbidity was seen in 13 patients (65%), including bronchopleural fistula, diaphragm rupture, wound dehiscence, persistent air leakage, and chylous effusion. No hair loss or leucopenia was noticed. The median follow-up was 14 months. The median survival (Kaplan-Meier) was 11 months, with a 1-year survival of 42%. A favorable pharmacokinetic ratio was observed for both cisplatin and doxorubicin.

CONCLUSIONS

Cytoreductive surgery combined with hyperthermic intrathoracic chemotherapy for stage I MPM is feasible. However, this treatment is accompanied by considerable morbidity. Survival data were less encouraging.

Combination of raltitrexed and oxaliplatin is an active regimen in malignant mesothelioma: results of a phase II study

PURPOSE

The aim of this open-label phase II study was to evaluate the activity of raltitrexed (Tomudex; AstraZeneca, Cergy, France) and oxaliplatin combination therapy in patients with diffuse malignant pleural mesothelioma. PATIENT AND METHODSs: Fifteen pretreated and 55 chemotherapy-naive patients (median age, 60 years; World Health Organization performance status of < or = 2) were enrolled. Most patients (66%) had advanced disease. Patients received raltitrexed 3 mg/m2 followed by oxaliplatin 130 mg/m2 every 3 weeks.

RESULTS

Twenty-four patients (34%) were classified as having a poor prognosis. In the overall study population, 14 patients (20%) had a partial response, and 32 patients (46%) had stable disease. The symptomatic response rates were as follows: shortness of breath, 36%; pain, 30%; activity, 23%; appetite, 21%; and asthenia, 20%. Median time to disease progression was 18 weeks (95% confidence interval [CI], 13 to 22 weeks). In chemotherapy-naive patients, median survival was 31 weeks (95% CI, 23 to 40 weeks) from the start of treatment and 49 weeks (95% CI, 40 to 52 weeks) from diagnosis of mesothelioma. In pretreated patients, median survival was 44 weeks (95% CI, 24 to 40 weeks) from the start of treatment and 226 weeks (95% CI, 63 to 292 weeks) from the diagnosis of mesothelioma. Overall 1-year survival was 26% (95% CI, 15.5% to 36.4%), survival was 22% (95% CI, 10.9% to 33.2%) in chemotherapy-naive patients and 40% (95% CI, 15.2% to 64.8%) in pretreated patients. Hematologic toxicity was mild, and there was no alopecia. The most common adverse events were asthenia, nausea/vomiting, and paraesthesia, and no treatment-related deaths were reported.

CONCLUSION

The raltitrexed and oxaliplatin combination is an active outpatient regimen in malignant mesothelioma and has an acceptable tolerability profile.

Phase II trial of ZD0473 as second-line therapy in mesothelioma

A phase II, open-label, non-comparative, multicentre trial of the platinum analogue ZD0473 as second-line therapy for pleural mesothelioma has been completed. The objectives were to evaluate the activity and tolerability of ZD0473 in patients with relapsed or progressive disease who had received one prior chemotherapy regimen. Forty-seven patients were recruited onto the trial, all aged > 18 years with a life-expectancy > 12 weeks, and World Health Organization (WHO) performance status < or = 2. A starting dose of 120 mg/m2 was administered to 14 patients, six of whom subsequently had their dose escalated to 150 mg/m2. Thirty-three patients received a starting dose of 150 mg/m2. In total, 147 treatment cycles were administered (median number of cycles 3 [range 1-6]). The main toxicity of ZD0473 was haematological (thrombocytopenia) and the most common non-haematological adverse event was nausea. There was no clinically significant nephro-, neuro-, or oto-toxicity. Of the 43 patients evaluable for response, 12% had a minor response (defined by a reduction in lesion size > or = 10% but < 50%), 44% had stable disease, 40% had disease progression, and two patients died before an objective response could be assigned. Median time to progression and death in evaluable patients was 77 days (95% confidence interval [CI]: 44, 105 days) and 203 days (95% CI: 165, 277 days), respectively. In conclusion, although ZD0473 demonstrated a manageable tolerability profile, no complete or partial responses were seen in second-line treatment of mesothelioma. This trial also demonstrates that clinical trials in second-line mesothelioma patients are feasible.

