Results of a phase II trial of combined chemotherapy for patients with diffuse malignant mesothelioma of the pleura

Malignant mesothelioma: Advances in immune checkpoint inhibitor and mesothelin-targeted therapies

Malignant mesothelioma is an aggressive cancer with a poor prognosis and limited treatment options. For many years, the only US Food and Drug Administration-approved first-line treatment for unresectable mesothelioma was pemetrexed plus cisplatin. However, the recent approval of nivolumab plus ipilimumab as frontline treatment for patients with pleural mesothelioma marks a significant milestone for the treatment of this disease. In this review, the authors describe recent advances in therapeutic strategies for the treatment of patients with advanced, unresectable mesothelioma, highlighting the emerging use of immunotherapy and mesothelin-targeted therapies for the management of malignant mesothelioma.

Oxaliplatin and Raltitrexed in the Treatment of Inoperable Malignant Pleural Mesothelioma: Results of a Pilot Study

Aims and Background

The treatment of inoperable malignant pleural mesothelioma is a challenge for the oncologist. Available chemotherapy regimens achieve poor results, therefore new agents or combinations are needed. In a phase I study, the combination of oxaliplatin and raltitrexed was shown to be active against malignant pleural mesothelioma. We herein report the results of a pilot study about the treatment of this disease.

Methods

From April 1999 to June 2000, we enrolled 11 chemotherapy-naïve patients with inoperable malignant pleural mesothelioma suitable to receive the following combination chemotherapy: raltitrexed, 3 mg/m2 iv, and oxaliplatin, 130 mg/m2, as a 2-hr infusion every 3 weeks.

Results

Four partial responses, 1 regression of disease (objective response rate, 45%; 95% Cl, 15.6-74.4%), 4 stable diseases and 2 progressions of disease were observed. An improvement in disease-related symptoms was recorded in all responders and in 2 patients with stable disease. Toxicity was mild, with no toxic-related death and only 1 episode of grade 4 neurotoxicity.

Conclusions

We consider the combination promising and worthy of further studies.

Intrapleural hypotonic cisplatin treatment for malignant pleural mesothelioma: in vitro experiments and clinical application

PURPOSE

We studied the inhibitory effects of hypotonic cisplatin on the growth of malignant pleural mesothelioma (MPM) cell lines in vitro, and assessed the effectiveness of intraoperative intrapleural hypotonic cisplatin treatment combined with extrapleural pneumonectomy for patients with this tumor.

METHODS

In the in vitro experiments, mesothelioma cell lines were exposed to various concentrations of cisplatin in either saline solution or distilled water for up to 5 min. After 48 h incubation, we calculated the inhibition of cell growth. In the clinical study, five patients with MPM underwent intraoperative intrapleural hypotonic cisplatin treatment combined with extrapleural pneumonectomy.

RESULTS

The hypotonic cisplatin treatment inhibited cell growth at a significantly greater rate than the isotonic cisplatin treatment. Just 1-5 min exposure to 10 microg/ml of hypotonic cisplatin inhibited growth by more than 80%. Clinically, no recurrence was found in four of the five patients after a median follow-up period of 27 months (range: 16-36 months), although contralateral multiple pulmonary metastases were found in one patient 10 months after surgery.

CONCLUSION

Hypotonic cisplatin treatment is effective against MPM, and should be investigated further.

Treatment with oral etoposide for childhood recurrent ependymomas

In this study the authors retrospectively evaluated the feasibility and effectiveness of prolonged oral etoposide therapy in children with recurrent ependymoma. Twelve ependymoma patients with documented recurrent or persistent disease were treated between May 1998 and October 2003. All patients were treated monthly with oral VP-16 administered at a dose of 50 mg/m2/d for 21 days, with a 7-day interval between cycles, for a planned minimum number of six cycles. Response (complete plus partial) after two cycles occurred in 5 of the 12 patients (41.6%). Response plus stable disease occurred in 10 of the 12 (83.3%), with a median duration of response or stable disease of 7 months (range 4-30). The median survival was 7 months; the 2-year progression-free survival was 16.7%. These results emphasize that oral etoposide is an attractive option for childhood recurrent ependymomas in terms of administration, tolerability, and neuroradiologic response.

