Promising glioma treatment from Treovir for kids uses genetically modified herpes virus to fight brain cancer
For decades, a deadly childhood cancer called glioma has eluded the best tools of science. Now doctors have made progress with an unusual treatment: drip millions of copies of a virus directly into children’s brains to infect their tumors and trigger an immune system attack.
A dozen children treated in this way lived more than twice as long as comparable patients in the past, doctors reported at a conference of the American Association for Cancer Research and in the New England Journal of Medicine.
While most children eventually die of their disease, some are still alive for several years after treatment – something that’s virtually unheard of with these tumors.
“This is the first step, a critical step,” said study leader Dr. Gregory Friedman, a childhood cancer specialist at the University of Alabama at Birmingham. “Our goal is to improve this.”
Dr. Gregory Friedman, a pediatric cancer specialist in Birmingham, Alabama, is leading a study to treat a deadly childhood cancer with a treatment that involves injecting the herpes virus directly into the brain to stimulate an immune system response to the cancer cells . Denise McGill / Children’s of Alabama Hospital
Friedman said this could be by trying it when patients are first diagnosed or by combining it with other therapies to boost the immune system.
The children in the study were given the experimental approach after other treatments failed.
The study involved gliomas, which make up 8% to 10% of brain tumors in children. Usually treated with surgery, chemotherapy, or radiation, they often come back. And when they do, the survival averages are under six months.
In such cases, the immune system has lost the ability to recognize and attack the cancer.
So scientists have been looking for ways to turn the tumor into a new target. They turned to the herpes virus, which causes cold sores and stimulates a strong immune system response. Treovir, a company in the suburbs of Philadelphia, developed a treatment by genetically modifying the virus so that it would infect cancer cells only.
By means of small tubes inserted into the tumors, doctors gave the altered virus to 12 patients, ages 7 to 18, whose cancer had worsened after usual treatments. Half also received a dose of radiation, which is believed to help spread the virus.
Eleven showed evidence in imaging tests or tissue samples that the treatment worked. Median survival was a little over a year – more than double what has been seen in the past.
As of last June – the close for analyzing these results – four were still alive, at least 18 months after treatment.
Tests also showed high levels of specialized immune system cells in their tumors. That suggests that the treatment had recruited the body’s help to attack the disease.
No serious safety concerns were observed, although there were several procedure-related complications and mild side effects, including nausea, vomiting, diarrhea and fatigue.
Only one comparable virus therapy for any cancer has been approved in the United States – Imlygic, also a modified herpes virus, for the treatment of melanoma, the most serious form of skin cancer.
Jake Kestler received the treatment when he was 12.
He lived another year and four months after that, “long enough to celebrate his bar mitzvah, go to Hawaii with his family and see a brother born,” said his father Josh Kestler, a financial service provider from Livingston, New Jersey.
Jake died on April 11, 2019, but “we have no regrets” about trying the treatment, said Kestler, who has started a foundation called Trail Blazers for Kids with his wife to conduct further research.
“It’s a devastating disease for these patients and their families,” said Dr. Antoni Ribas, a cancer specialist at UCLA who chairs the group hosting the conference.
Initial results suggest the virus treatment is helping, but they need to be verified in a larger study, which doctors are planning, Ribas said.
Friedman said studies are continuing in adults as well, and plans are in the works for other types of brain tumors in children.
US government grants and various foundations paid for the study, and several doctors involved have financial ties to Treovir.
This combination of microscope images shows immune cells in a child’s brain tumor before and after treatment that uses viruses to stimulate an immune system response to the cancer cells. The image on the right shows an increase in activated immune cells, indicated in brown. University of Alabama Birmingham via AP