The Grapevine

Brain Cancer Treatment: Poliovirus Therapy May Help Patients Live Longer

Patients diagnosed with a recurrent brain cancer saw improved long-term survival rates after being treated with poliovirus therapy. This was the result of a phase 1 study led by Duke University School of Medicine in Durham, North Carolina.

The study titled "Recurrent Glioblastoma Treated with Recombinant Poliovirus" was published in the New England Journal of Medicine on June 26.

The team from Duke recruited 61 patients who experienced the return of their Glioblastoma (a deadly form of cancer occurring in the brain or spinal cord) after treatment. 

"Glioblastoma remains a lethal and devastating disease, despite advances in surgical and radiation therapies, as well as new chemotherapy and targeted agents," said neurologist Dr. Darell Bigner, who led the research. "There is a tremendous need for fundamentally different approaches."

Past research estimated the average survival duration to be somewhere in the range of 12 to 18 months after maximal treatment. There were very few documented cases of long-term survival.

But in the new study, researchers tested a genetically modified version of the polio vaccine (developed at Duke Cancer Institute) and found some patients were able to live a lot longer than they would have. Three years after the treatment, 21 percent of the patients were still alive compared to a control group where only 4 percent were still alive.

"It’s very unusual, almost unprecedented to get this kind of long-term survival," explained Bigner.

The results were of significance since all the patients had a "dismal" diagnosis and were expected to survive for less than two years.

He also explained how the poliovirus used in different doses was weakened and genetically engineered to carry parts of a rhinovirus. 

"We inject the virus directly into brain tumors and it kills all the tumor cells it comes in contact with," he said. "The most important thing is, it sets up a secondary immune response and really destroys the distant tumor cells."

A majority of the patients (46 out of the total 61) were provided with low doses because of adverse reactions observed in the few patients who received higher doses. These reactions included too much inflammation, seizures, cognitive disturbances and more. 

"Similar to many immunotherapies, it appears that some patients don’t respond for one reason or another, but if they respond, they often become long-term survivors,” said co-lead author Dr. Annick Desjardins. "The big question is, how can we make sure that everybody responds?"

The phase 1 clinical trial results of the poliovirus therapy were presented at the 22nd International Conference on Brain Tumor Research and Therapy in Norway on June 26. Currently, a phase 2 study is underway in which the researchers are testing a combination of the poliovirus therapy and the chemotherapy drug lomustine.