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

Irinotecan or Oxaliplatin: Which is the First Move for the Mate?

OBJECTIVES

The aim of the present review is to discuss the potential link between RAS, BRAF and microsatellite instability (MSI) mutational patterns and chemotherapeutic agent efficacy [Irinotecan (IRI) vs. Oxaliplatin (OXA)], and how this can potentially influence the choice of the chemotherapy backbone.

METHODS

Following a review of the research literature, all pertinent articles published in the core journals were selected for the study. The inclusion criteria regarded relevant clinical and pre-clinical studies on the topic of interest (Relationship of OXA and IRI to KRAS/BRAF mutations and MSI).

RESULTS

Excision repair cross complementation group 1 (ERCC1) expression is inhibited by KRAS mutation, making tumor cells more sensitive to OXA. Results from OPUS, COIN and PRIME trials support that no conclusive data are available for BRAF mutant population because of the small number of patients. Enhanced IRI cytotoxicity to MSI cell lines is due to the participation of some of the mismatch repair (MMR) components in various DNA repair processes and their role in the maintenance of the pro-apoptotic effect of IRI and G2/M cell arrest.

CONCLUSION

OXA and IRI are indispensable drugs for mCRC treatment and their selection must be as careful as that of targeted agents. We suggest taking into consideration the interaction between known genomic alterations and OXA and IRI activity to personalize chemotherapy in mCRC patients.

Emerging therapies in malignant pleural mesothelioma

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

Characteristics and long-term outcomes of advanced pleural mesothelioma in Latin America (MeSO-CLICaP)

Background

Malignant pleural mesothelioma (MPM) is an aggressive tumor, associated with poor prognosis. There is a lack of information about the clinical and pathological features related with survival in the Latin American population.

Methods

The MeSO‐CLICaP registry identified 302 patients with advanced MPM diagnosed and treated between January 2008 and March 2016. The Cox model was applied to determine the variables associated with survival. A random forest tree model was built to predict the response to first‐line chemotherapy among Latin American patients.

Results

The median age was 61.1 years (SD 10.6 years), 191 (63.2%) were men, 65.9% were ever smokers, and 38.7% had previous exposure to asbestos. A total of 237 (78.5%) had epithelioid tumors, and 188 (62.3%) and 114 (37.7%) cases had stage III or IV MPM, respectively. A total of 49 patients (16.2%) underwent pleurectomy, 57 (18.9%) received radiotherapy, and 279 patients received first‐line platinum‐based chemotherapy. The overall response rate to first‐line chemotherapy was 40.4%, progression‐free survival to first‐line treatment was 5.7 months (95% CI 4.9–6.5), and 63 (20.8%) patients had pemetrexed maintenance. The median overall survival was 16.8 months (95% CI 13.0–20.5), and multivariate analysis found that stage (P = 0.013), and pleurodesis (P = 0.048), were independent prognostic factors for first‐line overall survival. The model to predict response to first‐line chemotherapy obtained a 0.98 area under the curve, a sensitivity of 93%, and a specificity of 95% for detecting responders and non‐responders.

Conclusion

This study identifies factors associated with clinical benefit from chemotherapy among advanced MPM Latin American patients, emphasizing the impact of histology and the clinical benefit of chemotherapy on outcomes.

Treatment of Malignant Pleural Mesothelioma: American Society of Clinical Oncology Clinical Practice Guideline

Purpose To provide evidence-based recommendations to practicing physicians and others on the management of malignant pleural mesothelioma. Methods ASCO convened an Expert Panel of medical oncology, thoracic surgery, radiation oncology, pulmonary, pathology, imaging, and advocacy experts to conduct a literature search, which included systematic reviews, meta-analyses, randomized controlled trials, and prospective and retrospective comparative observational studies published from 1990 through 2017. Outcomes of interest included survival, disease-free or recurrence-free survival, and quality of life. Expert Panel members used available evidence and informal consensus to develop evidence-based guideline recommendations. Results The literature search identified 222 relevant studies to inform the evidence base for this guideline. Recommendations Evidence-based recommendations were developed for diagnosis, staging, chemotherapy, surgical cytoreduction, radiation therapy, and multimodality therapy in patients with malignant pleural mesothelioma. Additional information is available at www.asco.org/thoracic-cancer-guidelines and www.asco.org/guidelineswiki .

