Fenbendazole is an antiparasitic drug that has been used to treat parasitic infections in humans and animals. It is known to have a high absorption rate and low degree of toxicity. It is also generally well-tolerated by most species. However, this does not necessarily mean that it is safe for every species. Chocolate, for example, is well-tolerated in humans but can be fatal to dogs if consumed in large quantities.
There are some studies that show that fenbendazole can slow cancer cell growth in laboratory tests. However, there isn’t sufficient evidence from randomized clinical trials to prove that it can cure cancer in humans. As a result, the U.S. Food and Drug Administration hasn’t approved it for use as a cancer treatment.
A new study suggests that fenbendazole may help fight some forms of cancer by disrupting certain cellular processes that both viruses and some cancer cells rely on to grow and spread. The research, published Jan. 22 in Science Translational Medicine, was led by Stanford ChEM-H’s Medicinal Chemistry Knowledge Center Professor Christopher Glenn and supported by ViRx@Stanford, a National Institutes of Health-funded center focused on developing new cancer drugs.
Glenn’s team found that fenbendazole, also called Panacur C in the United States, disrupted cellular processes in tumors that allowed cancer cells to survive and grow. For example, fenbendazole interfered with the formation of microtubules in tumor cells, causing them to destabilize and break apart. The drug also interferred with the process that normally allows cancer cells to enter the cell cycle and divide.
The researchers also found that fenbendazole accelerated the death of tumor cells, and prevented them from growing and spreading. They believe that fenbendazole works by targeting the proteins that regulate a cancer cell’s cellular metabolism. Specifically, the drug binds to tubulin, preventing its synthesis. In doing so, it blocks the cell from entering the cell cycle and triggering mitotic catastrophe.
Other studies suggest that fenbendazole may also prevent the development of resistance to conventional cancer treatments. For example, it appears to stop the development of DNA mutations that can allow cancer cells to escape from chemotherapy.
While there is some evidence that fenbendazole can improve the effects of some conventional cancer therapies, the vast majority of cancer patients receive only standard care. As a result, the researchers don’t think that it is reasonable to suggest that fenbendazole could replace other therapies in most cases. Additionally, Tippens’ anecdotal experience isn’t reliable enough to reliably attribute his remission to the anthelmintic. There were likely other causes of his remission, including conventional cancer therapies, that aren’t being accounted for. If he’s really been cured by fenbendazole, it will be impossible to determine the exact mechanism of his improvement without further research. This would require randomized clinical trials with many more patients than Tippens’ small sample size. fenbendazole cancer treatment