May 15, 2014
A Megadose Of The Measles Virus Kills Woman’s Cancer In Early Trial
Brett Smith for redOrbit.com - Your Universe Online
In an early stage, proof-of-principle trial, researchers from the Mayo Clinic have demonstrated that a modified version of the measles virus is capable of destroying cancerous cells while leaving normal healthy tissue intact, according to a new report in Mayo Clinic Proceedings.
In the trial, two patients with multiple myeloma were injected with a single massive dose of a genetically-engineered measles virus – enough to inoculate 10 million people. The virus was modified to only attack myeloma plasma cells and both patients responded positively to the treatment. One patient, Stacy Erholtz, experienced a complete remission.
Myeloma is a cancer of plasma cells in bone marrow, which typically spreads throughout the body.
“It’s a landmark,” Dr. Stephen Russell, a Mayo Clinic hematologist who helped develop the virus-based treatment, told the Minneapolis Star Tribune. “We’ve known for a long time that we can give a virus intravenously and destroy metastatic cancer in mice. Nobody’s shown that you can do that in people before.”
The treatment was not without its complications. After receiving the injection, Erholtz quickly fell ill – developing an extreme headache in about five minutes. Within two hours, the 49-year-old mother was shaking and vomiting. Eventually, her temperature hit 105 degrees F.
Following this difficult ordeal, the multiple tumors on Erholtz’s body began to shrink and eventually disappear.
While the second patient in the trial did not respond as well to the experimental treatment, her imaging studies presented a distinct proof that the intravenously-given virus expressly targeted the locations of tumor growth. Advanced imaging analyses were possible only because the virus had been designed with an easily discernible marker that scientists could use to figure out its location in the body.
Scientists have known for years that certain viruses can be designed to eliminate cancer. They attach to tumors and make use of them as hosts to reproduce their very own genetic code. Cancer cells gradually rupture during this process and release the virus. Antiviral vaccines have been made safe and can also be customized to carry radioactive molecules to help wipe out cancer cells without triggering extensive damage to healthy cells surrounding the tumors. The body’s immune system then assaults any leftover cancer that has traces of the vaccine.
Russell said future studies need to determine why the second patient in the study did not respond to the viral treatment as well as Erholtz. Unfortunately, that patient cannot be given a second dose of the measles-based therapy since the treatment only works on individuals who have never been exposed to the virus before. People who have been exposed to measles have antibodies against the virus in their bloodstream – neutralizing the anti-cancer virus once it enters the body.
Russell speculated that researchers may eventually be able to develop a sort of Trojan horse for the anti-cancer virus using the patient’s own cells.
“That way it doesn’t get destroyed before it reaches its target,” he said.
Despite her initial ordeal, Erholtz told the Tribune she has no regrets about participating in the study and hopes to be cancer-free at her next check-up.
“We don’t let the cancer cloud hang over our house, let’s put it that way, or we would have lived in the dark the last 10 years,” she said.