Medical treatment of malignant pleural mesothelioma relapses

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

Chemotherapy treatment in malignant pleural mesothelioma: a difficult history

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

Network meta-analysis of the efficacy of first-line chemotherapy regimens in patients with advanced colorectal cancer

This network meta-analysis compared the short-term and long-term efficacies of first-line chemotherapy regimens in patients with advanced colorectal cancer (CRC). The 10 regimens included folinic acid + 5-fluorouracil + oxaliplatin (FOLFOX), folinic acid + 5-fluorouracil + irinotecan (FOLFIRI), folinic acid + 5-fluorouracil + gemcitabine (FFG), folinic acid + 5-fluorouracil + trimetrexate (FFT), folinic acid + 5-fluorouracil (FF), irinotecan + oxaliplatin (IROX), raltitrexed + oxaliplatin (TOMOX), folinic acid + tegafur-uracil (FTU), raltitrexed, and capecitabine. Electronic searches were performed in the Cochrane Library, PubMed and Embase databases from inception to June 2017. Network meta-analysis combined direct and indirect evidence to obtain odds ratios (ORs) and surface under the cumulative ranking curves (SUCRA) of different chemotherapy regimens for advanced CRC. Fourteen randomized controlled trails (RCTs) covering 4,383 patients with advanced CRC were included. The results revealed that FOLFOX, FOLFIRI, IROX, and TOMOX all showed higher overall response rates (ORRs) than FF or raltitrexed. Compared with raltitrexed, the aforementioned four regimens also had higher 1-year progression-free survival (PFS) rates. In addition, FOLFOX and FOLFIRI exhibited higher disease control rates (DCRs) and 1-year PFS rates than FF or raltitrexed. Cluster analysis revealed that FOLFOX, FOLFIRI, and TOMOX had better short-term and long-term efficacies. These findings suggest FOLFOX, FOLFIRI, and TOMOX are superior to other regimens for advanced CRC. These three regimens are therefore recommended for clinical treatment of advanced CRC.

Intracellular quantitative detection of human thymidylate synthase engagement with an unconventional inhibitor using tetracysteine-diarsenical-probe technology

Demonstrating a candidate drug's interaction with its target protein in live cells is of pivotal relevance to the successful outcome of the drug discovery process. Although thymidylate synthase (hTS) is an important anticancer target protein, the efficacy of the few anti-hTS drugs currently used in clinical practice is limited by the development of resistance. Hence, there is an intense search for new, unconventional anti-hTS drugs; there are approximately 1600 ongoing clinical trials involving hTS-targeting drugs, both alone and in combination protocols. We recently discovered new, unconventional peptidic inhibitors of hTS that are active against cancer cells and do not result in the overexpression of hTS, which is a known molecular source of resistance. Here, we propose an adaptation of the recently proposed tetracysteine-arsenic-binding-motif technology to detect and quantitatively characterize the engagement of hTS with one such peptidic inhibitor in cell lysates. This new model can be developed into a test for high-throughput screening studies of intracellular target-protein/small-molecule binding.

