The enemy becomes an ally: the poliovirus is used to fight brain tumors

One of the most dreaded viruses in the world has been turned into a treatment for fighting deadly brain tumors. Survival was better than expected for patients in a small study who received genetically modified polioviruses, which helped their bodies attack cancer, doctors report.

This was the first human test of this and it did not help most patients or improve median survival. But many who responded seemed to have a lasting benefit: about 21 percent were alive at age 3 versus 4 percent in a comparison group of patients with previous brain tumors.

Similar survival patterns have been observed with other therapies that enlist the immune system against different types of cancer. None is still sold for brain tumors.

"It's really a first step," and the doctors were delighted to see a survival benefit in a safety study, said a researcher, Dr. Annick Desjardins of Duke University.

Preliminary results were to be discussed Tuesday at a conference in Norway and published online by the New England Journal of Medicine.

MAKE AN ENEMY AN ALLIED

Brain tumors called glioblastomas often return after initial treatment. Senator John McCain is being treated for one now. Immunotherapy drugs like Keytruda help fight some cancers that spread to the brain, but that have not worked well for those who are born there.

Polio ravaged generations until a vaccine was published in the 1950s. The virus invades the nervous system and can cause paralysis. Duke's doctors wanted to take advantage of the strong immune system reaction that he causes to fight against cancer. With the help of the National Cancer Institute, they have genetically modified the poliovirus so that it does not harm nerves but still infects tumor cells.

The treatment is poured directly into the brain through a thin tube. Inside the tumor, the immune system recognizes the virus as alien and mounts an attack.

When the doctors explained the idea to Michael Niewinski, it seemed like a feat "like putting a man on the moon," he said. The 33-year-old man from Boca Raton, Florida, was treated last August and said that a recent review seemed to show some shrinkage of the tumor.

"I am painless, without symptoms," he said.

RESULTS OF THE STUDY

The study tested the modified poliovirus on 61 patients whose tumors had recurred after the initial treatments. The median survival was about a year, about the same as for a small group of similar patients who received other Duke brain tumor treatments. After two years, the poliovirus group started to get better out of it.

Follow-up continues, but survival is estimated at 21% at two years compared to 14% for the control group. At three years, survival was still 21% for the group of viruses against 4% for the others.

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

Stephanie Hopper, 27, of Greenville, South Carolina, was the first patient treated in the study in May 2012, which allowed her to complete her studies and become a nurse. Scans as recent as at the beginning of June show no signs of tumor growth, she said.

"I sincerely believe that it was the cure for me," she said. His only lasting symptom has been epileptic seizures, which help control. "Most people did not guess that I had brain cancer."

SIDE EFFECTS

The treatment causes a lot of brain inflammation and two thirds of the patients have side effects. The most common were headache, muscle weakness, seizure, difficulty swallowing and impaired thinking abilities. The doctors pointed out that these were due to the immune response in the brain and that no one had polio as a result of the treatment.

One patient had severe brain bleeding right after the procedure. Two patients died relatively soon after treatment – one of the worsening of the tumor and the other complications of a given drug to manage a side effect. The planned doses had to be reduced because there were too many seizures and other problems at the higher doses initially chosen.

An independent expert, Dr. Howard Fine, Chief of Brain Tumors in 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 definitely better than we could expect. "

The numbers in the study are low, but it is unusual to see many alive after several years, and suggests that the approach deserves more and more important studies, he said. said.

NEXT STEPS

The National Cancer Institute manufactured the modified virus. Federal grants and several charities funded the work. Some study leaders have formed a company that licenses patents on Duke's treatment.

Duke began a second study in adults, combining poliovirus with chemotherapy, to try to improve response rates. A study in children with brain tumors is also underway, and studies on breast cancer and melanoma of skin cancer are also planned.

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Marilynn Marchione can be followed at @MMarchioneAP.

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The Associated Press Health & Science Department receives support from the Department of Science Education at the Howard Hughes Medical Institute. The AP is solely responsible for all content.