A genetically modified poliovirus therapy significantly improved the long-term survival rate of patients with glioblastoma in a phase 1 clinical trial. The vaccine shows promise for treating other forms of cancer as well.

The study, presented at the 22nd International Conference on Brain Tumor Research and Therapy in Norway and simultaneously published in The New England Journal of Medicine, builds upon 18 years of nonhuman primate research.

The US Food and Drug Administration required that the treatment was tested in laboratory animals first to ensure that the modified poliovirus would be safe in humans, according to "The Critical Role of Nonhuman Primates in Medical Research," a white paper produced by the Foundation for Biomedical Research.

Glioblastoma is a fast-growing, aggressive brain tumor. Without treatment, patients survive less than three months and fewer than 3-5% of people survive this type of cancer for five years, according to the 2014 World Cancer Report.

In contrast, the 61 patients that partook in this recent clinical trial had a three year survival rate of 21%.

"This therapy is potentially a game changer, not just for glioblastoma, but all cancers, although it's premature to say for sure yet," study author, Henry Friedman, MD, a neuro-oncologist at Duke University, told ALN.

The therapy infuses a genetically modified form of the poliovirus vaccine directly into the brain tumor. The modified virus, which is delivered via a surgically implanted catheter, directs a targeted immune response to tumor cells.

The Duke University-based research team initially planned to increase the dosage for this trial. However, some patients experienced seizures and cognitive disturbances caused by inflammation at higher doses.

Two-thirds (69%) of the patients reported mild or moderate adverse events attributed to the poliovirus as a side effect.

Planning for a phase 2 study that combines the poliovirus therapy with a chemotherapy drug is currently underway.

"This therapy is potentially a game changer, not just for glioblastoma, but all cancers, although it's premature to say for sure.

Clinical trials testing the polivirus therapy's effectiveness at treating pediatric brain tumors, breast cancer, and melanoma should begin soon.

"It's incomprehensible to me that there are people out there who believe it is immoral to use animals for biomedical research," Friedman, who is also a member of the Foundation for Biomedical Research advisory board, said

"Certain things can be done in the test tube or the petri dishes, but in order to really test to see if something is safe and effective in people, animal models are necessary."