Inside the biochemical pathways of thymidylate synthase perturbed by anticancer drugs: Novel strategies to overcome cancer chemoresistance

Our current understanding of the mechanisms of action of antitumor agents and the precise mechanisms underlying drug resistance is that these two processes are directly linked. Moreover, it is often possible to delineate chemoresistance mechanisms based on the specific mechanism of action of a given anticancer drug. A more holistic approach to the chemoresistance problem suggests that entire metabolic pathways, rather than single enzyme targets may better explain and educate us about the complexity of the cellular responses upon cytotoxic drug administration. Drugs, which target thymidylate synthase and folate-dependent enzymes, represent an important therapeutic arm in the treatment of various human malignancies. However, prolonged patient treatment often provokes drug resistance phenomena that render the chemotherapeutic treatment highly ineffective. Hence, strategies to overcome drug resistance are primarily designed to achieve either enhanced intracellular drug accumulation, to avoid the upregulation of folate-dependent enzymes, and to circumvent the impairment of DNA repair enzymes which are also responsible for cross-resistance to various anticancer drugs. The current clinical practice based on drug combination therapeutic regimens represents the most effective approach to counteract drug resistance. In the current paper, we review the molecular aspects of the activity of TS-targeting drugs and describe how such mechanisms are related to the emergence of clinical drug resistance. We also discuss the current possibilities to overcome drug resistance by using a molecular mechanistic approach based on medicinal chemistry methods focusing on rational structural modifications of novel antitumor agents. This paper also focuses on the importance of the modulation of metabolic pathways upon drug administration, their analysis and the assessment of their putative roles in the networks involved using a meta-analysis approach. The present review describes the main pathways that are modulated by TS-targeting anticancer drugs starting from the description of the normal functioning of the folate metabolic pathway, through the protein modulation occurring upon drug delivery to cultured tumor cells as well as cancer patients, finally describing how the pathways are modulated by drug resistance development. The data collected are then analyzed using network/netwire connecting methods in order to provide a wider view of the pathways involved and of the importance of such information in identifying additional proteins that could serve as novel druggable targets for efficacious cancer therapy.

Pemetrexed (Alimta®): improving outcomes in malignant pleural mesothelioma

During the past four decades, chemotherapy has failed to demonstrate a consistent clinical benefit for patients with unresectable or recurrent malignant pleural mesothelioma (MPM). Consequently, there has been no standard chemotherapy nor US Food and Drug Administration (FDA)-approved drug for patients with this disease. The introduction of pemetrexed (Alimta, Eli Lilly), a multitargeted antifolate agent, has improved the outlook for patients with mesothelioma by demonstrating a positive impact on quality of life and by prolonging survival. Pemetrexed is the first FDA-approved drug for the treatment of MPM. The combination of cisplatin plus pemetrexed is now the standard of care for the treatment of the disease. Furthermore, supplementation with vitamin B12 and folate has vastly improved the toxicity profile of pemetrexed. This article summarizes historical chemotherapy trials in MPM; discusses key features of clinical trial design for MPM; summarizes the results of a landmark Phase III trial of pemetrexed and cisplatin in MPM; discusses the relative contributions of pemetrexed and cisplatin to the regimen; explains the importance of vitamin supplementation of pemetrexed; and provides direction for future clinical trials in this disease.

Vinorelbine in pemetrexed-pretreated patients with malignant pleural mesothelioma

BACKGROUND

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

METHODS

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

RESULTS

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

CONCLUSIONS

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

The function, mechanisms, and role of the genes PTEN and TP53 and the effects of asbestos in the development of malignant mesothelioma: a review focused on the genes' molecular mechanisms

The malignant mesothelioma is an aggressive form of cancer with a mean survival rate of less than a year. Moreover, environmental exposure to minerals is an important factor in the development of malignant mesothelioma (MM), especially the mineral asbestos, which has a well-documented role in MM, and more recently, the mineral erionite has been proven to be a strong carcinogenic inducer of MM. In addition, the virus simian virus 40 has been implicated as a co-carcinogenic player in MM. However, the molecular mechanisms involved in the pathogenesis of this cancer are still not fully understood. Indeed, it is known that several genes are altered or mutated in MM, among those are p16(INK4A), p14(ARF), and neurofibromatosis type II. Furthermore, TP53 has been reported to be mutated in the majority of the cancers; however, in MM, it is very uncommon mutations in this gene. Also, the PTEN gene has been shown to play an important role in endometrial cancer and glioblastoma, although the role of PTEN in MM has yet to be established. Taken altogether, this review focuses on the historical aspects, molecular mechanisms, interaction with other genes and proteins, and the role of these genes in MM. Lastly, this review questions the cancer theory of the two hits because the functions of both PTEN and TP53 are not fully explained by this theory.

