Frontier: Venom Targets Tumors

by Elizabeth Norton Lasley

September, 2006

Gliomas are among the deadliest of brain tumors; only 8 percent of patients survive longer than two years. A recent clinical trial suggests a highly effective treatment from an unusual source: a synthetic version of scorpion venom.

This peptide, or protein fragment, has been studied since the mid 1990s as a therapy for glioma because it safely targets a specific gate in the cell membrane that is plentiful in glioma cells but is not found in healthy brain tissue or other organs.

In the August Journal of Clinical Oncology, neurosurgeon Adam Mamelak at Cedars-Sinai Medical Center and colleagues attached the peptide, TM-601, to a small amount of radioactive iodine. Working with 18 patients who had undergone surgery to remove recurrent glioma, the researchers delivered the treatment through a small tube into the cavity left by the tumor.

The approach used TM-601’s affinity for cancer cells to deliver radiation therapy directly to the site of the tumor, sparing the rest of the brain and body from harmful side effects.

The results offer hope that the treatment is safe and effective: Two patients showed no evidence of residual cancer cells in MRI scans and were still alive almost three years after the study. A larger clinical trial is now under way.

“We used TM-601 primarily as a carrier, but other studies show that it may have its own ability to impede cancer growth,” Mamelak notes. “If so, the approach could be used to deliver chemotherapy as well.”