Inactivation of p16INK4a expression in malignant mesothelioma by methylation

The molecular mechanisms of oncogenesis in mesothelioma involve the loss of negative regulators of cell growth including p16(INK4a). Absence of expression of the p16(INK4a) gene product is exhibited in virtually all mesothelioma tumors and cell lines examined to date. Loss of p16(INK4a) expression has also been frequently observed in more common neoplasms such as lung cancer as well. In a wide variety of these malignancies, including lung cancer, p16(INK4a) expression is known to be inactivated by hypermethylation of the first exon. In a survey of ten mesothelioma cell lines, one cell line (NCI-H2596) was identified as possessing loss of p16(INK4a) gene product following gene methylation. This methylation in these mesothelioma cells could be reversed, resulting in re-expression of p16(INK4a) protein, following the treatment of the cells with cytidine analogs, which are known inhibitors of DNA methylation. In previous clinical trials in mesothelioma, the cytidine analog dihydro-5-azacytidine (DHAC) has been found to induce clinical responses in approximately 17% of patients with mesothelioma treated with this drug, including prolonged complete responses. In addition, we identified evidence for methylation of p16(INK4a) in three of 11 resected mesothelioma tumor samples. When both cell lines and tumors are combined, inactivation of p16(INK4a) gene product expression following DNA hypermethylation was found in four of 21 samples (19%). We are further exploring the clinical significance of inhibition of methylation in mesothelioma by cytidine analogs. This may provide a potential treatment target in some mesothelioma tumors by inhibition of methylation.

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.

Intrapleural infusion of activated macrophages and gamma-interferon in malignant pleural mesothelioma: a phase II study

STUDY OBJECTIVES

Intrapleural immunotherapy has shown some activity in patients with malignant mesothelioma. We conducted a multicentric pilot phase II study to evaluate the tolerance and the activity of intrapleurally infused autologous human activated macrophages (AM Phi) in patients with stage IA, IB, and IIA malignant pleural mesothelioma (MPM).

DESIGN

AM Phi derived from in vitro monocyte culture were infused into the pleura of patients every week for 8 consecutive weeks. Each infusion was followed 3 days later by an intrapleural injection of 9 millions units of gamma-interferon (gamma-IFN) in an attempt to prolong the in vivo activation of infused AM Phi. Response was assessed by CT scan and thoracoscopy when possible. If the patient's disease progressed after AM Phi treatment, an additional treatment was left to the choice of the investigator.

PATIENTS

Nineteen patients with histologically proven stage IA, IB, or IIA MPM were enrolled. Two patients were excluded before any AM Phi infusion because of complications impeding infusion. Seventeen patients were actually treated. After completion of the AM Phi cellular therapy, 10 patients were treated with chemotherapy as their diseases progressed.

RESULTS

The overall response rate of patients actually treated was 14%. When including the two patients enrolled but not treated, the overall response "in intention to treat" was 11%; two patients had a partial response, with a duration of response of 30 months and 3 months, respectively. One patient, who could not be evaluated by thoracoscopy because of pleural symphysis, is still alive without any clinical or radiologic sign of disease 69 months after treatment. No major adverse effects were observed during the infusion of either AM Phi or gamma-IFN, and there was no interruption of treatment because of toxicity. However, symphysis was observed in 7 of 14 patients who received the complete treatment. The median survival of patients actually treated, including those who received chemotherapy after AM Phi, was 29.2 months.

CONCLUSION

Combined infusion of AM Phi and gamma-IFN was well tolerated in patients with MPM; however, it had limited antitumor activity.

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.