[Malignant pleural mesothelioma: diagnosis and treatment]

Malignant pleural mesothelioma (MPM) is a rare and aggressive tumor issued from the mesothelial surface of the pleural space. A previous exposure to asbestos is the main risk factor of mesothelioma. Clinical signs are most of the time late and unspecific. Chest CT-scan, a key imaging procedure, usually shows a (unilateral) pleurisy associated with pleural nodular thickening. PET-scan associated with CT-scan may help to differenciate MPM from pleural benign tumors but it is not recommended for the diagnosis of MPM, as well as chest resonance magnetic imaging and blood or pleural fluid biomarkers, including soluble mesothelin still under investigation. The diagnosis of MPM is based on histology using essentially immunohistochemistry on pleural biopsies best obtained by thoracoscopy. The treatment of MPM relies mostly on chemotherapy. Surgery, pleurectomy/decortication or extrapleural pneumonectomy, is not recommended outside a clinical trial, as well as adjuvant chest radiotherapy. Prophylactic irradiation of chest scars and drains, validated by the French guidelines in 2005, is however highly discussed at the international level. Finally, numerous research studies presently assess the value of targeted therapies and biomarkers in MPM, opening new perspectives in the management of this cancer.

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

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

Combined chemotherapy with cytotoxic and targeted compounds for the management of human malignant pleural mesothelioma

Human malignant pleural mesothelioma (hMPM) is an aggressive asbestos-associated cancer, the incidence of which is increasing and which, despite progress in diagnosis and therapy, continues to have a poor prognosis. Asbestos fibers induce aberrant cell signaling, leading to proto-oncogene activation and chemoresistance. In this review, we discuss the evolution of pharmacological management of hMPM up to the most recent advances. Monotherapy with single cytotoxic drugs achieves modest objective response rates, seldom reaching 30%. However, combination regimens using novel drugs and standard molecules are showing gradually improving responses and clinical benefits. Phase II/III studies have identified pemetrexed, a multitarget folate pathway inhibitor in combination with platinum derivatives, and the cisplatin/gemcitabine association as front-line chemotherapy for hMPM. Detailed knowledge of molecular mechanisms of signal transduction and neoangiogenesis in hMPM should aid in the design and screening of other promising compounds such as more efficacious receptor tyrosine kinase inhibitors.

Cytoreductive surgery plus hyperthermic intraperitoneal chemotherapy improves survival of gastric cancer with peritoneal carcinomatosis: evidence from an experimental study

Background

Cytoreductive surgery (CRS) plus hyperthermic intraperitoneal chemotherapy (HIPEC) has been considered as a promising treatment modality for gastric cancer with peritoneal carcinomatosis (PC). However, there have also been many debates regarding the efficacy and safety of this new approach. Results from experimental animal model study could help provide reliable information. This study was to investigate the safety and efficacy of CRS + HIPEC to treat gastric cancer with PC in a rabbit model.

Methods

VX2 tumor cells were injected into the gastric submucosa of 42 male New Zealand rabbits using a laparotomic implantation technique, to construct rabbit model of gastric cancer with PC. The rabbits were randomized into control group (n = 14), CRS alone group (n = 14) and CRS + HIPEC group (n = 14). The control group was observed for natural course of disease progression. Treatments were started on day 9 after tumor cells inoculation, including maximal removal of tumor nodules in CRS alone group, and maximal CRS plus heperthermic intraperitoneal chemoperfusion with docetaxel (10 mg/rabbit) and carboplatin (40 mg/rabbit) at 42.0 ± 0.5°C for 30 min in CRS + HIPEC group. The primary endpoint was overall survival (OS). The secondary endpoints were body weight, biochemistry, major organ functions and serious adverse events (SAE).

