The Mayo Clinic is currently conducting a clinical trial to determine whether an altered version of the measles virus will be effective in combating mesothelioma, a deadly cancer that affects up to 3,000 Americans every year.
Many years ago, even before the measles vaccination came into use, doctors and scientists noticed the potential the virus had to kill cancers like mesothelioma. This possibility was brought to light when several cancer patients who were diagnosed with measles showed tumor shrinkage. Now, researchers can use advanced molecular science to insert a new gene into the measles virus that can enhance its ability to fight tumor cells in mesothelioma patients.
The most common type of mesothelioma, pleural mesothelioma, affects the mesothelial membrane around the lungs. During this clinical trial, Mayo Clinic researchers are administering the altered measles virus between the lungs and the membrane, directly into the pleural space affected by the disease. When the virus is delivered via a catheter, it is treated with a type of radioactive iodine so that researchers can use non-invasive imaging technology to monitor its effects on the cancer cells.
Researchers have dubbed this experimental treatment “virotherpay”. It has been successful in the laboratory and in live mice: some mice that had mesothelioma and were injected with the virus lived up to twice as long as mice who did not receive the experimental treatment. The National Cancer Institute is supporting the new Phase I clinical trial at Mayo, and this is the first time this experimental treatment will be applied to human subjects.
Researchers hope that the virus won’t only kill the cancer cells it comes into contact with, but that it will also trigger an autoimmune response that will cause further damage to tumors. Participants in the trial must be diagnosed with mesothelioma confined to a single pleural cavity. The patients who participate in the trial will be given a dose of the virus every 28 days over the course of six months, or until side effects become intolerable, helping doctors to determine the safety of the therapy and proper dosing.
The Salk Institute for Biological Studies is also conducting research with virotherapy by studying the effect of the adenovirus (which causes the common cold) on mesothelioma cells. These researchers say that molecular proteins developed by the virus can “hijack” the internal machinery of a cell, seizing control of that cell. The hope is that this will eventually evolve into a treatment that suppresses cancer cells’ ability to grow, replicate, and spread.