ZYBRESTAT (combretastatin) kills tumors by attacking the blood vessels that
supply them with oxygen and nutrients.
After a short intravenous infusion, ZYBRESTAT rapidly spreads throughout the patient's
bloodstream. It is then converted to its active form, combretastatin, which enters the
endothelial cells that line the blood vessels. In tumors, these cells are
immature and thus particularly sensitive to combretastatin's effects as compared to
the endothelial cells in normal tissue.
Once inside the endothelial cells lining the tumor vasculature, combretastatin destroys the internal skeleton
of the cells and changes their shape from flat to round, effectively plugging
the capillaries that feed the tumors.
This theory was initially demonstrated, via blood-flow imaging, in Phase I clinical trials of
cancer patients with solid tumors. Blood-flow imaging measurements demonstrated statitically significant
reductions in tumor blood-flow four to six hours following the
infusion of ZYBRESTAT.