Results

Rabbit model of gastric cancer with PC was successfully established in all animals. The clinicopathological features of the model were similar to human gastric PC. The median OS was 24.0 d (95% confidence interval 21.8 - 26.2 d ) in the control group, 25.0 d (95% CI 21.3 - 28.7 d ) in CRS group, and 40.0 d (95% CI 34.6 - 45.4 d ) in CRS + HIPEC group (P = 0.00, log rank test). Compared with CRS only or control group, CRS + HIPEC could extend the OS by at least 15 d (60%). At the baseline, on the day of surgery and on day 8 after surgery, the peripheral blood cells counts, liver and kidney functions, and biochemistry parameters were all comparable. SAE occurred in 0 animal in control group, 2 animals in CRS alone group including 1 animal death due to anesthesia overdose and another death due to postoperative hemorrhage, and 3 animals in CRS + HIPEC group including 1 animal death due to anesthesia overdose, and 2 animal deaths due to diarrhea 23 and 27 d after operation.

Conclusions

In this rabbit model of gastric cancer with PC, CRS alone could not bring benefit while CRS + HIPEC with docetaxel and carboplatin could significantly prolong the survival with acceptable safety.

Chemotherapy for malignant pleural mesothelioma

OPINION STATEMENT

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

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

OBJECTIVE

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

PATIENTS AND METHODS

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

RESULTS

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

CONCLUSION

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

Chemotherapy and radiotherapy for mesothelioma

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

Cytoreductive surgery plus hyperthermic intraperitoneal chemotherapy to treat gastric cancer with ascites and/or peritoneal carcinomatosis: Results from a Chinese center

BACKGROUND

This work was to evaluate cytoreductive surgery (CRS) plus hyperthermic intraperitoneal chemotherapy (HIPEC) for advanced gastric cancer (GC).

METHODS

CRS and HIPEC were performed on 28 GC patients with peritoneal carcinomatosis (PC) and/or malignant ascites, with survival and perioperative safety as study endpoints.

RESULTS

A total of 30 CRS and HIPEC procedures were performed. Cytoreduction scores ratings (CCR) were CCR-0 in 11 (39.2%), CCR-1 in 6 (21.4%), CCR-2 in 8 (28.8%), and CCR-3 in 3 (10.6%) cases. The 6-, 12-, 18-, and 24-month survival rates were 75%, 50%, 43%, and 43%, respectively. The median survivals of patients with PCI <or=20 and high PCI >20 were 27.7 months (95% CI 15.2-40.3 months) and 6.4 months (95% CI 3.8-8.9 months) (P = 0.000). The estimated median survival for patients with CCR-0, CCR-1, and CCR-2 and 3 were 43.4 months (95% CI, 26.9-59.9 months), 9.5 months (95% CI 6.4-12.6 months), and 7.5 months (95% CI 3.0-13.6 months) (P = 0.001, CCR0 vs. CCR1-3). No perioperative death but 1 (3.6%) serious adverse event occurred.

CONCLUSIONS

CRS plus HIPEC could offer survival advantage for selected GC patients with PC and/or ascites, with acceptable safety profile.

Carboplatin plus pemetrexed as first-line treatment of patients with malignant pleural mesothelioma: a phase II study

INTRODUCTION

Malignant pleural mesothelioma (MPM) is a rapidly progressive tumor that is increasing in frequency worldwide. Treatment options are limited, and response to chemotherapy is poor. The aim of this phase II study was to evaluate the activity of the carboplatin/pemetrexed combination as first-line chemotherapy in patients with unresectable MPM.

PATIENTS AND METHODS

Chemotherapy-naive patients with histologically confirmed MPM and an Eastern Cooperative Oncology Group performance status of 0-2 were enrolled. Treatment consisted of pemetrexed 500 mg/m2 and carboplatin area under the concentration-time curve of 5 mg/mL/min, both administered on day 1 of a 21-day cycle. The treatment continued until 6 cycles were completed or until unacceptable toxicity or disease progression were observed.

