Malignant pleural mesothelioma (MPM) is an aggressive cancer, primarily brought on by asbestos exposure. Recent studies by Pavel A Levin and Jonathan E Dowell at the Division of Hematology/Oncology, University of Texas Southwestern Medical Center, have revealed adding bevacizumab to the combination of cisplatin and pemetrexed gives hope to selected mesothelioma victims by potentially extending life an additional two, to two and a half months.
How does bevacizumab help?
Surgery and radiation have their roles in treatment, but both have limitations. The primary treatment for most patients is systemic chemotherapy.
It is recognized that vascular endothelial growth factor (VEGF) and its receptor are major biologic factors in this disease. Bevacizumab is a monoclonal antibody that binds VEGF and blocks its interactions with VEGF receptors. That means angiogenesis, the forming of new blood vessels leading to tumors, is blocked by bevacizumab.
At first, a single chemotherapy agent was used, but with limited effectiveness in MPM. In 2004, the combination of cisplatin and pemetrexed was approved with an almost three month increase in overall median survival. This remains the only National Comprehensive Center Network category 1 MPM recommendation – based on the patient tolerating both drugs. Now the addition of bevacizumab to the cisplatin and pemetrexed is included in the National Comprehensive Cancer Network guidelines (with a category 2A recommendation) as a feasible first-line treatment for unresectable MPM in suitably selected patients.
What is bevacizumab?
This is an anti-VEGF antibody created in 1997. It then went through multiple studies which finally led to this 2017 report. In this last study, only patients without known side effects to bevacizumab were included as not all MPM patients would benefit from this additional antibody. Since there is currently no way to identify the ideal patient, additional immunotherapy agents are also being investigated with preliminary studies showing encouraging results.
What is next?
Since anti-VEGF therapies possibly increase the effect of immunotherapy in cancer, there is a persuasive rationale for future trials targeting VEGF together with immunotherapy in MPM. A current trial of pembrolizumab and nintedanib is recruiting patients now for a variety of malignancies, including MPM. Additional clinical studies with bevacizumab-based chemotherapy in combination with immunotherapy for patients with MPM are expected.
The takeaway from this new development is that MPM patients who tolerate the chemotherapy agents may extend their lives a few months. However, the larger picture is that there are constantly new research studies and trials that will, hopefully, no longer make mesothelioma the incurable cancer it is today.
