Venom back in vogue as a wellspring for drug candidates

Abstract

How a new wave of research on venoms from an array of creatures could seed future pharma development. Pediatric neurosurgeon Amy Lee works by the small, bright light of a microscope, her gaze focused on the opened skull of a child. Lee moves her hands calmly and confidently over the exposed brain, plucking out as much tumor as she safely can. A handful of promising new drug candidates are derived from peptides in the venom of scorpions and other animals. Image credit: Shutterstock/Bens_Hikes. But there are some surgeries, and some parts of the brain, where tumor tissue and healthy tissue look very much alike. In those cases, Lee, based at Seattle Children’s Hospital in Washington, looks to a computer monitor beside the operating table, where a view of the brain shows tumor, illuminated in fluorescent green, nestled in otherwise white, healthy tissue. This new diagnostic tool helps surgeons gauge, in real time, how much tumor they’ve removed, and how much is left behind. That green glow comes from tozuleristide, a new diagnostic drug in phase two clinical trials. But the drug’s novelty stems not only from its potential to highlight troublesome childhood tumors, but also from the compound’s source: the potent venom of the Israeli deathstalker scorpion ( Leiurus quinquestriatus ). Tozuleristide uses a peptide from the venom and an infrared dye to seek out and illuminate tumors of all kinds, including in the breast, colon, and skin. The drug has gone through safety testing and early clinical trials to image brain tumors in children, and today stands about two years from possible US Food and Drug Administration (FDA) approval. The key ingredient, the scorpion venom peptide chlorotoxin, is just one of many untapped, and potentially lifesaving toxins in the venom of snakes, scorpions, spiders, and other creatures, honed through millions …