In 2012, researchers at the Mayo Clinic and the University of Minnesota partnered “to harness a unique therapeutic approach” for mesothelioma. Concerned with the increasing number of diagnoses of mesothelioma in Minnesota, the researchers set up a clinical trial aimed at determining the effectiveness of treating mesothelioma with an engineered version of the measles virus. Now, nearly five years later, the trial is recruiting patients.
Although mesothelioma is only known to occur as a result of exposure to asbestos, a disproportionate number of mesothelioma cases were diagnosed among miners, and their families, in the Minnesota Iron Range taconite mine. In the final report issued in Nov. 2014 of a study that was undertaken after 52 miners were found to have contracted the asbestos-caused cancer, the death toll had climbed to 101. Pleural mesothelioma is one of the most aggressive and deadliest forms of cancer, with limited treatment options. While chemotherapy and radiation are most often used to relieve symptoms, the cancer often metastasizes leaving the patients with a very short survival time.
“We’ve taken a new viral agent, repositioned it for this disease and are advancing it toward the clinic as an entirely novel treatment,” said Stephen Russell, M.D., Ph.D., Mayo Clinic molecular researcher who conceived the idea of using the measles virus vector against mesothelioma in 2012 when the trial was initially established. Russell outlined the research in Mayo’s online magazine, Discovery’s Edge.
According to the World Health Organization, measles is one of the leading causes of death in young children, but when vaccinations, derived from the MV strain Edmonston B (MV-Edm) were used, there was a 79 percent drop in deaths from the disease. Armed with this statistic, and with the fact that MV-Edm has shown to be effective against other cancers, the team of Minnesota researchers worked to transform the MV-Edm in hopes that it will also kill off mesothelioma cells.
In initial results reported in Oncotarget last month, the researchers treated four mesothelioma cell lines with MV-Edm. The team found that “cell viability is diminished substantially compared to untreated cells, and in three of four MM [malignant mesothelioma] cell lines cell viability is decreased extensively, compared to non-transformed mesothelial cells.”
The success of the study, according to the researchers, is partially related to the CD46 protein that “is the primary receptor for Edmonston vaccine strains of measles virus.” Studies have shown overexpression of CD46 by a majority of malignant pleural mesothelioma cell lines compared to healthy cells. CD46 is a protein found in measles, and can act as a receptor for the Edmonston strain of measles virus, according to Gene Cards.
With a goal of enrolling 36 patients, the trial is currently recruiting malignant pleural mesothelioma patients. The patients will receive the measles virus dose, injected into their chest cavities through catheters that also serve to drain excess fluid caused by the disease from around their lungs. After completion of treatment, patients will be followed up every three to six months for up to five years.
Currently, there is no known cure for mesothelioma.If this novel treatment proves as successful on humans as in the lab, it could be the breakthrough all mesothelioma sufferers and their physicians have been awaiting. Estimated completion date for the trial is January 2019.
The researchers received a grant from the Mesothelioma Applied Research Foundation in 2011 toward the trial.
For more information on this promising study see the June 27 issue of OncoTarget.