In his lab at the Mayo Clinic, cancer researcher Paul Moertel had come to despise drug companies. They spent more on marketing than research, he felt, and often pushed “me too drugs” that duplicated what was already out there. They took advantage of a captive market. And they charged way too much for their drugs.
Then Moertel heard something extraordinary. His colleagues were reporting that a deworming pill, levamisole, had remarkable effects on human tumors. When taken along with standard care, a drug called sorafenib, it cut the recurrence of advanced stage liver cancer by 41% and reduced the death rate by 33% in patients.
It’s an impressive result, but it’s also unproven. In fact, the claim that a dog dewormer can cure cancer is making waves online, with viral TikTok videos and Facebook posts from people who say they’ve used the medication to cure their cancers. Those claims are false, according to experts.
The medication at the center of this flurry is a cheap, widely used veterinary medicine, fenbendazole, better known as Panacur C, which is sold over-the-counter for parasites in dogs and cats. It’s part of a class of pharmaceuticals called anthelminthic benzimidazole carbamate (BZ) drugs, and it has long been known to work against a certain type of tapeworm in humans and animals. It’s also been shown to prevent the growth of microtubules, which give structure to cells, in living things and in mouse models. These properties are why Moertel and his team were so excited when they found that fenbendazole suppressed cancerous human liver tissue engrafted in mice. dewormer for cancer