Multimodality treatment of diffuse malignant pleural mesothelioma

Diffuse malignant pleural mesothelioma (DMPM) is a challenging disease in all of its aspects, from presentation and diagnosis to staging and treatment. Single-modality therapy was the initial approach to this disease. It generally has not been effective in changing the natural history of DMPM. As a result, multimodality regimens involving surgery with radiation, chemotherapy, or immunotherapy delivered regionally or systemically have been evaluated. Randomized controlled studies comparing various strategies are lacking and, thus, the debate continues regarding the effectiveness of different treatment approaches.

Multicenter randomized controlled trial of the management of unresectable malignant mesothelioma proposed by the British Thoracic Society and the British Medical Research Council

Malignant mesothelioma is almost invariably fatal. The incidence of the disease is rising rapidly in many countries, and there is no generally accepted standard treatment for patients with unresectable disease. According to current British Thoracic Society (BTS) guidelines, patients should be treated with active symptom control (ASC), involving (1) regular follow-up in a specialist clinic; (2) structured assessments of physical, psychological and social problems with appropriate action; (3) rapid involvement of additional specialists; and (4) parallel nursing support. Although many nonrandomized studies have reported tumor responses to anticancer chemotherapy, few have studied palliation and it is not known whether chemotherapy prolongs survival or provides clinically worthwhile palliation with acceptable toxicity when given in addition to ASC. We therefore plan to conduct a multicenter randomized controlled trial comparing (1) ASC alone, (2) ASC plus mitomycin vinblastine and cisplatin (MVP), and (3) ASC plus vinorelbine (N; Navelbine, Pierre Fabre Oncology, Winchester, UK). We chose these chemotherapy regimens because they have been shown in nonrandomized studies to provide good symptom control as recorded by patients. The outcome measures are overall survival, palliation of symptoms, performance status, analgesic usage, toxicity, quality of life, tumor response, and recurrence/progression-free survival. In a preliminary feasibility study, we are assessing the acceptability of the trial design to patients and the suitability of two standard quality-of-life instruments in mesothelioma. Data will help us to decide the final details of the large multicenter trial.

Cytoreductive surgery and intraoperative hyperthermic intrathoracic chemotherapy in patients with malignant pleural mesothelioma or pleural metastases of thymoma

STUDY OBJECTIVES

No established curative treatment is available for pleural thymoma metastases and malignant pleural mesothelioma (MPM). Recently, peritoneal malignancies have been treated by cytoreductive surgery and intraoperative hyperthermic intracavitary perfusion chemotherapy (HIPEC). We investigated the feasibility and safety of this multimodality treatment in the thoracic cavity.

DESIGN

Patients with pleural thymoma metastases or early-stage MPM were enrolled in a feasibility study. Morbidity, recurrence, and survival rates were recorded.

SETTING

The Netherlands Cancer Institute.

PATIENTS

Three patients with pleural thymoma metastases and 11 patients with pleural mesothelioma were treated.

INTERVENTIONS

Cytoreductive surgery and intraoperative hyperthermic intrathoracic perfusion chemotherapy (HITHOC) with cisplatin and adriamycin were performed. The mesothelioma patients received adjuvant radiotherapy on the thoracotomy wound and drainage tracts.

MEASUREMENTS AND RESULTS

Morbidity and mortality rates were 47% and 0%, respectively. Reoperation was necessary in four cases. Severe chemotherapy-related complications were not observed. A solitary mediastinal and a contralateral pleural thymoma recurrence were successfully treated by radiotherapy and a contralateral HITHOC procedure. All thymoma patients were alive and free of disease after a mean follow-up period of 18 months. After a mean follow-up period of 7.4 months, nine mesothelioma patients are alive. Two mesothelioma patients died of contralateral pleural and peritoneal recurrent disease, while one patient is alive with locoregional recurrence.

CONCLUSIONS

Cytoreductive surgery and HITHOC with cisplatin and adriamycin is feasible in patients with pleural thymoma metastases and early-stage MPM, and is associated with acceptable morbidity rates. Early data on locoregional disease control are encouraging, and a phase II study will be conducted.

