Scorpion Venom Transports Radioactive Iodine to Tumours

Scorpion venom used for delivery
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Adam N. Mamelak, M.D., a neurosurgeon at Cedars-Sinai Medical Center’s Maxine Dunitz Neurosurgical Institute, Los Angeles, led the Phase I trial. The key ingredient is TM-601, a synthetic version of a peptide that naturally occurs in the venom of the Giant Yellow Israeli scorpion. TM-601 binds to glioma cells and has an unusual ability to pass through the blood-brain barrier that blocks most substances from reaching brain tissue from the bloodstream.

Patients who consented to participate in the Phase I study first underwent tumour-removal surgery. Fourteen to 28 days later, a single, low dose of radioactive iodine (131I) attached to TM-601 was injected through a small tube into the cavity from which the tumour had been removed.

Although TM-601 had been tested in earlier laboratory and animal experiments, it had never been given to humans. Therefore, the primary objective of this study was to document that 131I-TM-601 could be administered to humans safely. In addition, the researchers sought to begin to assess the drug’s anti-tumour effect and dosing standards. Six patients agreed to receive additional doses at one of three different levels (.25 mg. of TM-601, .5 mg. of TM-601, and 1 mg. of TM-601, each carrying the same amount of iodine).

“In this first human trial, treatment of patients with recurrent high-grade glioma with a single intracavitary dose of 131I-TM-601 was well tolerated to the maximum dose. Very few adverse side effects occurred during the initial 22-day observation period, suggesting the dosing level of peptide used in this study is safe and well-tolerated in humans,” the article states.

While median length of survival for all patients was 27 weeks, two patients, women in their early 40s, had a “complete radiographic response,” meaning there was no evidence of residual tumour according to magnetic resonance imaging scans.

MEDICA.de; Source: Cedars-Sinai Medical Center