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Experimental Drug Gives New Hope For Brain Cancer
Kim Mulvihill, M.D.
Reporting
An experimental drug is saving the lives of patients with an aggressive form of brain cancer.
Dave Herbert is alive today because of the high-tech drug. Just five years ago, he was diagnosed and treated for a potentially deadly brain tumor -- a glioblastoma. These tumors have tentacles that spread and mix with normal brain tissue. Even with aggressive treatment, most patients live less than a year. Herbert´s doctor told him that he probably had six months to live.
"Typically, radiation combined with the chemotherapy will control the tumor for about six to eight months before it comes back," said Dr. Sandeep Kunwar, a neurosurgeon at UCSF. "All patients recur."
So Herbert decided to try an experimental drug at UCSF Medical Center -- a drug never before used on humans. Three holes were drilled into Dave´s skull, and three catheters the size of angel-hair pasta were inserted into the holes, bypassing what´s called the blood brain barrier. This barrier, which keeps chemo drugs out, ironically keeps this high tech drug in.
"It´s the blood brain barrier that was our very enemy now is our friend in able to deliver the drug," said Kunwar.
The drug, called IL-13 P-38 was slowly infused into Herbert´s brain over four days. It´s a targeted therapy that carries a deadly bacterial toxin.
"It´s very potent," said Kunwar. "One or a few molecules can kill, actually kill a tumor cell and it´s very selective."
The drug binds to a protein -- a receptor -- found only in brain cancer cells. Once the drug locks on, the toxin enters the cancer cell and kills it. The drug cannot lock onto or hurt healthy cells in the brain.
Doctors now can´t find any evidence of tumor in Herbert´s brain. About 25% to 30% of patients treated with IL-13 P-38 will have the same exceptional outcome, with no tumor returning. The UCSF scientists are trying to figure out why it works for some people and not others.
Aug 16, 2005 4:31 pm US/Pacific
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