RESULTS

A total of 62 patients were enrolled. Of these patients, 18 (29%) had a confirmed partial response, whereas the disease remained stable in 34 patients (54.9%) and progressed in 10 patients (16.1%). The median overall survival (OS) was estimated at 14 months (95% CI, 11.8-16.2 months), and the median time to progression was 7 months (95% CI, 5.8-8.2 months). The difference in median OS between the epithelial histologic subtype (16 months) and the sarcomatoid subtype (11 months) was statistically significant.

CONCLUSION

This study confirmed the activity of the carboplatin/ pemetrexed combination in the first-line treatment of patients with MPM. It is a viable option, especially in cases in which side effects are generally anticipated.

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.

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

Background

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

Methods

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

Results

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

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

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

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

Conclusion

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

Cytoreductive surgery plus hyperthermic intraperitoneal chemotherapy improves survival in selected patients with peritoneal carcinomatosis from abdominal and pelvic malignancies: results of 21 cases

We evaluated the perioperative safety profile and efficacy of cytoreductive surgery (CRS) plus hyperthermic intraperitoneal chemotherapy (HIPEC) in 21 patients with peritoneal carcinomatosis (PC) from gastrointestinal and gynecological cancers. Twenty-one patients with PC (12 gastric cancer, 5 colorectal cancer, 2 ovarian cancer, 1 pseudomyxoma peritonei, 1 malignant mesothelioma) were treated with CRS + HIPEC with hydroxycamptothecin 20 mg and mitomycin C 30 mg in 12,000 mL of normal saline at 43 +/- .5 degrees C for 60 to 90 minutes. Vital signs were recorded for 5 days after surgery. We analyzed the following: local and systemic infections; gastrointestinal function recovery; hematological, hepatic, and renal parameters; wound healing time; adverse events; survival; and quality of life. The PC index was 2 to 33 (median, 11), the duration of operation 4 to 10 h (median, 8 h), and the highest temperature during 5 postoperative days 38.1 degrees C. Two patients developed generalized edema and were successfully treated. Five patients developed hypoproteinemia on day 1 after surgery. All routine blood tests checked at 1 week after surgery were normal. Time of gastric tube removal was 2 to 7 days. Liquid food intake time was 3 to 8 days. Time of removal of stitches was 8 to 18 days. No local or systemic infections, wound disruption, or other clinically important adverse events occurred. The follow-up was 8 to 43 months (median, 22.5 months). Eleven patients died, three survived with tumor, and seven survived free of tumor. CRS + HIPEC was well tolerated in our selected patients with PC, some of whom had improved survival.

Cytoreductive surgery and intraperitoneal chemotherapy for peritoneal mesothelioma

AIMS

Peritoneal mesothelioma is a rare disease and traditionally has been associated with a gloomy prognosis. The present study aimed to report the outcomes following surgery and intraperitoneal chemotherapy in selected patients with peritoneal mesothelioma.

METHODS

Clinicopathological features, operative procedures, early outcomes and survival were analysed for 17 consecutive patients who underwent surgery for peritoneal mesothelioma between 1998 and 2007. Seventeen consecutive patients who underwent surgery for peritoneal mesothelioma between 1998 and 2007 were analysed for clinicopathological features, operative procedures, early outcomes and survival.

RESULTS

Seventeen patients underwent 18 laparotomies. Most presented with abdominal distension (71%) and abdominal pain or discomfort (53%). Complete cytoreduction was achieved in 8 patients, major debulking in 8, and 1 patient had an exploratory laparotomy only due to extensive disease. One patient died on day 30 postoperatively due to a chest infection and pulmonary embolism. The median survival for 8 patients who underwent complete cytoreduction was 3.7 years (range, 0.7-6.9), whereas that for 8 patients with palliative debulking was 1.0 years year (range, 0.3-5.7). Among the 12 patients who had significant ascites as a presenting symptom, 10 reported good palliation of ascites.

