A drug that triples survival rate
for high-grade gliomas is safe enough to become the
firstline therapy for this nearly impossible-to-treat
cancer. Bevacizumab, an anti-angiogenesis drug that's
used for colorectal and other cancers, is safe and effective
when used with chemo and radiation, New York University
oncologist Dr Ashwatha Narayana told delegates at the
annual meeting of the American Society for Therapeutic
Radiology and Oncology in November in Los Angeles.
"We're very excited that, for the
very first time in over three years, we're making any
kind of progress in treating this cancer, which has
a two-year survival rate of hardly 5%," Dr Narayana
told NRM. He hopes the study will lead the FDA
to approve bevacizumab as a frontline management for
high-grade gliomas. These malignant brain tumours are
incurable and recur in almost all patients within a
year of treatment. "Even in a recurrent setting, we're
showing that we can improve the survival for these patients
and increase their quality of life," adds Dr Narayana.
BETTER
SURVIVAL
In Dr Narayana's study, which appeared in a supplement
of the International Journal of Radiation Oncology
Biology Physics in November, 14 high-grade glioma
patients (three recurrent and 11 biopsy only) were treated
with radiation therapy, chemo drug temozolomide and
bevacizumab. Changes in relative cerebral blood volume,
perfusion-permeability index and tumour volume were
measured to assess the therapeutic response.
After six months, only four of
the 14 patients had a cancer relapse, three of them
at the primary site, where the tumour was first detected,
and one of them at a different site. The latter patient
succumbed to the disease. The six month progression-free
survival and overall survival were 71% and 92%, respectively
— nearly triple the expected survival with this
cancer. Side effects were relatively minor and did not
include cerebral hemorrhaging, which is a risk with
bevacizumab.
TREATMENT
FUTURE
"We're cautiously optimistic," says Dr Narayana. His
team showed that bevacizumab diminished tumour recurrence
at the primary site and enhanced the effect of chemo
and radiation therapies. But in patients where the cancer
recurred, it cropped up in a different part of the brain.
"This isn't the usual pattern of failure, which leaves
us somewhat concerned," he adds.
In attempting to use the drug to
treat gliomas, Dr Narayana says he's trying to decide
where to draw the line between its effectiveness and
complications. "Essentially, what is the optimal dose?
Do we have to hold back radiation when administering
bevacizumab, and what is the best timing for treatment
— before, concurrent or after? Do we continue a
patient on anti-angiogenic treatment after they're stopped
radiation therapy? There are still a lot more questions
than answers," he says.
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