SCIENCE FROM NATURE: Medical science has long turned to nature for cures and treatments. Aspirin, in fact, is a derivative of a particular kind of tree bark. While many modern drugs owe their existence to various trees and plants, the study of insect venom for medicinal purposes is somewhat less prominent, at least in the industrialized world.
STINGING CANCER: Researchers at the City of Hope Medical Center near Los Angeles and the University of Alabama at Birmingham are studying a particular strain of scorpion venom as a possible treatment for brain cancer. Glioma tumors make up two thirds of malignant brain tumors, and are almost always fatal. The average prognosis for a patient with a stage-four malignant glioma is just 55 weeks. One reason that gliomas are so deadly is that they tend to invade surrounding brain tissue, making complete removal through surgery very difficult. Chemotherapy and radiation typically prove equally inadequate.
Researchers studying the venom from the Israeli yellow scorpion noticed something significant about the compound. When injected into the brains of glioma patients, the toxin rapidly adhered to the cancer cells, but did not bond to healthy tissue. Although there was no evidence the venom itself killed tumor cells, scientists hoped that the venom's toxin, when copied in mass quantities in a laboratory, could be used as a vehicle on which to attach known cancer-killing substances.
The researchers began an early phase trial using glioma patients who had experienced recurrence. Doctors operated on six patients in all, cutting out whatever recurrent tumor cells could be safely removed. Then, each patient was fitted with a small catheter into the brain, through which a single injection of scorpion-based toxin was injected. A radioactive compound known for its ability to kill cancer cells was mixed with the toxin.
Just as researchers hoped, MRI's revealed that the toxin, along with the radioactive compound, had bonded directly to the remaining cancer cells, without spreading to surrounding healthy tissue. The toxin appeared to be directing the radioactivity precisely to the cancer, without allowing it to affect normal brain cells.
HOW SUCCESSFUL? To date, eight patients have been treated and all but one are alive. Doctors insist it is extremely premature to declare the scorpion venom trials successful, although it does seem to be clear that the procedure is safe and free of adverse side effects. It's not clear when, or even if, the toxin treatment will be approved for general use. Adam Mamelak, M.D., of City of Hope, says this kind of "targeted therapy" may well be the treatment of choice in the future.
"I'm hopeful that it's a step in the right direction," said Dr. Mamelak.
FOR MORE INFORMATION, PLEASE CONTACT:
City of Hope Medical Center
1500 E. Duarte Road
Duarte, CA 91010
(626) 359-8111 x64516