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BODY & BRAIN
Poliovirus helps
fight brain cancer
Treatment increased survival
in some glioblastoma patients
BY AIMEE CUNNINGHAM
Few treatment options are available for
people facing a second battle with a particularly fatal type of brain tumor called
glioblastoma. But dosing the tumor with
a genetically modified poliovirus — one
that doesn’t cause the eponymous, devastating disease — may give these patients
more time, a small clinical study suggests.
Of 61 people with recurring glioblastoma who were treated with the modified
virus, 21 percent were alive after three
years. In a “historical” comparison
group of 104 patients who would have
been eligible for the treatment but died
before it was available, 4 percent lived as
long, researchers report online June 26
in the New England Journal of Medicine.
Two patients who received the altered
virus are still alive six years after treat-
ment. “They’ve been able to lead largely
normal lives, and we almost never see
that with these brain tumors,” says
neuro-oncologist Darell Bigner of Duke
University Medical Center.
Standard treatment for glioblastoma
is surgery, radiation and chemotherapy,
Bigner says. Usually patients do not survive longer than 20 months after being
diagnosed; those with a recurrence typically live less than a year.
Poliovirus, which can cause paralysis
and death, infects nerve cells by connecting with a cell surface protein that
also appears on tumor cells. In previous
work, the Duke research team swapped
out the genetic machinery that lets the
virus commandeer and destroy nerve
cells with a piece of a virus that causes
the common cold. This change didn’t
prevent the poliovirus from killing
tumor cells. And the treatment triggered
the immune system to target the cancer.
In the new study, the team delivered
the virus directly into patients’ tumors
via a tube traversing the skull. None of
the patients developed polio symptoms.
Both people who have survived for six
years developed glioblastoma again, but
were successfully treated a second time.
“There doesn’t seem to be any resistance
to re-treatment,” Bigner says.
Bigner’s group plans to study the
effects of combining the poliovirus treatment with drugs that may further boost
the immune response against the cancer.
“We must be optimistic, but with
caution,” says neurosurgical oncolo-gist E. Antonio Chiocca of Brigham
and Women’s Hospital in Boston. “The
history of glioblastoma treatments is
littered with lots of early clinical trials
that appear to show very promising and
encouraging results,” but don’t prove to
be useful in later trials. s
A patient’s glioblastoma tumor (upper left on MRI scans) shrank after a dose with a modified
poliovirus. The bottom right image shows the tumor nearly five years after treatment.
BODY & BRAIN
Sex among U.S. teens is on the decline
But fewer sexually active high school kids are using condoms
BY AIMEE CUNNINGHAM
Fewer teens are having sex than at any
point since 1991, a survey of U.S. high
school students finds. Among those students who are sexually active, fewer are
using condoms, raising the risk of contracting sexually transmitted infections.
About 40 percent of teens surveyed in
2017 reported having ever had sex. That’s
down from about 54 percent in 1991, the
first year the survey was conducted. Of
the roughly 29 percent of students who
are currently sexually active — defined
as having had sexual intercourse in the
three months before the survey — nearly
54 percent reported that either they
or their partner used a condom the last
time they had sex. Ten years ago, about
62 percent of teens reported condom use.
Cora Breuner, a pediatrician at Seattle
Children’s Hospital, says doctors have
been doing a better job educating teens
about sex. “The more kids know about it,
the less mystique there is about it,” she
says, and “the more they want to wait.”
Breuner sees two reasons for the drop
in condom use: less fear of HIV with the
advent of antiretroviral drugs and wider
availability of long-acting contraceptives.
“We are not doing a good job informing
kids about protecting themselves from
getting sick with infections that can last
the rest of their lives and have significant
negative outcomes,” she says.
The new analysis, released June 14 by
the U.S. Centers for Disease Control and
Prevention, relied on nearly 15,000 surveys from teenagers at 144 high schools. s
