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Cancer-Killing Virus Shows Success In Brain Cancer Patients

Joanna Lawrence
5th June, 2016

Not all viruses are bad. There has been a lot of recent research into creating synthetic viruses to target cancer cells. Until now however, a breakthrough has been lacking. In a clinical trial involving patients with brain cancer, viruses carrying a special drug within their molecular body were administered to the patients. It was found that the virus would seek out the cancer cells and neutralize them with the drug they were carrying. All of the 45 patients were suffering from an aggressive form of brain cancer. It was found that when the drug-carrying friendly virus was administered, survival rates doubled. According to the researchers, brain cancer is a highly aggressive form of cancer with few treatment options available. Nevertheless, the new viral therapy may just change that entirely. This isn’t the first time that a cancer-neutralizing virus has been created in the laboratory. However, prior synthetic viruses worked by targeting all cancer cells directly. The new virus named “Toca 511” selectively targets cancer cells with a weakened defense system that would otherwise make it difficult if not impossible for the virus to infect. Prior viruses had a low rate of success since cancer cells often successfully fought them due to their highly active defense. By bypassing these “strong” cancer cells entirely, the virus works by slowing destroying the cancer from the weakest link. Once the virus is inside the cancer cell, it imprints a genetic blueprint for a killer-enzyme into the cells’ DNA. As the cancer cell then reads through its genome, it produces the enzyme, which is actually a form of yeast that acts as a cancer-cell killer from within. Enrolled patients included those with some of the deadliest forms of brain cancer in the population – known as high grade gliomas. Prior studies showed that patients typically lived for just over 7 months after the first or second incident of brain cancer re-occurrence. Similar patients in the current study who also had re-occurring brain cancer had a mean survival span of 13.6 months, nearly double the lifespan compared to patients not receiving Toca 511. No major side effects were noted in the patients who were administered the virus. Also, after treatment had finished, extensive blood analysis was done on each patient and no remnants of the virus could be detected other than in the brain tumor cells. This seems to suggest that the virus does indeed selectively target only the cancer cell lines. The results may provide hope to brain cancer sufferers in the future, however currently the drug is only in a Phase I trial. Treatment needs to be administered to larger groups of patients before the results can be confirmed. Phase Ii trials are expected to begin shortly. Study Source: Science Daily, 2016