A video circulating on TikTok and Facebook claims that a drug commonly used to treat parasites in animals, fenbendazole (commonly called Mebendazole), cures cancer. While some preclinical studies are examining this class of drugs as potential anti-cancer therapies, there has been no proof that they work in humans. As a specialist cancer information nurse at Cancer Research UK told Full Fact, if a treatment shows promise in cell or animal models, it must go through rigorous clinical trials to prove that it will also work for human patients.
Veterinary medications are often overlooked as potential sources of promising new drugs for human diseases, but repurposing existing treatments can save time and money in the development process. For example, a recent study published in Scientific Reports found that the compounded medication fenbendazole is effective in killing human non-small cell lung cancer cells by targeting microtubule structures in the cancerous cells.
The authors of the study conducted a series of experiments on the human NSCLC cell lines SNU-C5 and SNU-C5/5-FUR to determine whether fenbendazole caused cancerous cell death by disrupting the mitotic spindle. Mitosis is a crucial cell division process that ensures that each daughter cell receives equal amounts of genetic material during cell reproduction. Mitosis is driven by a structure called the mitotic spindle, which contains microtubules that are held in place by proteins. The team found that fenbendazole, like other drugs in this class, inhibited cancer cell growth by destabilizing the mitotic spindle and causing chromosome segregation to stop.
In addition to its anti-mitotic activity, fenbendazole induced apoptosis in the cancerous cells through multiple pathways. It induced autophagy and ferroptosis, both of which are mechanisms that lead to cell death, in SNU-C5 and SNU-C5/5-FUR cells. It also lowered glucose uptake and enhanced caspase-8 activation in the former. The scientists observed reduced tumour volume in mice that were fed fenbendazole for 12 days.
These findings suggest that fenbendazole could be used in conjunction with other conventional cancer treatments, such as chemotherapy and radiation, to enhance their effectiveness. The researchers also found that fenbendazole did not show any major side effects in normal mice.
In their paper, the authors note that a drug’s effect on human disease must be proven in clinical trials and that it is important to have a well-defined patient population before attempting to translate results from animal models into clinical practice. This is one of the many obstacles to successful translation of science to medicine.
The researchers conclude by saying that fenbendazole can be easily administered via mouth or intravenous injection and is generally well tolerated in different species of animals at doses several times larger than the approved therapeutic dose. This low toxicity profile, combined with the evidence that the compound inhibits human NSCLC growth and metastasis, make it an attractive candidate for repurposing as an anticancer drug.
The TikTok and Facebook videos that claim fenbendazole cures cancer take clips from a 2019 YouTube video from a Canadian veterinarian, Dr. David Jones, that featured Joe Tippens, a man who claimed to be diagnosed with terminal lung cancer and then treated successfully with fenbendazole, in addition to other cancer-fighting medicines. Tippens’ story was widely reported in the media, but researchers have not been able to replicate his case or prove that fenbendazole alone is effective against cancer. fenbendazole cures cancer