Neoadjuvant Chemotherapy Followed by Extrapleural Pneumonectomy in Malignant Pleural Mesothelioma

Purpose

To investigate neoadjuvant chemotherapy with cisplatin and gemcitabine followed by extrapleural pneumonectomy with or without radiation therapy in patients with potentially resectable malignant pleural mesothelioma (MPM).

Patients and Methods

Eligible patients had MPM with clinical stage T1-3, N0-2, M0 disease considered to be completely resectable and a WHO performance status of 0 to 2. Neoadjuvant chemotherapy consisted of three cycles of cisplatin 80 mg/m2on day 1 and gemcitabine 1,000 mg/m2on days 1, 8, and 15, given every 28 days. Surgery had to consist of a complete extrapleural pneumonectomy, including resection of pericardium and diaphragm. Postoperative radiotherapy was to be considered for all patients.

Results

Nineteen patients with MPM were included in this pilot study. According to the European Organization for Research and Treatment of Cancer prognostic score, two patients were in the good prognosis group, and 17 patients were in the poor prognosis group. The response rate to neoadjuvant chemotherapy was 32%. The major toxicity was thrombocytopenia. Extrapleural pneumonectomy was performed in 16 patients with no perioperative mortality. Major surgical complications occurred in six patients, and all were treated successfully. Thirteen patients received postoperative radiotherapy. The median survival time was 23 months. Two patients remain alive and free of disease 41 and 38 months after initiation of therapy.

Conclusion

For patients with potentially operable MPM, the availability of active and well-tolerated chemotherapy regimens, the fact that extrapleural pneumonectomy can be safely performed after neoadjuvant chemotherapy in an experienced center, and the promising results regarding survival in our pilot study warrant further investigation of the role of neoadjuvant chemotherapy in a multimodality strategy.

Malignant mesothelioma

Clinical trials investigating new trends in the treatment of stage I and II malignant mesothelioma have shown both intra-pleural immunotherapy and systemic chemo-immunotherapy to be efficacious. Intra-pleural gamma-interferon (gamma-IFN) therapy was associated with tolerable toxicity and an overall response (ORR) rate of 19%, while treatment with intra-pleural recombinant interleukin-2 (IL-2) was more toxic, but yielded an ORR of 47% in phase I trial and 55% in a phase II study. The association of intravenous cisplatin and subcutaneous alpha-interferon (alpha-IFN) was also associated with an encouraging ORR of 40% and a median survival of 12 months. Treatment with cisplatin, alpha-IFN and mitomycin C was associated with moderate toxicity and an ORR of 21% and a median survival of 12 months. The association of cisplatin, alpha-IFN and IL-2 was, however, extremely toxic and resulted in an ORR of 15%. The majority of patients responding to intra-pleural immunotherapy and systemic chemo-immunotherapy had epithelial type mesothelioma. The most encouraging results obtained from trials investigating systemic chemotherapy were following treatment with cisplatin, 5-fluorouracil, mitomycin C and etoposide, where an ORR of 38% and an overall median survival rate of 16 months were achieved. Toxicity was mainly haematological and tolerable.

Integration of Multimodality Approaches in the Management of Malignant Pleural Mesothelioma

More than half a century after the first descriptions of mesothelioma as a pathologic entity, satisfactory treatment is still elusive. Although relatively uncommon, the incidence of mesothelioma will most likely increase over the next 10-20 years. Advances have been made in understanding the pathogenesis, diagnosis, and staging, but they have not translated into markedly improved survival. Some use palliative treatment as the primary means of therapy even now. On the other hand, a cadre of individuals have studied how surgery, chemotherapy, and radiation therapy affect the disease. Although each individual modality has had limited success by itself, a multimodality approach has been documented to improve survival and quality of life. In addition, intriguing discoveries in immunology and gene profiling and therapy promise hope for further improvement. In this article, we will illustrate the current views on integrating these different approaches and delineate areas of active research.

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.