Phase II trial of a single weekly intravenous dose of ranpirnase in patients with unresectable malignant mesothelioma

PURPOSE

A multicenter phase II trial of ranpirnase (Onconase; Alfacell Corp, Bloomfield, NJ) as a single agent was conducted to further assess the safety and clinical efficacy of this novel antitumor ribonuclease. Patients with unresectable and histologically confirmed malignant mesothelioma (MM) were eligible.

PATIENTS AND METHODS

One hundred five patients with Eastern Cooperative Oncology Group performance status 0 to 2 were enrolled onto the study. Thirty-seven percent of patients had not responded to prior chemotherapy. The primary end point of the study was survival. Tumor responses and time to progression were also assessed. The Cancer and Leukemia Group B (CALGB) prognostic group criteria were used to define a treatment target group (TTG). Both the intent-to-treat (ITT) and the TTG populations were analyzed for survival.

RESULTS

Median survival times of 6 months for the ITT and 8.3 months for the TTG populations were observed. The 1- and 2-year survival rates were 34.3% and 21.6% for ITT, respectively, and 42% and 26.8% for TTG, respectively. Among the 81 patients assessable for tumor response, four had partial responses, two had minor regressions, and thirty-five experienced stabilization of previously progressive disease. Patients with responses and stable disease demonstrated markedly prolonged survival. Ranpirnase was well tolerated in the majority of patients, and there were no drug-related deaths.

CONCLUSION

Ranpirnase demonstrated activity and a tolerable toxicity profile in patients with unresectable MM. The prognostic value of the CALGB groups was confirmed.

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.

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.

A phase II study of combined intravenous and subcutaneous interleukin-2 in malignant pleural mesothelioma

A total of 29 previously untreated patients with histologically proven malignant pleural mesothelioma, with an ECOG score of < or = 2 and UICC stage I-II disease, were enrolled between May 1994 and October 1996. On days 1 and 2, 18 x 10(6) IU/day of rIL-2 was administered by continuous intravenous infusion, and 6 x 10(6) IU/day of rIL-2 by subcutaneous injection on days 5--20 inclusive of a 42-day cycle. Further treatment was administered if no radiological disease progression was demonstrated. A total of 29 patients were assessable for toxicity and 25 for response, and 49 cycles of IL-2 were administered with a median of one per patient (range, < 1-4). Toxicity included mild fever, nausea and vomiting, and skin rashes, < grade II. Three patients failed to complete one cycle of treatment because of toxicity and one died of disease before response evaluation. Two patients achieved a partial response (8%, 95% CI 1-26%) surviving 18.1 and 18.7 months from diagnosis. A total of 11 patients (44%, 95% CI 24-65%) with stable disease had a median survival of 13.6 months (range 6.5-33.8). The median survival was 8.6 months (range 3.7-34.5) for the 12 patients with progressive disease (48%, 95% CI 28-69%). This regimen of rIL-2 is well tolerated and shows limited activity in mesothelioma.

Multi-targeted antifolate (MTA): pharmacokinetics of intraperitoneal administration in a rat model

AIMS

LY 231514 or MTA is a multi-targeted antifolate which has been used as an anticancer drug. It is an analogue of folic acid which has shown antitumour activity against various malignancies, particularly mesothelioma and colon cancer. For cancers with peritoneal surfaces extension, the advantage of intraperitoneal chemotherapy over intravenous chemotherapy administration is the high drug concentration that can be achieved locally. Using a rat model, this study was designed to compare the pharmacokinetics and tissue adsorption of intraperitoneal vs intravenous MTA.

