Doctors seeking treatments for malignant brain tumors have found promise in the venom of scorpions, according to a study released on Friday.

The study showed that a synthetic version of a protein found in the venom of giant yellow Israeli scorpions targeted tumor cells but did not harm the healthy cells of brain cancer patients.

"We’re testing a new agent that has a lot of potential for patients who have had no meaningful treatments thus far," said Dr. Adam Mamelak, lead author on an article to appear in the August issue of the Journal of Clinical Oncology.
In the study, 18 patients first had surgery to remove malignant gliomas, a lethal kind of brain tumor. Then doctors injected their brains with a solution of radioactive iodine and TM-601, the synthetic protein.

The solution bound almost exclusively to leftover tumor cells, suggesting that it could be combined with chemotherapy to fight cancer. Furthermore, two study patients were still alive nearly three years after the treatment.

Because life expectancy for the 14,000 annual glioma patients in the United States is typically a matter of months, the results shore up animal research indicating that the venom protein may inhibit tumor growth even without a radioactive component, Mamelak said.

"Does that mean that the drug was miraculous? No," said Mamelak, a neurosurgeon at Cedars-Sinai Medical Center in Los Angeles. "But we have shown that it is safe and that we should at least move forward."

The synthetic scorpion venom was developed by Transmolecular Industries, Inc., a Boston-based company, and is one of several medicines recently derived from animal poisons.

Other researchers are investigating whether a protein in snake venom can stop bleeding and whether Gila monster venom can treat diabetes. They also have developed a painkiller based on the venom of a deadly sea snail.

Work with these proteins and molecules is the natural progression from previous science studying simpler plant extracts that have yielded key medicines, said Michael Egan, president of Transmolecular Industries.

"Evolution has had this stuff for a while, so chances are (animals) have a few things we can take advantage of," Egan said.

Giant yellow Israeli scorpions live in the deserts of the Middle East and grow to about 4 inches long.