CONCLUSIONS

Cytoreductive surgery combined with intraperitoneal chemotherapy appears to be the optimal treatment for selected patients with peritoneal mesothelioma. Increased familiarity with this condition's presentation and natural history, and knowledge of available treatment options, will hopefully facilitate treatment of these patients and expedite speedy referral to appropriate treatment centres.

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

PURPOSE

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

PATIENTS AND METHODS

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

RESULTS

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

CONCLUSION

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

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

BACKGROUND

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

METHODS

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

RESULTS

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

CONCLUSIONS

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

Phase II trial of pemetrexed and gemcitabine in chemotherapy-naive malignant pleural mesothelioma

PURPOSE

Pemetrexed and gemcitabine have single-agent activity in malignant pleural mesothelioma (MPM). The combination of pemetrexed/gemcitabine has not previously been studied in MPM to our knowledge.

PATIENTS AND METHODS

Patients with histologic or cytologic diagnosis of MPM were included. Cohort 1 received gemcitabine 1,250 mg/m(2) on days 1 and 8, with pemetrexed 500 mg/m(2) on day 8, and cohort 2 received gemcitabine 1,250 mg/m(2) on days 1 and 8, with pemetrexed 500 mg/m(2) on day 1. Cycles were repeated every 21 days; all patients were supplemented with folic acid and vitamin B(12) and received dexamethasone.

RESULTS

One hundred eight patients (cohort 1, n = 56; cohort 2, n = 52) with pleural mesothelioma were enrolled. Among assessable patients, response rate was 26.0% in cohort 1 and 17.1% in cohort 2. Median time to disease progression was 4.34 months for cohort 1 and 7.43 months for cohort 2. Median survival was 8.08 months for cohort 1 (1-year survival = 31.14%) and 10.12 months for cohort 2 (1-year survival = 45.80%). In cohorts 1 and 2, incidence of grade 4 neutropenia was 25.0% and 29.4%, grade 4 thrombocytopenia was 14.3% and 3.9%, grade 3 or 4 anemia was 5.4% and 5.9%, and grade 3 or 4 fatigue was 23.2% and 15.7%, respectively.

CONCLUSION

The combination of pemetrexed and gemcitabine resulted in moderate clinical activity in MPM. However, the median survival times are similar to those with single-agent pemetrexed and inferior to outcomes observed with cisplatin in combination with an antifolate.

Multidisciplinary treatment of malignant pleural mesothelioma

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

Management options for malignant pleural mesothelioma: clinical and cost considerations

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

Oxaliplatin for the treatment of cisplatin-resistant cancer: A systematic review

Oxaliplatin is widely regarded as being active in cisplatin-resistant cancer. We undertook a systematic review of the literature to identify, describe and critique the clinical and pre-clinical evidence for the use of oxaliplatin in patients with "cisplatin-resistant" cancer. We identified 25 pre-clinical cell models of platinum resistance and 24 clinical trials reporting oxaliplatin based salvage therapy for cisplatin-resistant cancer. The pre-clinical data suggests that there is cross-resistance between cisplatin and oxaliplatin in low-level resistance models. In models with high level resistance (>10-fold) there is less cross-resistance between cisplatin and oxaliplatin, which may be a reason why oxaliplatin is thought to be active in cisplatin-resistant cancer. In clinical trials where oxaliplatin has been used as part of salvage therapy for patients who have failed cisplatin or carboplatin combination chemotherapy, there was a much lower response rate in patients with platinum-refractory or resistant cancers compared to platinum-sensitive cancers. This suggests that there may be cross-resistance between cisplatin and oxaliplatin in the clinic. Oxaliplatin as a single agent had a poor response rate in cisplatin refractory and resistant cancer. Oxaliplatin performed better in combination with other agents for the treatment of platinum-resistant/refractory cancer suggesting that the benefit of oxaliplatin may lie in its more favourable toxicity and ability to be combined with other drugs rather than an underlying activity in cisplatin resistance. Oxaliplatin therefore should not be considered broadly active in cisplatin-resistant cancer.