METHODS

Sprague-Dawley rats were randomized into three groups according to dose and route of delivery of chemotherapy (10 mg/kg: intravenous; 10 mg/kg: intraperitoneal; 100 mg/kg: intraperitoneal). During the course of the experiment, peritoneal fluid and blood were sampled using a standardized protocol. At the end of the 3 hour procedure the rats were sacrificed, all urine was extracted and selected tissue samples were taken. One additional rat was studied over a 6 hour period for each group. The concentration of MTA in all samples was determined by high performance liquid chromatography (HPLC).

RESULTS

When MTA was delivered at 10 mg/kg the area under the curve (AUC) of the peritoneal fluid was significantly higher with intraperitoneal administration (10 778 microg/mlxmin) compared to intravenous administration (454 microg/mlxmin) (P<0.0001). This represents a 24-fold increase in exposure for tissues at peritoneal surfaces after intraperitoneal administration. The AUC ratio (AUC peritoneal fluid/AUC plasma) was 40.8 for intraperitoneal delivery as opposed to 0.014 for intravenous delivery (P=0.0063). The AUC ratio for intraperitoneal MTA at 100 mg/kg was 19.2. The half-life of MTA in the peritoneal fluid after intraperitoneal infusion was approximately 2 hours. There was a significant difference in MTA concentration in the mesenteric nodes and the abdominal wall (P=0. 0036 and 0.0017) and in the kidneys (P=0.0122) when intraperitoneal and intravenous administration were compared. Other tissue samples did not demonstrate any difference in drug concentration.

CONCLUSION

These experiments demonstrated that the exposure of peritoneal surfaces to MTA is significantly increased with intraperitoneal MTA administration. Due to the high likelihood of microscopic residual disease after resection of intra-abdominal malignancies, clinical studies to evaluate intraperitoneal MTA may be indicated.

Phase II study of intravenous Doxil in malignant pleural mesothelioma

Twenty-four patients with pleural mesothelioma received 50 mg/m2 of Doxil every four weeks. At follow-up, the disease had stabilized in 43% percent of patients and had progressed in 57%. No objective responses were observed. Estimated median survival of all patients was 37 weeks. Major toxicities were erythrodysesthesia of hands and feet and myelosuppression. No cardiac toxicity was observed. We concluded that Doxil at this dosage and schedule is inactive against pleural mesothelioma.

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.

Management of malignant pleural mesothelioma: a critical review

Malignant mesothelioma remains a uniformly fatal disease and best supportive care continues to be the standard treatment. Neither chemotherapy nor surgery has been shown to prolong survival. Radiotherapy is not curative but is useful for prophylaxis against needle-track metastases and for symptom palliation. Combinations of therapies have been tried but most studies were uncontrolled and selection bias makes the results impossible to interpret. The combination of extrapleural pneumonectomy, chemotherapy, and radiotherapy attracted much interest, but the subsequent results were disappointing in a highly selected group of patients. Randomized controlled trials are desperately needed to provide definitive information on experimental treatments. It is also important to develop better measures of disease response and to assess quality of life issues in clinical trials. If patients are to receive therapies other than palliation, they should only do so in the setting of randomized controlled trials under approved protocols.

Environmental asbestos exposure and mesothelioma

Epidemiologic studies of mesothelioma have focused primarily on occupational exposures to asbestos. Nonoccupational exposure to asbestos can be grouped into three main categories: paraoccupational (familial), neighborhood, and true environmental exposures. Elevated mesothelioma rates not attributable to occupational exposures have been observed in asbestos mining and manufacturing areas. Asbestos is one of the most dangerous environmental carcinogens because of the small dose known to cause mesothelioma and the rapid lethality of the disease once it develops. Further research is needed to characterize the contribution and risk profile for environmental asbestos and mesothelioma, and for the development of public health policy.

