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ED drugs help chemotherapy get to brain tumors

Researchers found erectile dysfunction drugs increased the delivery of cancer-fighting drugs to malignant brain tumors in laboratory rats by opening the blood-brain tumor barrier.

The recent experiments were published in Brain Research.

Levitra and Viagra block the PDE5 enzyme (phosphodiesterase5), which interrupts the biochemical events that cause the decreased blood flow of erectile dysfunction. Those conducting the experiments at the Maxine Dunitz Neurosurgical Institute found the inhibitors had a unique effect on the blood-brain tumor barrier, which blocks anti-tumor drugs from getting to tumors. The ED drugs - particularly Levitra (vardenafil) - allowed increased drug transport to the tumors without affecting the rats' normal brain tissues.

"The combination of vardenafil and adriamycin (an anti-tumor drug unable to cross the blood-brain tumor barrier) resulted in longer survival and smaller tumor size," said Dr. Keith L. Black, chairman of Cedar-Sinai's Department of Neurosurgery and director of the neurosurgical institute.

Dr. Black, the article's first and corresponding author, did earlier groundbreaking work with natural and synthetic bradykinin, a peptide that temporarily opens the tumor barrier and increases drug-delivery by more than 1,000 percent.

In the PDE5 studies, the barrier-opening effects lasted considerably longer than those achieved using bradykinin.