Emerging drugs for mesothelioma

Malignant mesothelioma is an aggressive, but relatively rare, malignancy, affecting the pleura and peritoneum. The prognosis for malignant pleural mesothelioma (MPM) is poor, with median survival in the range of 8-14 months, depending on stage and presentation of disease. Long-term results of available treatments are disappointing not only in terms of prognosis, but also of local control of the disease. Therefore, relief of symptoms and improvement of quality of life parameters are the short-term goals of therapy. In advanced disease not amenable to any local approach, such as surgery, combination chemotherapy represents the current standard of care. At present, the regimen of cisplatin/pemetrexed is the medical treatment of choice. This review summarizes standard chemotherapy options and focuses on the molecular basis of the newest biologically targeted therapies to be implemented in the near future, in the management of MPM.

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

INTRODUCTION

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

METHODS

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

RESULTS

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

CONCLUSIONS

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

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.

Molecular profiling of malignant peritoneal mesothelioma identifies the ubiquitin–proteasome pathway as a therapeutic target in poor prognosis tumors

Malignant mesothelioma is an aggressive neoplastic proliferation derived from cells lining serosal membranes. The biological and clinical characteristics of epithelial type malignant mesothelioma are distinct from those of biphasic and sarcomatous type tumors. The goal of our study was to examine the molecular basis for this distinction. Microarray analysis confirmed that the molecular signatures of epithelial and biphasic histologic subtypes were distinct. Among the differentially expressed functional gene categories was the ubiquitin-proteasome pathway, which was upregulated in biphasic tumors. Cytotoxicity experiments indicated that 211H cells derived from biphasic tumors were synergistically sensitive to sequential combination regimens containing the proteasome inhibitor bortezomib and oxaliplatin. The mechanism of this synergistic response, which was not detected in cells of epithelial tumor origin, was apoptosis. Together, our results identify the ubiquitin-proteasome pathway as a biomarker of poor prognosis biphasic peritoneal mesothelioma tumors and suggest that proteasome inhibitors could increase the effectiveness of cytotoxic chemotherapy in this subset of patients.

Divided dose of cisplatin combined with gemcitabine in malignant mesothelioma

Malignant mesothelioma is a rare but notoriously chemoresistant tumor. An impressive activity of gemcitabine and cisplatin combination in malignant mesothelioma has been shown. However, the hematological toxicity and nephrotoxicity related to this regimen affect the patient's life negatively. The aim of this study is to investigate the efficacy and toxicity of divided dose of cisplatin combined with gemcitabine in chemo-naïve patients with malignant mesothelioma. Twenty-six eligible patients with malignant mesothelioma were enrolled onto the study. Cisplatin 35 mg/m(2) and gemcitabine 800 mg/m(2) were administered on days 1 and 8 as intravenous infusion in a 3-week cycle, up to maximum 6 cycles. Response and toxicity evaluations were performed in 26 patients. Male-female ratio was 11/15 with a mean age of 50.5 years (37-70). Locations of tumor were pleura in 16 patients, and peritoneum in 10 patients. All patients had epitheloid subtype of malignant mesothelioma. The partial response and stable disease were observed in 6 patients (23.1%) and in 13 patients (50%), respectively, with an overall tumor control rate of 73.1%. Seven patients (26.9%) had progressive disease. Median time to disease progression and survival were 4 and 19.5 months, respectively. Grade 3 nausea and vomiting were observed in one patient (3.8%), grade 4 neutropenia developed in one patient (3.8%) and grades 3-4 thrombocytopenia and nephrotoxicity did not develop. There was no treatment related death. Divided dose of cisplatin combined with gemcitabine, at the current dosage and schedule, appears to be an active regimen in chemotherapy-naïve patients with malignant mesothelioma, and well-tolerated.