Mesothelioma: new concepts in diagnosis and management

Malignant pleural mesothelioma is an uncommon, but no longer rare, cancer that is frequently difficult to diagnose and poorly responsive to therapy. Because of the difficulties distinguishing mesothelioma from metastatic adenocarcinoma and reactive pleural inflammation, thoracoscopy or open lung biopsy are usually required to obtain adequate samples for pathologic evaluation. Staging of mesothelioma remains a controversial area. Because none of the six staging systems used in the past was found to be predictive, a TNM-based staging system was recently proposed and is awaiting universal acceptance. Generally perceived as a death sentence, this cancer is associated with a median survival of 9 months from the time of diagnosis in most series, but newer therapeutic strategies show promise for improved and even long-term survival in select cases. Randomized trials are awaited to determine if the improvements in survival reported are not simply due to patient selection.

In vitro sensitivity of normal human mesothelial and malignant mesothelioma cell lines to four new chemotherapeutic agents

In this study, we used four human mesothelioma cell lines (M14K, M24K, M25K and M38K), one transformed human mesothelial cell line (MeT-5A) and one primary mesothelial culture (UPL) to test for in vitro sensitivity to docetaxel, paclitaxel, SN-38 [an active metabolite of irinotecan (CPT-11)] and gemcitabine, as single agents. Subconfluent cell cultures were treated with 2x10(-9), 5x10(-9), 10(-8), 2x10(-8) and 5x10(-8) M concentrations of each drug for 48 h. The sensitivity was measured in terms of cell viability using the Trypan blue exclusion method. All four drugs were potent inhibitors of mesothelioma cell growth, but cell lines from different patients diverged in their sensitivity to the individual agents. In most cases docetaxel, paclitaxel and SN-38 were more potent killers of mesothelioma cells than gemcitabine. The induction of DNA damage was investigated using the Comet assay; cells from two cell lines (M14K and M25K) were treated with subtoxic 10(-8) M concentrations of each drug for 4, 24 and 48 h. Each of the agents caused a slight increase in DNA single-strand breaks at a concentration of 10(-8) M.

Medical examination for asbestos-related disease

There are millions of workers whose exposure to asbestos dust prior to the implementation of asbestos regulation and improved control measures places them at risk of asbestos-related disease today. In addition, workers are still being exposed to significant amounts of asbestos, when asbestos materials in place are disturbed during renovation, repair, or demolition. Given the continued presence of asbestos-containing materials in industrial, commercial, and residential settings throughout the U.S., a sizeable population remains at risk of asbestos-related disease. This article reviews the health effects associated with exposure to asbestos and delineates the steps necessary for the comprehensive screening and clinical assessment for asbestos-related disease, in order to assist physicians in identifying and preventing illness associated with exposure to asbestos among their patients.

Advances in the treatment of malignant pleural mesothelioma

Malignant pleural mesothelioma is a neoplasm that is commonly fatal and for which there are no widely accepted curative approaches. Mesothelioma is unresponsive to most chemotherapy and radiotherapy regimens, and it typically recurs even after the most aggressive attempts at surgical resection. Multimodality approaches have been of some benefit in prolonging survival of very highly selected subgroups of patients, but they have had a relatively small impact on the majority of the patients diagnosed with this disease. As the incidence of pleural mesothelioma peaks in the United States and Europe over the next 10 to 20 years, new therapeutic measures will be necessary. This review will discuss the roles of chemotherapy, radiotherapy, surgery, and combined modality approaches in the treatment of pleural mesothelioma, as well as scientific advances made in the past decade that have led to the development of experimental techniques, such as photodynamic therapy, immunotherapy, and gene therapy, that are currently undergoing human clinical trials. These promising new avenues may modify the therapeutic nihilism that is rampant among clinicians dealing with mesothelioma.

