Posted: Oct 4, 2010 9:30 PM
Oct. 4, 2010 -- A new vaccine for a deadly brain cancer known as glioblastoma doubled the survival time of patients, researchers from Duke University report.
Unlike other vaccines given to prevent disease, ''this vaccine is given when patients get the cancer," says researcher John Sampson, MD, PhD, the Robert H. and Gloria Wilkins Professor of Neurosurgery at Duke University Medical Center. In the future, however, he says, "it's conceivable a vaccine like this would be used to prevent [the cancer]."
The new vaccine, he says, "seems to be twice as good as the standard therapy alone." The results of the study are published in the Journal of Clinical Oncology.
Up to 20,000 people in the U.S. are diagnosed each year with glioblastoma, Sampson says. "It's the most deadly form of brain cancer. The average survival after diagnosis is a little more than a year. It hits people in their prime, such as a 50-year-old executive."
Sampson and other experts know that about one-third of all glioblastomas are fueled by a mutated protein on the tumor cell, called EGFRvIII (epidermal growth factor receptor variant III). EGFRvIII leads the cancer cells to grow out of control quickly.
''The vaccine creates antibodies specially programmed to attack this mutated protein on the tumor cell," Sampson says.
For the study, Sampson and his colleagues from Duke and the University of Texas M.D. Anderson Cancer Center in Houston enrolled 35 glioblastoma patients and divided them into two groups -- a vaccine group and a non-vaccine group.
Both groups got standard care -- surgery, radiation, and the chemotherapy drug temozolomide.
But those in the vaccine group also received injections of the vaccine a month after completing radiation, staying on the vaccine monthly for as long as it seemed to be working.
The addition of the vaccine lengthened the median survival time (half lived longer, half not as long) from the expected 15 months to 26 months.
Those who got the vaccine had a progression-free survival of 14.2 months, while those who didn't had a 6.3-month progression-free survival.
"Several patients are over five years out [from the diagnosis] now," Sampson tells WebMD.
Further study and FDA approval are needed before the vaccine can become commercially available, Sampson says. The new study is a phase II study, meant to evaluate effectiveness of a treatment as well as side effects and risks. Phase III studies look further at effectiveness as well as risks and benefits.
Adverse effects of the vaccine were minimal, Sampson says. "Occasionally patients will have a bit of an allergic reaction," he says. The vaccine is injected in the upper thigh.
The vaccine would not replace standard therapy, but supplement it, he says.
"We have some new evidence suggesting the vaccine and standard of care actually act synergistically, so it probably would be best to use them together," Sampson says.
As one of the vaccine developers, Sampson would have a financial interest in the vaccine should it become commercially available, he says.
While many other attempts for cancer vaccines are ongoing, the new vaccine approach is simpler than others, says Behnam Badie, MD, professor of neurosurgery and director of the brain tumor program at City of Hope Cancer Center in Duarte, Calif., who reviewed the findings for WebMD.
"His technique is less complicated, because it requires less manipulation in the lab and does not require tissue from the patient," Badie says.
But he has a few concerns. "Only 30% of [glioblastoma] tumors make this EGFRvIII variant," he says, a limitation cited by Sampson as well. So it wouldn't work well for all glioblastomas.
When tumors return, they don't make the variant anymore, Badie says, so the vaccine wouldn't be expected to work anymore.
Still, he calls the new findings ''very exciting."