A new mesothelioma clinical trial being conducted at the Mayo Clinic uses an altered version of the measles virus to combat the deadly cancer.
The potential of the measles virus to kill cancers like mesothelioma was noticed many years ago, before vaccination curtailed the spread of measles. In several cases, cancer patients who contracted natural measles experienced shrinkage of their tumors. Today, advanced molecular science has made it possible to insert a new gene into the measles virus that can further increase its specificity and potency against mesothelioma tumor cells.
Because malignant pleural mesothelioma (the most common type) arises on the mesothelial membrane around the lungs, Mayo Clinic researchers administer the altered measles virus directly into the pleural space, between the lungs and the membrane. The virus is delivered via catheter and includes a type of radioactive iodine, making it possible to monitor its effect on a mesothelioma tumor using non-invasive imaging studies.
The experimental treatment, which is classified as virotherapy, has worked well in both the laboratory and in live mice. In fact, some mice with mesothelioma that were injected with the measles virus lived twice as long as those who were not injected. The new Phase I clinical trial at Mayo, which is supported by the National Cancer Institute, represents the first time the treatment will be used in human mesothelioma patients.
Once it enters the pleural space and comes in contact with mesothelioma cells, the hope is that the measles virus will not only begin killing the cells themselves, but will also trigger an anti-tumor immune response that will further increase the assault on the mesothelioma tumor. The Phase I trial participants must have mesothelioma confined to a single pleural cavity. They will receive a dose of measles virus every 28 days up to six times, or until the side effects are not tolerable. The primary purpose of the trial is to evaluate the safety of measles virotherapy and determine the optimal dose.
Virotherapy is also a focus of cancer research at the Salk Institute for Biological Studies where researchers are studying the mesothelioma-killing potential of the adenovirus, which causes the common cold. Salk researchers say the adenovirus has developed molecular proteins that allow it to “hijack” a cell’s internal machinery and control it. Scientists are working to incorporate these same tools into anti-cancer drugs that might be able to suppress cells’ ability to grow, replicate and spread.
Cold viruses point the way to new cancer therapies, October 16, 2012, News Release, Salk Institute website.