Recent advances in the treatment of malignant pleural mesothelioma

Malignant pleural mesothelioma clinically manifests after decades of initial exposure to etiologic agents, such as asbestos, and presents with nonspecific symptoms such as dyspnea, pain, or weight loss. In patients with limited, resectable disease, surgical therapy with extrapleural pneumonectomy or pleurectomy is recommended, although, it is unclear which approach is superior. Radiation has a limited role and is used primarily for palliation. The palliative efficacy of traditional chemotherapeutic agents and combination regimens is modest at best. The combination of cisplatin and pemetrexed, a novel multitargeted antifolate agent, is the approved "standard of care" for patients with unresectable malignant pleural mesothelioma. A number of molecularly targeted agents are currently under evaluation for mesothelioma such as the Histone deacetylase (HDAC) inhibitors that have demonstrated promising anticancer activity. Vorinostat, a small molecule inhibitor of HDAC, which targets select members of class I and II HDACs, has shown early evidence of activity and is currently being evaluated in a randomized study for patients who progress with standard therapy for advanced mesothelioma. It is hoped that the HDAC inhibitors and other novel targeted agents will pave the way for improved outcomes for patients with this disease.

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.

[Malignant pleural mesothelioma: interrogations and hopes concerning the expected epidemic]

Malignant pleural mesothelioma (MPM) is a rare incurable tumor. Interest in MPM has increased in recent years due to a steadily increasing incidence subsequent to the intensive use of asbestosis, the main causal agent, but also due to better awareness in the political and scientific communities faced with a serious public health issue. Our knowledge of MPM has improved regularly in terms of pathologic diagnosis and the mechanisms underlying the mesothelial carcinogenesis. MPM is also the subject of many technological innovations as illustrated by the recent identification of new biological markers, access to metabolic imaging, and clinical research on targeted treatments. Proper management implies the participation of the general population since the implementation of administrative procedures for social indemnities. In 2007, a more aggressive therapeutic approach is becoming common practice with the use of radiotherapy and the emergence of the concept of multimodal care centered on wide pleuropneumonectomy. These advances create real hope for improvement, but also many interrogations since no standard treatment protocol has been clearly identified.