While anthelmintics used to treat parasites in animals are being studied as potential cancer treatments, no peer-reviewed study has found evidence that they can cure human cancer. The drug fenbendazole interferes with the formation of microtubules, which are components of the protein scaffold that gives cells their shape and provides highways for transporting organelles and cargo.
The nonprofit Cancer Research UK tells Full Fact that there’s no evidence fenbendazole can cure cancer. It’s an antiparasitic medication that’s been used to treat parasites in dogs, and it hasn’t gone through any clinical trials in humans to see if it’s effective against cancer. In addition, Joe Tippens, the man who claimed taking fenbendazole and other supplements cured his cancer, was also in a clinical trial for a chemotherapy treatment when he made that claim on social media.
There are, however, a few studies that show fenbendazole can suppress cancer cells in cell cultures and mice. It appears to work by blocking the proper growth of microtubules, which give structure to all living cells. These microtubules are important for the growth of cancer cells, so preventing them from growing could help kill the tumors.
Another study showed that fenbendazole can make paclitaxel, an approved drug for treating some types of cancer, more effective against resistant tumors. Researchers found that combining fenbendazole with paclitaxel caused the cancer to grow more slowly and stop multiplying.
In cell culture studies, fenbendazole decreased the survival of EMT6 mouse mammary tumor cells in severe hypoxia. This effect was not reversed by exposing the cultures to oxygen, suggesting that it is independent of oxygenation status. In vivo experiments, fenbendazole reduced the growth of paclitaxel-resistant tumors in mice. It did not, however, affect the dose-response curves for radiation or docetaxel, indicating that it does not significantly increase the antitumor effects of these drugs.
Another study found that mebendazole, a similar antiparasitic drug to fenbendazole, can slow pancreatic cancer progression in genetically engineered mice. Like fenbendazole, mebendazole works by cutting off the supply of nutrition to cancer cells by inhibiting tubulin formation. The cancer cells are then starved to death. Mebendazole may have other ways to help fight cancer as well, such as reducing inflammation and preventing tumors from forming new blood vessels.
Fenbendazole and other drugs of this class kill parasites by interfering with the formation of microtubules, structures which help give shape to cells. Cancer cells also use microtubules, and disrupting their function can lead to a loss of structure that stops the cell from functioning properly.
When paired with chemotherapy drugs, fenbendazole increases the effectiveness of the drug by blocking certain processes required for cell division, such as the separation of duplicated chromosomes during mitosis (see the picture above). This means that fewer healthy cells will be affected by the drug, which will reduce side effects and increase treatment efficiency.
In experiments with EMT6 tumors in BALB/c mice, fenbendazole had no effect on the growth of unirradiated tumors, but was able to block the radiosensitivity of these tumors when given a few hours before or during radiation (see Figure 3). The 2 and 24-h treatments were equally toxic to aerobic and hypoxic cultures of the cell line, and caused clonogenicity reductions equal to those of irradiation alone.
The experiments compared the growth of EMT6 tumors in treated and control mice, and found that the tumors were significantly less likely to reach the target volume when they had been treated with fenbendazole and x-rays. The results of the experiment support the hypothesis that fenbendazole inhibits radiosensitivity by interfering with tubulin microtubules.
It’s important to note that although fenbendazole is an effective parasite killer, it has never been tested as a cancer cure in humans. As a specialist cancer information nurse at Cancer Research UK told Full Fact, there is insufficient evidence to find out whether fenbendazole can cure cancer, and the drug hasn’t gone through any clinical trials to determine its safety for human use. However, this does not mean that fenbendazole can’t eventually be used as a cancer treatment; the process of turning testing results into approved medications is long and complicated. fenbendazole for humans cancer