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 II trial of pegylated-liposomal doxorubicin (Doxil) in mesothelioma

Pegylated-liposomal doxorubicin (Doxil) is a form of liposomal doxorubicin in which the liposomes are coated with methoxypoly(ethylene glycol), resulting in a diminished uptake by the reticuloendothelial system, a longer half-life in blood, and a different toxicity profile than nonpegylated liposomes. A phase II study of Doxil in mesothelioma was performed. The initial dose per course was 55 mg/m2 every 4 weeks with dose modification based on mucositis and hand-foot syndrome (the main limiting toxicities). Treatment was generally well tolerated. Of 73 evaluable treatment courses in 15 patients, toxicities were mild and similar to previous reports, but dose reduction was common. No definite cardiac toxicity was observed. Fourteen patients were evaluable for response; four of the 15 patients treated responded meaningfully. These data suggest that pegylated-liposomal doxorubicin has activity in mesothelioma, and that this treatment is associated with modest toxicity.

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.

Vascular endothelial growth factor is an autocrine growth factor in human malignant mesothelioma

Vascular endothelial growth factor (VEGF), a potent mitogen for vascular endothelium, is expressed in malignant pleural mesothelioma (MM). The present report examines the effect of VEGF on MM growth. Four MM cell lines produced significantly higher VEGF levels than normal mesothelial cells (1946+/-14 pg/ml vs. 180+/-17 pg/ml; p<0.001). In addition, MM cells expressed the tyrosine kinase-related VEGF receptors Flt-1 and KDR. Recombinant human VEGF phosphorylated both Flt-1 and KDR and increased proliferation of all four MM cell lines in a dose-dependent fashion. Neutralizing antibodies against either VEGF, Flt-1 or KDR significantly reduced MM cellular proliferation. In addition, expression of VEGF, Flt-1, and KDR was observed in MM biopsies. Moreover, higher VEGF levels were found in the pleural effusions of MM patients than in the effusions of patients with non-malignant pleural disease (1885.7+/-894.9 pg/ml vs. 266.9+/-180.5 pg/ml; p<0.001). Linear regression analysis showed a significant inverse correlation between serum VEGF levels and MM patient survival (r=0.72; p<0.01). No correlation was found between tumour vessel density and either serum (r=0.26; p=0.42) or pleural effusion (r=0.35; p=0.26) VEGF levels. These results indicate that VEGF, via activation of its tyrosine kinase receptors, may be a key regulator of MM growth. In addition, VEGF production could have an impact on patient survival, not only by promoting tumour angiogenesis but also by directly stimulating tumour growth.

Phase II study of vinorelbine in patients with malignant pleural mesothelioma

PURPOSE

To evaluate the response rate and impact on quality of life of vinorelbine given as cycles of 30 mg/m(2) weekly for 6 weeks to patients with malignant pleural mesothelioma.

PATIENTS AND METHODS

Twenty-nine patients with histologically proven malignant pleural mesothelioma were enrolled (26 male patients and three female patients; median age, 58 years [range, 29 to 77 years]). Seventeen patients had epithelioid tumors, two had sarcomatoid tumors, and 10 had biphasic tumors. The International Mesothelioma Interest Group staging system was used: one patient had stage Ib disease, 10 had stage II disease, eight had stage III disease, and 10 had stage IV disease. Patients were treated with weekly injections of vinorelbine 30 mg/m(2). A cycle consisted of six weekly injections. The new guidelines to evaluate the response to treatment in solid tumors were used. Responses were measured by spiral computed tomography scan.

RESULTS

All twenty-nine patients had measurable disease and were assessed for response. There were seven partial responses (24% [95% confidence interval, 10% to 44%]), 16 patients had stable disease (55%), and six patients had disease progression on therapy (21%). The median number of vinorelbine injections was 12 (range, 2 to 30). Quality-of-life analyses showed a benefit for vinorelbine therapy.

CONCLUSION

Vinorelbine shows promise in the palliation of patients with malignant pleural mesothelioma. The relatively low toxicity of the drug suggests that trials of vinorelbine in combination with other agents should be feasible.

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.