Mesothelioma patients and their families are cautiously optimistic about a new vaccine that may help fight the illness by harnessing the power of the patients’ own immune system.
Mesothelioma is caused by exposure to asbestos – a type of mineral fiber. These fibers can cause cellular changes that eventually turn cells cancerous.
The new vaccine, which was tested in Holland and described in a recent issue of The American Journal of Respiratory and Critical Care Medicine, is a form of immunotherapy, a new approach to combating cancer. In essence, researchers claim to have found a way to ‘teach’ certain immune system cells, known as dendritic cells, to recognize malignant mesothelioma cells as ‘enemies’ and launch an attack. In the study, information from the mesothelioma cells – called an antigen – was inserted into the dendritic cells. The result was an immune response against the tumors.
In this study, ten patients with malignant pleural mesothelioma received three of the experimental vaccinations at two-week intervals after chemotherapy. There were no severe, life threatening or disabling side-effects (i.e. grade 3 or 4 toxicities) associated with the vaccines or any evidence of autoimmunity. Most importantly, there was evidence of cell killing activity against tumor cells in a subgroup of patients.
While it is a hopeful development, the vaccine is still a long way from being a magic bullet against this rare but deadly cancer. Mesothelioma cells can cause suppression of the immune system and researchers must find a way to counter that in order for the new immunotherapy to be as effective as possible.
In addition, although the therapy appears to be safe and there was evidence that it killed mesothelioma cells, there is still no evidence that it can increase life span. Many mesothelioma patients, like actor and NFL star Merlin Olsen who recently died of the disease, die within a year of diagnosis.
Although immunotherapy using dendritic cells has been tried in mice, this study represents the first time such a treatment has been tried in mesothelioma patients. The study’s authors say they are hopeful that with further research and development, the vaccine may serve as protection for people who have been exposed to asbestos, as well as improve and extend the lives of those who have mesothelioma.
Because of the long latency of mesothelioma, this research could have implications for thousands of people who were exposed to asbestos in the last 20 to 40 years. Approximately 2,000 people are diagnosed with mesothelioma annually and that number is not expected to decline until at least 2020.
Joost P Hegmans, et al., Consolidative Dendritic Cell-Based Immunotherapy Elicits Cytotoxicity Against Malignant Mesothelioma. American Journal of Respiratory and Critical Care Medicine, 2010
Predt, Robert. “Vaccine for Asbestos-Related Cancer Looks Safe”, March 4, 2010. HealthDay, MSN.