Next Cancer Treatments to Target Blood Supply
New Generation of Cancer Drugs Shows Promise in Starving Tumors
May 10, 2004 -- A new approach in cancer treatment that uses
drugs designed to cut off the tumor's blood supply may soon become a valuable
tool in improving existing cancer therapies.
The treatment involves using drugs that target and destroy
blood vessel networks within the tumor to starve it of oxygen and other vital
nutrients, which prevents further growth as well as promotes cell death within
the tumor itself. These blood vessel networks also provide the opportunity for
tumor cells to spread.
A review of recent research on the experimental approach
suggests this group of drugs, known as vascular-disrupting agents (VDAs), have
been proven effective in early, phase I clinical trials. As this class of
cancer drugs moves into phase II clinical trials, researchers say they will
likely prove most successful when used in combination with conventional
chemotherapy and radiation therapy.
New Approach in Cancer Treatment
Researchers say two different approaches in targeting blood
vessel networks within tumors are currently under investigation. The first,
known as angiogenic inhibitor treatment, aims to prevent the formation of new
blood vessel networks within the tumor, and the drugs are given continually
over months or years.
The second approach uses VDAs that are designed to destroy the
already established blood vessel networks within a tumor and are given for
short periods of time.
In their review of studies on VDAs appearing in the current
issue of the journal Cancer, researchers report that this approach has
produced exciting results in cutting off the blood supply to tumors and
inducing cell death within the tumor in animal and laboratory tests.
In addition, use of VDAs in combination with radiation and
other forms of chemotherapy has improved treatment outcomes in early human
tests. These drugs also appear safe for use in combination with these
conventional cancer treatments.
Phase II clinical trials of VDAs in humans are currently under
way, and researchers say they will determine whether these early successes in
the lab will carry over to humans.
"Time will tell whether the exciting preclinical findings
made using VDAs will be applicable in humans as well," writes researcher
Dietmar W. Siemann, PhD, of the University of Florida, and colleagues.