Malignant Pleural Mesothelioma: State-of-the-Art on Current Therapies and Promises for the Future

Abstract

Malignant pleural mesothelioma (MPM) is a rare, aggressive cancer of the pleural surface associated with asbestos exposure. The median survival of MPM patients is a mere 8-14 months, and there are few biomarkers and no cure available. It is hoped that, eventually, the incidence of MPM will drop and remain low and constant, given that most nations have banned the use of asbestos, but in the meantime, the incidence in Europe is still growing. The exact molecular mechanisms that explain the carcinogenicity of asbestos are not known. Standard therapeutic strategies for MPM include surgery, often coupled with chemotherapy and/or radiotherapy, in a small percentage of eligible patients and chemotherapy in tumors considered unresectable with or without adjuvant radiotherapy. In recent years, several new therapeutic avenues are being explored. These include angiogenesis inhibitors, synthetic lethal treatment, miRNA replacement, oncoviral therapies, and the fast-growing field of immunotherapy alone or in combination with chemotherapy. Of particular promise are the multiple options offered by immunotherapy: immune checkpoint inhibitors, tumor vaccines, and therapies taking advantage of tumor-specific antigens, such as specific therapeutic antibodies or advanced cell-based therapies exemplified by the CAR-T cells. This review comprehensively presents both old and new therapeutic options in MPM, focusing on the results of the numerous recent and on-going clinical trials in the field, including the latest data presented at international meetings (AACR, ASCO, and ESMO) this year, and concludes that more work has to be done in the framework of tailored therapies to identify reliable targets and novel biomarkers to impact MPM management.

Keywords: CAR (chimeric antigen receptor) T cells; immunotherapy; malignant pleural mesothelioma (MPM); mesothelin; miRNA replacement.

Figure 1

Current and innovative clinical approaches for MPM. Different segments represent MPM standard therapies (light brown), MPM non-specific target-based therapies (brown), and MPM surface antigen-dependent therapies (orange). inh., inhibitor; DCV, dendritic cell vaccination; WT1, Wilms' Tumor Antigen; CAR, chimeric antigen receptor; IL-2, interleukin-2; TILs, tumor-infiltrating lymphocytes; MSLN, mesothelin; FAP, fibroblast activation protein; CAFs, cancer-associated fibroblasts; PE, Pseudomonas exotoxin A.