Virus boosts brain cancer patients’ lives
MD Anderson study reaffirms promise of immunotherapy
A cold virus that attacks tumor cells and triggers an immune response significantly extended the lives of a subset of patients with the deadliest form of brain cancer, according to a Houston study that provides another sign of immunotherapy’s promise.
The study, conducted by MD Anderson Cancer Center researchers, represents the first published evidence the radical-sounding experimental therapy — viral immunotherapy — may benefit select patients following the return of glioblastoma after surgery and other initial treatments.
“This opens up a potential therapy for a disease that has no good treatment,” said Dr. Freder--
ick Lang, MD Anderson’s chairman of neurosurgery and the study’s principal’s investigator. “And it does it with a natural virus that works in a unique way.”
Five of 25 patients in the trial lived three to five years after their cancer came back. The average survival for such patients is six months.
The results, published Monday in the Journal of Clinical Oncology, echoed those typically delivered by another type of immunotherapy that releases a brake on the immune system and allows it to go after cancer. Those drugs, pioneered by MD Anderson scientist Jim Allison, have become a new modality of cancer treatment even though they still only work in a minority of patients and cancers. They are known as checkpoint inhibitor drugs.
Glioblastoma thus far has defied checkpoint inhibitors, one reason the work with viruses isn’t considered so important. It is the most common and aggressive form of brain cancer — most patients live 15 months after the initial diagnosis. Glioblastoma killed former Sen. Edward Kennedy and former Delaware Attorney General Beau Biden, the son of former Vice President Joe Biden, and Sen. John McCain, RArizona, is currently undergoing treatment for it.
Sometimes called “grow-andgo” tumors, glioblastomas are lethal because they make their own blood supply, which fuels the tumors’ rapid growth and helps them hatch satellite tumors. Doctors compare them to a weed that keeps sprouting tendrils.
Historically, glioblastoma has been considered one of the least likely cancers to respond to immunotherapy.
Signifcant advancement
Dr. David Baskin, a Houston Methodist Hospital neurosurgeon also conducting research with viral immunotherapy, cautioned that MD Anderson’s findings will need to be replicated in a larger group of patients, but hailed the study as “very important” and said 20 percent of patients living longer is “very impressive and encouraging.”
“This study advances our knowledge of the field and the virus may be a very important discovery for treatment of patients with glioblastoma,” Baskin said.
“Minimal toxicity and a new gene-mediated immunotherapy is an exciting advance. It’s likely the investigators have developed something very important in the field of neuro-oncology.”
Baskin’s own research has produced what’s thought to be the greatest single success in brain cancer viral immunotherapy — a glioblastoma patient who has now survived 11 years. Among the patients benefitting from MD Anderson’s study was Phil Baumann, a Houston man whose glioblastoma came roaring back six months after the completion of surgery, radiation and chemotherapy. After a single injection of the virus, the tumor vanished and Baumann remained cancer-free for four years before it returned in the fall of 2015 and killed him in June 2017.
“You can’t escape glioblastoma,” Baumann said in a MD Anderson publication story after the cancer’s return. “I’m extremely blessed that I’ve been given extra time to be a husband and father.”
The MD Anderson virus was engineered to infect cancer cells, replicate inside them and kill them, then spread from cell to cell in a destructive wave. The study showed the virus achieved such results but also triggered an immune reaction in some patients.
It caused minimal side effects.
Virus breaks tumor’s shield
Baumann was one of three patients whose response was considered complete — imaging showed evidence of inflammation and immune activity a month after treatment, followed by a steady decline in tumor size until at least 95 percent of it disappeared, not to come back for at least three years. In two others who lived at least three years, it was unclear at some point whether the cancer returned or the imaging reflected inflammation produced by the immune system so they received additional treatment.
Lang said the virus breaks the tumor’s shield against cancer cells, creating targets for the immune system.
All 25 patients on the trial died, as those who had lasting immune responses eventually had recurrences. In two, that tumor that came back was glio-sarcoma, substantially different from glioblastoma.
Lang said he expects the results will improve in future trials because early patients were hampered by a primitive injection method and did not benefit from the optimum dose amount, not determined until more patients had been determined.
A new trial under way is combining the viral therapy with a checkpoint inhibitor drug.
The Food and Drug Administration in 2015 approved the first viral immunotherapy, a herpes-based drug, which was considered a huge milestone at the time. But that was for melanoma, the deadly skin cancer that responds well to different types of immunotherapy. Viral immunotherapy for brain cancer is still in early-stage research.