Does Fenbendazole For Cancer Really Work?

A Canadian veterinarian’s viral TikTok video claiming the dog deworming drug fenbendazole cures cancer is misleading, according to researchers who have conducted studies that show it doesn’t work in humans. Although some preclinical studies are examining this drug for its potential anticancer effects, there is no proof it works in humans.

Cells establish shape and structure in large part through the protein scaffolding that binds cellular organelles and cargo and provides the foundation upon which other proteins can be added. A key component of this scaffolding is a highly dynamic system called microtubules, which are made of tubulin. Fenbendazole interferes with the formation of these structures by binding to a specific subunit of the tubulin molecule. As a result, it can inhibit a number of cellular functions, including cell growth and cell cycle progression.

We tested the hypothesis that fenbendazole would act as a radiosensitizer in hypoxic tumor cells and patient-derived colon cancer organoids by treating them with the compound prior to and during radiation. Cell survival in the presence of radiation was measured using a colony formation assay, and data were analyzed for differences between treatments. Treatment with fenbendazole did not significantly affect radiation dose-response curves in either aerobic or hypoxic cells.

To further examine the radiosensitizing effects of fenbendazole, we treated mice with tumors that grew to a volume four times greater than their initial size. We randomly assigned some mice to receive local tumor irradiation while others received fenbendazole. When tumors reached their target volume, they were euthanized and necropsied. No difference in the number of lung metastases was observed in mice that received fenbendazole and those that did not, both for unirradiated tumors and for mice that received local irradiation alone (p=0.44).fenbendazole for cancer