Scientists Using Polio To Treat Brain Cancer
A new treatment shows promise in treating deadly brain cancer
There's an exciting new breakthrough in treating some types of deadly brain tumors, that uses, of all things, a polio virus. Doctors at Duke Health in North Carolina genetically altered the virus because it produces such a strong immune response in our bodies. The result is a longer life for patients whose brain cancer returned. All had glioblastoma, an aggressive and lethal type of brain cancer. Of the 61 patients in the study, 21 percent who got this new treatment had were alive three years later. While that number is low, the survival rate for glioblastoma is normally even lower, usually, a year and a half after diagnosis. The researchers compared the study group to a group of patients drawn from historical cases at Duke. Only four percent of these patients survived three years after treatment. Dr. Annick Desjardins, one of the authors, said not all patients respond, but if they do, they often become long-term survivors. Desjardins said, "The big question is, how can we make sure that everybody responds?" Stephanie Hopper was the first patient in the Duke study. She was diagnosed with glioblastoma eight years ago. She had the tumor removed, but two years later, it returned. The modified virus is directly injected into the brain during surgery. After treatment, Hopper's tumor shrunk to the point where it's barely noticeable in her brain scans, and the tumor is continuing to shrink. Dr. Darell Bigner is the senior author of the study which was published in the New England Journal of Medicine. He explained that by modifying the virus, it destroyed its ability to infect nerve cells and cause polio, but the virus retained the ability to kill cancer cells. In fact, the modified virus targeted the tumor cells. Prior to the study, the researchers decided they needed a different approach to treating glioblastomas which is why they looked at experimenting with the polio virus. One of the goals of a phase one trial is to find a dose that is safe. In some patients, the therapy caused their brains to swell and they experienced seizures and other bad side effects so the dose was lowered. Study participants were selected according to the size of their recurring tumor, its location in the brain and other factors designed for patient protection. For five of the 61 patients in the trial, the cancer returned. They were treated a second time and Bigner says, "Those that we've been able to follow long enough have responded to the treatment the second time. That's extremely important." Combining the polio virus with other approved therapies is one approach already being tested at Duke to improve survival. The researchers are continuing their work on treating glioblastomas and planning other studies as well. They want to test the therapy on children's brain tumors. The therapy may also expand beyond brain tumors to include breast cancer and melanoma patient as well.