Since Botox is used in clinics without serious toxicity, the study indicates the possibility for human trials. In addition, dosages used in the mouse study were within the range used with humans in clinical settings. The toxin is administered inside the tumor with very limited diffusion into normal tissues, which may limit the amount of damage to normal cells in proximity to the tumor.
"This is the first experimental model demonstrating how Botox can affect the reaction of blood vessels that feed tumors," said Gallez. "Tumor microvessels are formed hastily, and lack smooth muscle layers, but one can find mature blood vessels, with smooth muscle layers that respond to toxins like Botulinun, inside tumors. Several laboratories, including ours, are working on new strategies to alleviate tumor hypoxia, which sensitizes the tumor to treatment. Botox appears to offer the advantage of selectivity, absence of toxicity and persistence for a longer time than other agents that act on tumor vasculature. Further research may help us determine whether this approach would be useful to treating cancer in humans."
The Gallez study was conducted by Réginald Ansiaux, Christine Baudelet, Greg Cron, Jérôme Segers, Chantal Dessy, Philippe Martinive, Julie De Wever, Julien Verrax, Valérie Wauthier, Nelson Beghein, Vincent Grégoire, Pedro Buc Calderon, and Olivier Feron, all of the Université de Louvain.