Polio virus may help fight brain cancer

An unexpected ally, the polio virus, one of the world’s most dreaded viruses, may be the answer for fighting deadly brain tumors.  A small study of 61 patients with brain cancer at Duke University in Durham, N.C., found that 21 percent of patients who got the new treatment were still alive three years later, compared to only 4 percent of those who received standard therapy.

Researchers with the study were able use a harmless form of the polio virus that was genetically modified, that helped the patient’s bodies attack the cancer, significantly boosting their chances of survival.  The genetically modified polio virus was developed at the Duke Cancer Institute. Patients who participated in the study were those who had recurrent glioblastomas.  Brain tumors called glioblastomas have a tendency to recur after initial treatment.  This is the same type of tumor Arizona Senator John McCain is being treated for. 

This study was the first human test using the polio virus.  This new approach uses an altered, harmless form of the polio virus to target and destroy glioblastoma cells while triggering a powerful immune response. 

Findings from this study have been published in the New England Journal of Medicine and have been presented at the International Conference on Brain Tumor Research and Therapy, in Norway.

Even though these results are exciting and show much promise for future use, more data is still needed.  Larger randomized studies are necessary to perform to definitively determine whether this treatment will be effective in brain tumor patients.

Polio, also known as poliomyelitis, is a crippling and potentially deadly infectious disease caused by the poliovirus.  The virus spreads from person to person and ran rampant for generations until a vaccine came out in the 1950s.  The virus invades the nervous system and can cause paralysis.  The researchers at Duke wanted to take advantage of the strong immune system response it causes to try to fight cancer.  With the help of the National Cancer Institute, they were able to genetically modify the poliovirus so it would not attack and harm nerves but still would infect tumor cells.

The findings from this study are the first major hope in treating recurrent glioblastoma.  To administer the treatment, the virus is dripped directly into the brain through a thin tube.  Once inside the tumor, the immune system views the virus as a foreign substance and sets out to attack and destroy it. 

Up to two-thirds of the patients in the study who received the poliovirus had side effects which included brain inflammation, headaches, muscle weakness, seizures, trouble swallowing, and altered thinking skills. These symptoms were due to the immune response in the brain and not as a result of the treatment.

At this time, Duke has begun a second study in adults, combing poliovirus with chemotherapy to see if they get improved response rates.  There is also a study in children with brain tumors that is underway and studies for breast cancer and skin cancer planned too.