Angiogenesis inhibitor improves brain tumor survival by redu...( The beneficial effects of anti-angio...),Health

The beneficial effects of anti-angiogenesis drugs in the treatment of the deadly brain tumors called glioblastomas appear to result primarily from reduction of edema the swelling of brain tissue and not from any direct anti-tumor effect, according to a study from Massachusetts General Hospital (MGH) researchers. Their report, to be published in the Journal of Clinical Oncology and receiving early online release, describes how treatment with the experimental drug cediranib reduced edema and improved survival in three mouse models of glioblastoma.

"Our findings suggest that antiangiogenesis therapy can increase patient survival even in the face of persistent tumor growth," says Rakesh K. Jain, PhD, director of the Steele Laboratory in the MGH Department of Radiation Oncology, the study's co-senior author. "In glioblastoma clinical trials, it is important to separate survival analysis from that of tumor response to therapy, since many factors combine to cause patient deaths."

Cediranib inhibits the potent angiogenesis factor VEGF, which is known to be abundantly present in glioblastomas and play a critical role in tumor blood vessel formation. A 2007 report from an ongoing clinical trial at the MGH Cancer Center found that the drug temporarily normalized abnormal, leaky blood vessels in glioblastomas that had recurred after surgery, radiation or chemotherapy reducing edema and apparently the size of the tumors. But the exact mechanism underlying the effects was unclear, since the imaging technology used to track tumor progression could not distinguish between effects on blood vessels and an actual reduction in tumor size.

"We frequently see beneficial effects from drugs in patients without fully understanding the mechanism of action," says A. Gregory Sorensen, MD, of the MGH Radiology Department and Martinos Center for Biomedical Imaging, co-senior author of the report.. "The fact that anti-VEGF agents seem to provide
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