Combined Epirubicin and Interleukin-2 Regimen in the Treatment of Malignant Mesothelioma: A Multicenter Phase II Study of the Italian Group on Rare Tumors

Epirubicin and Gemcitabine as First-Line Treatment in Malignant Pleural Mesothelioma

Malignant pleural mesothelioma represents a rare disease, for which chemotherapy actually remains unsatisfactory. From August 1998 to November 2001, 28 chemo-radio-immunonaive patients were consecutively enrolled in the trial: 22/6 males/females; median age 63 years (range, 45-79); median ECOG PS 1 (range, 0-2). They were treated with epirubicin (100 mg/m2 iv on day 1) plus gemcitabine (1000 mg/m2 iv on days 1 and 8) every 4 weeks for 6 cycles. Patients who responded to chemotherapy (n = 6) were subsequently treated with interleukin-2 (4,500,000 IU) subcutaneously every other day, until progression. A total of 124 epirubicin-gemcitabine cycles were administered (median, 6/patient; range, 2-6). Twenty-six patients were evaluated for toxicity. According to WHO criteria, we observed grade III-IV hematological and gastrointestinal toxicity respectively in 3 patients (11%) and 1 patient (3%). No red cell transfusions were required and no toxic deaths occurred. Two patients (8%) could not be evaluated for response (no therapy performed). According to WHO criteria, the final responses were: partial in 4 patients (14%), stable disease in 19 patients (69%), and progression in 3 patients (10%). In 26 patients, the median survival was 55 weeks (range, 7-222) and median time to progression 30 weeks (range, 4-156). At the time of this writing, no patient is alive. The 1-year survival was 32%, 2-year survival 11%, and 4% at 3 and 4 years. All patients were at stage III, and time to progression was 58 weeks and survival 63.5 weeks, without any toxicity. This multi-center phase II clinical trial showed that epirubicin plus gemcitabine, as a first-line treatment in malignant pleural mesothelioma, has promising activity with a good tolerability profile and symptom palliation. The role of interleukin-2 in maintenance therapy for malignant pleural mesothelioma is encouraging and requires further study.

Immune responses and immunotherapeutic interventions in malignant pleural mesothelioma

Malignant pleural mesothelioma (MPM) is an aggressive, primary pleural malignancy with poor prognosis, hypothesized to originate from a chronic inflammatory state within the pleura. Similar to what has been observed in other solid tumors (melanoma, ovarian and colorectal cancer), clinical and pre-clinical MPM investigations have correlated anti-tumor immune responses with improved survival. As such, a better understanding of the complex MPM tumor microenvironment is imperative in strategizing successful immunotherapies. Herein, we review the immune responses vital to the development and progression of MPM, as well as assess the role of immunomodulatory therapies, highlighting recent pre-clinical and clinical immunotherapy investigations.

Interleukin-2 for the treatment of solid tumors other than melanoma and renal cell carcinoma

Interleukin-2 (IL-2) is a lymphokine produced by T cells whose main function is to stimulate the growth and cytotoxic response of activated T lymphocytes. It has been used to stimulate the immune system for the treatment of multiples tumors. This article is intended to review the reports published from 1990 to 2004 on the IL-2 treatment of tumors other than melanoma and renal carcinoma. A literature search was made in various databases (MEDLINE, EMBASE and BioAssay), focused on IL-2 clinical efficacy in such tumors. A selection was made over 150 publications reporting on administration of IL-2 in multiple tumors: lung carcinoma (small cell and non-small cell), colorectal, gastric, pancreatic, ovarian and breast cancer, sarcomas, hepatocarcinoma, mesothelioma, and brain, urological, and head and neck tumors. IL-2 was mainly used in metastatic disease, associated with other immunotherapy or chemotherapy schedules. We conclude that adjuvant IL-2 may be of value in early stages combined with standard treatment for colon and pancreas cancers. In other neoplasms, the indication for adjuvant IL-2 has been sporadic and does not allow conclusions to be drawn. Assessment of the efficacy of IL-2 combined with chemotherapy as treatment for advanced stages is complex, due to the lack of a control, and the variety of dosages and schemes. The activity of IL-2 in monotherapy or in association with immunotherapy is clinically relevant in hepatocarcinoma, mesothelioma and in malignant overflows as palliative treatment. Randomized trials would be required in order to be able to draw conclusions about its indication in other tumors.

Ribonucleases as a novel pro-apoptotic anticancer strategy: review of the preclinical and clinical data for ranpirnase

Cytotoxic ribonucleases (RNases), such as ranpiranase, represent a novel mechanism-based approach to anticancer therapy. These relatively small proteins selectively attack malignant cells, triggering apoptotic response and inhibiting protein synthesis. Ranpirnase, originally isolated from oocytes of Rana pipiens, is a member of a family of endoribonucleases. The anticancer effects of ranpiranase have been documented in both in vitro and in vivo experimental tumor models. The effects of ranpiranase appear to be selective for cancer cells. Based on Phase I study data, the maximum tolerated dose (MTD) was 960 microg/m2, with the dose-limiting toxicity (DLT) characterized by proteinuria with or without azotemia, peripheral edema, and fatigue. Ranpirnase did not induce myelosuppression, mucositis, alopecia, cardiotoxicity, coagulopathy, hepatotoxicity, or adverse metabolic effects. Phase II tumor-specific trials investigated the activity of ranpirnase in malignant mesothelioma, breast cancer, non-small cell lung cancer, and renal cell cancer. A Phase III randomized study in malignant mesothelioma patients compares the combination of ranpirnase plus doxorubicin to doxorubicin monotherapy.

Intratumoral Poly-N-Acetyl Glucosamine-Based Polymer Matrix Provokes a Prolonged Local Inflammatory Response That, When Combined with IL-2, Induces Regression of Malignant Mesothelioma in a Murine Model

The authors have previously shown that cytokines delivered directly into malignant mesothelioma (MM) tumors can retard tumor growth and mediate tumor regression under certain conditions. In this report the authors compared the efficacy of serial intratumoral injections of three cytokines, GM-CSF, IL-12, and IL-2, to their sustained release using a single injection in a poly-N-acetyl glucosamine gel. IL-2 combined with the polymer gel gave optimal antitumor results when MM tumors were accessible as either subcutaneous deposits or as masses spread throughout the peritoneal cavity. The gel acted not only as a slow-release cytokine depot but also as a trigger for inflammation and recruited several immune cell types to the gel/tumor interface; when combined with IL-2 (but not with GM-CSF or IL-12), it acted as a selective reservoir for infiltrating CD8+ T cells. Hence, the IL-2/gel may provide a microenvironment that allows intratumoral T cells to proliferate and retain their cytolytic functions as they encounter their cognate antigens expressed by tumor cells.

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.

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.

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.

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.

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.