Times Colonist

Modified polio virus used to attack brain tumours

- MARILYNN MARCHIONE

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 patients in a small study who were given geneticall­y modified polio virus, which helped their bodies attack the cancer, doctors report.

It was the first human test of this and it didn’t help most patients or improve median survival. But many who did respond seemed to have longlastin­g benefit: About 21 per cent were alive at three years versus four per cent in a comparison group of previous brain tumour patients.

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

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

Brain tumours called glioblasto­mas often recur after initial treatment. U.S. Sen. John McCain is being treated for one now. 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 immunesyst­em response it spurs to try to fight cancer. With the help of the National Cancer Institute, they geneticall­y modified poliovirus so it would not harm nerves but still infect tumour cells.

The treatment is dripped directly into the brain through a thin tube. Inside the tumour, the immune system recognizes the virus as foreign and mounts an attack.

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 was treated last August, and said a recent scan seemed to show some tumour shrinkage.

“I’m pain-free, symptom-free,” he said.

The study tested the modified poliovirus on 61 patients whose tumours 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 tumour treatments at Duke. After two years, the poliovirus group started faring better.

Follow-up is continuing, but survival is estimated at 21 per cent at two years versus 14 per cent for the comparison group. At three years, survival was still 21 per cent for the virus group versus four per cent 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, South Carolina, was the first patient treated in the study in May 2012 and it allowed her to finish college and become a nurse. Scans as recent as early June show no signs that the tumour is growing, she said.

“I believe wholeheart­edly that it was the cure for me,” she said. Her only lasting symptom has been seizures, which medicines help control. “Most people wouldn’t guess that I had brain cancer.”

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