A tiny fat-based spherical structure called a liposome, modified at Duke to be sensitive to mild heating, can triple the amount of an anti-cancer drug delivered to tumors in mice compared to other liposome-based drug-delivery methods, Duke Medical Center researchers reported Thursday.

"Earlier this year we saw an improved therapeutic effect in animals, but didn't know exactly why," said Garheng Kong, lead author of the new study findings published in the Dec. 15 issue of Cancer Research. "Now we've shown that it's due to increasing the concentration of the drug in the tumor compared to the other treatments tested."

Because delivering anti-cancer drugs into tumors is one of the major hurdles in advancing potential drugs from the cell culture dish to clinical trials, this discovery could pave the way to improve the success of chemotherapy in humans, the researchers said.

"There are countless drugs that are very effective at killing cancer cells in the laboratory, but they act very differently in a living system many just won't go where you want them to go," said principal investigator Mark Dewhirst, director of Duke Comprehensive Cancer Center's Hyperthermia Program. "We're able to see an enhanced anti-tumor effect in mice with this new liposome because we're getting more drug into the tumor. This new liposome may eventually be applicable in cases where traditional chemotherapy is not effective."

While human studies are more than a year away, the results of the scientists' studies in mice differentiate the therapeutic importance of heat, liposomes and drug release and the interaction of these factors by measuring amounts of the chemotherapy drug doxorubicin delivered to tumors by 10 different treatments. The study was funded by the National Institutes of Health, the Department of Defense, an NIH Medical Scientist Training Grant and Celsion Corp., Columbia, Md.

Drugs enclosed in standard liposomes, which aren't sensitive to temperatu
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Contact: Joanna Downer
downe010@mc.duke.edu
919-684-4148
Duke University Medical Center
13-Dec-2000