Cancer Updates Dec Issue Final-16006_Cancer_Updates_Dec_Issue_F4_spreads | Page 16

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“There are infiltrating tumor cells even in brain tissue that appear perfectly
normal,” Dr. Fink said. “There’s almost always microscopic tumor left, and
we have limited treatments for tumors that recur.”
The short list of drugs approved for recurring GBM includes temozolomide,
carboplatin, irinotecan, bevacizumab and lomustine.
“We’re always looking for better therapeutics, because the results of these
drugs are disappointing for patients with recurrent GBM,” said Dr. Fink,
noting that median survival for recurring GBM is only 6 months.
New clinical trials using vaccines for glioblastoma at Baylor
University Medical Center at Dallas
Now, using immune therapies, several clinical trials have recently started
at Baylor University Medical Center at Dallas and are providing new
opportunities for patients with brain cancer. “The hope is, by giving vaccines,
we can harness the immune system to attack glioblastoma. In the past,
the immune system has not
been felt to play much of a
role in fighting glioblastoma,
but more recently we have
realized that we may be
able to rev up the immune
system by giving it a target to
recognize,” said Dr. Fink. “The
Karen Fink, MD, PhD
vaccine trials we have open
Medical Director of Neuro-oncology
at Baylor University Medical
Center try to get the patient’s immune system to recognize and kill the
tumor cells and to provide protection against tumor recurrence.
The hope is, by giving
vaccines, we can harness
the immune system to
attack glioblastoma.
“After a vaccine, the immune system can seek out and destroy brain tumor
cells that we can’t even necessarily see on scans or at surgery. The body
itself should help eliminate those abnormal cells,” said Dr. Fink.
One clinical trial that began this year involves a vaccine called ICT-121 for
GBM patients with recurrent tumors. The treatment primes the patient’s
immune system to recognize CD-133, which is a marker that is present on
many hematopoietic and progenitor stem cells, including many cancer stem
cells. The presence of CD-133 on cancer cells is associated with resistance
to chemotherapy and survival of the cancer cells.
“Stem cells are the cells within our body that rejuvenate and regenerate our
tissues. They’re pretty rare. But in glioblastomas, they are the cells that are
more resistant to chemotherapy, and they are the ones that we think lead
the glioblastoma to keep recurring,” Dr. Fink said.
Dendritic cells are removed from the blood of a patient, then sensitized,
or pulsed, with CD-133. These activated dendritic cells are then given
back to the patient as a series of vaccine injections—once a week for a
month, and then once every two months. “The CD-133–sensitized dendritic
cells recognize the GBM stem cells and recruit the rest of the immune
system to destroy those stem cells, which is how we hope to eradicate the
glioblastoma,” Dr. Fink said.
About 100 patients will be enrolled nationwide in this clinical trial, including
patients at Baylor University Medical Center at Dallas. Like other brain
cancer clinical trials, this study involves multiple sites so that a sufficient
number of patients with this rare disease can be analyzed and enough
evidence can be collected to make valid conclusions.
Patients in this clinical trial may not have been on the drug bevacizumab
(Avastin ® ) and cannot be receiving a steroid dose more than four
milligrams per day.
Phase 3 Clinical Trial Vaccine
Aimed at Newly Diagnosed Patients
Another brain cancer clinical trial, a
phase 3 study called ICT-107, began in
September at Baylor University Medical
Center at Dallas as a frontline treatment
against GBM tumors. This clinical trial
also uses a patient’s dendritic cells but
sensitizes them against six different
tumor antigens. “The idea is, if you
expose the dendritic cells to more
antigens, they’re more likely to be more
effective when they’re put back into the
body,” Dr. Fink said. Phase 2 testing,
which was also conducted at Baylor
University Medical Center at Dallas,
showed that this vaccine was well-
tolerated by patients.
Both the ITC-121 and ITC-107 clinical trials are complicated by a
requirement that patients have a particular blood subtype known as HLA-A2,
which correlates with a particular immune response. This subtype is found
in about 30 percent to 40 percent of the populace.
“We’ve made strides against brain cancer in the last couple of decades,
and people are living longer,” Dr. Fink said. “We have hope that these new
immune system vaccines will be more effective against GBM and will
provide another weapon to aim at these aggressive tumors.”