High-dose methotrexate in combination with interferons in the treatment of malignant pleural mesothelioma

Twenty six patients with pleural mesothelioma of UICC stage I-IV excluding M1 disease (46% of whom had stage I disease and 38% stage III disease) were treated intravenously with high dose MTX (3 g) and calcium folinate rescue three times at intervals of 2 weeks and three times at intervals of 3 weeks. Natural interferon (IFN)-alpha (3 MIU days 2-10) and recombinant IFN-gamma1b (50 microg m(-2) on days 2, 6 and 10) were injected subcutaneously after each MTX dose. At the end of MTX treatment the IFNs were continued as maintenance therapy until disease progression. Seven partial responses were observed among 24 patients evaluable for response (response rate 29%, 95% confidence interval 13-51%). Median duration of response was 10 months (range 3-24 months). Median survival was 17 months and 1-year and 2-year survival rates 62% and 31% respectively. The toxicity of the chemo-immunotherapy was acceptable. Treatment was stopped in one patient who developed grade IV neurological toxicity. MTX dose reductions were rare (two patients with grade 1-2 renal toxicity). The combination of high dose MTX and IFN-alpha and IFN-gamma is active against malignant pleural mesothelioma and well-tolerated. The survival rates are encouraging.

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.

Pleural mesothelioma

The increasing incidence of malignant pleural mesothelioma (MPM), better knowledge of its pathogenesis with a strong implication of asbestos fibers, and some promising therapeutic results have led to a new interest in the management of patients with this disease. The diagnosis of MPM is easier because of new immunohistochemical markers that recognize the mesothelial cells with good specificity and sensitivity on pleural biopsy samples ideally obtained by thoracoscopy. Moreover, this endoscopic procedure allows the physician to make the diagnosis of MPM at an early stage, which is the key of the therapeutic management of this disease. If radiotherapy is necessary in preventing the malignant seeding after pleural procedures in patients, the lack of comparative studies did not show the superiority of a given treatment against another. A new international staging of the disease, however, allows physicians to discriminate several groups of patients for such comparative studies--in particular, for testing the efficacy of intrapleural therapy, e.g., cytokines--for early-stage MPM and multimodal management, i.e., extrapleural pneumonectomy, radiotherapy, and chemotherapy for more advanced diseases, has led to prolonged survival in carefully selected patients. To reach this target, all patients must be enrolled in protocols. The usual pessimism for the management of patients with malignant pleural mesothelioma is over.

Raltitrexed (Tomudex) in combination with platinum-based agents and/or anthracyclines: preliminary results of phase I clinical trials

Three ongoing, dose-escalation, phase I studies are evaluating the combination of raltitrexed with oxaliplatin or anthracyclines (with and without cisplatin). In study 1, patients with advanced solid tumours received 2.0-3.75 mg/m2 raltitrexed, followed 45 min later by 85-130 mg/m2 oxaliplatin (2-h infusion) every 3 weeks. In study 2, patients with advanced oesophageal or gastric adenocarcinoma received 2.0-3.0 mg/m2 raltitrexed with 50 mg/m2 intravenous (i.v.) epirubicin and 60 mg/m2 i.v. cisplatin every 3 weeks. In study 3, patients with advanced or metastatic gastric cancer received 2.5-3.5 mg/m2 raltitrexed followed by 30-60 mg/m2 i.v. doxorubicin every 3 weeks. In all studies, raltitrexed was given as a 15-min infusion. All the combinations evaluated were administered in convenient 3-weekly schedules and were generally well tolerated. Recommended doses for raltitrexed and oxaliplatin are the same in combination as for single-agent use, i.e. 3.0 mg/m2 raltitrexed and 130 mg/m2 oxaliplatin. The recommended dose of raltitrexed in combination with cisplatin and epirubicin is 2.5 mg/m2. No dose-limiting toxicities were observed during co-administration of the full single-agent doses of raltitrexed and doxorubicin (3.0 mg/m2 and 60 mg/m2, respectively); dose escalation is continuing. Preliminary efficacy results were encouraging, particularly for the combination of raltitrexed and oxaliplatin in patients with mesothelioma and advanced colorectal cancer. Preliminary data from these phase I studies suggest that the combination of raltitrexed with platinum-based agents and/or anthracyclines may represent useful regimens for the treatment of patients with advanced cancer. Further studies are required to identify the most effective combinations of raltitrexed with both established and new anticancer agents.