Poliovirus engineered to help fight brain tumors

One of the world's most dreaded viruses has been turned into a treatment to fight deadly brain tumors.

Survival was better than expected for some patients in a study who were given genetically modified poliovirus, which helped their bodies attack the cancer, doctors reported. It was the first human test of the treatment and it didn't help most patients or improve median survival. But many who did respond seemed to have long-lasting benefit: About 21 percent were alive at three years versus 4 percent in a comparison group of brain tumor patients.

Similar survival trends have been seen with some other therapies that enlist the immune system against different types of cancer. None are sold yet for brain tumors.

"This is really a first step," and doctors were excited to see any survival benefit in a study testing safety, said one researcher, Duke University's Dr. Annick Desjardins.

Preliminary results were published online by the New England Journal of Medicine.

Brain tumors called glioblastomas often recur after initial treatment. Sen. John McCain is being treated for one. Immunotherapy drugs like Keytruda help fight some cancers that spread to the brain but have not worked well for ones that start there.

Polio ravaged generations until a vaccine came out in the 1950s. The virus invades the nervous system and can cause paralysis. Doctors at Duke wanted to take advantage of the strong immune system response it spurs to try to fight cancer. With the help of the National Cancer Institute, they genetically modified poliovirus so that it would not harm nerves but still infect tumor cells.

When doctors explained the idea to Michael Niewinski, it seemed a feat "like putting a man on the moon," he said. The 33-year-old from Boca Raton, Fla., was treated last August, and said a recent scan seemed to show some tumor shrinkage. "I'm pain-free, symptom-free," he said.

The study tested the modified poliovirus on 61 patients whose tumors had recurred after initial treatments. Median survival was about a year, roughly the same as for a small group of similar patients given other brain tumor treatments at Duke. After two years, the poliovirus group started faring better.

Follow-up is continuing, but survival is estimated at 21 percent at two years versus 14 percent for the comparison group. At three years, survival was still 21 percent for the virus group versus 4 percent for the others.

Eight of the 35 patients who were treated more than two years ago were alive as of March, as were five out of 22 patients treated more than three years ago.

Stephanie Hopper, 27, of Greenville, S.C., was the first patient treated in the study in May 2012 and it allowed her to finish college and become a nurse. Scans show no signs that the tumor is growing, she said. Her only lasting symptom has been seizures, which medicines help control. "Most people wouldn't guess that I had brain cancer."

One independent expert, Dr. Howard Fine, brain tumor chief at New York-Presbyterian and Weill Cornell Medicine, said it was disappointing to see no improvement on median survival, but encouraging to see "extraordinary responders, a small group of patients who have done markedly better than one would expect."

Duke has started a second study in adults, combining the poliovirus with chemotherapy, to try to improve response rates.