Fenbendazole is an anthelmintic drug used to treat various gastrointestinal parasites and has shown antitumor effects. It is thought to inhibit microtubule polymerization and block glucose uptake in cancer cells.
Recently, social media has spread claims that fenbendazole cured a woman with advanced non-small cell lung cancer. This medication is not FDA-approved for cancer treatment.
Safety
Fenbendazole is a widely used antiparasitic drug with a long history of use in many animal species. It is also a benzimidazole and has been shown to have anti-cancer activity. The drug is typically well tolerated in animals and does not cause significant side effects. However, it is important to discuss all medications with your veterinarian before administering them to your pet.
Researchers at Panjab University in India have found that fenbendazole, a broad-spectrum antiparasitic drug, could be useful in combating cancer. The team tested 17 different strains of C. neoformans and C. gattii for their susceptibility to fenbendazole using EUCAST assays. They found that all strains were similar in their susceptibility to the compound, suggesting that intrinsic resistance is not a factor. Furthermore, the researchers found that fenbendazole had very low toxicity to normal cells, making it an excellent candidate for development as an anti-cancer agent.
The research team also determined that fenbendazole reduced intracellular proliferation in phagocytized C. neoformans H99 and C. gattii R265 in macrophages. In vehicle-treated systems, fungal intracellular proliferation was seen as early as 1 h after phagocytosis, with more prominent peaks at 5 and 7 h. In drug-treated systems, fenbendazole reduced the intracellular proliferation rate of phagocytized cryptococci, showing that it was inhibiting the fungi’s ability to reproduce within host cells. This effect was comparable to that of cytotoxic anticancer agents.
Effectiveness
Fenbendazole is an antiparasitic drug that works by binding to b-tubulin microtubule subunits and disrupting their polymerization. This inhibits the formation of mitotic spindles, which help separate chromosomes during cell division (mitosis).
Studies have found that fenbendazole and drugs in this class can slow cancer cell growth in lab dishes and animals. However, there’s no sufficient evidence from randomized clinical trials that it can cure cancer.
A Facebook post by cancer patient Joe Tippens claimed that he used fenbendazole along with other conventional treatments and beat his Stage 4 cancer. But researchers who interviewed him say that he wasn’t treated in a randomized trial and can’t reliably attribute his improvement to the drug alone.
In fact, Tippens’ cancer recurred after he stopped taking the drug. Moreover, the Facebook post’s claim that fenbendazole prevents recurrent cancer is also unfounded. There’s no evidence that any established treatment, including chemotherapy, can prevent recurrent cancer.
Side Effects
Fenbendazole works by interfering with the formation of microtubules, which are a component of the protein scaffold that provides structure to all cells. Textbook depictions of cells commonly portray them as various cellular components floating in amorphous bags of liquid, but in reality cells establish shape and structure through the cytoskeleton, which is comprised of these microtubules. Cancer cells rely heavily on this cytoskeleton for survival and to transport organelles and cargo within the cell. Thus, when the cytoskeleton is disrupted by drugs like fenbendazole, the cell loses its structural integrity and is unable to move or function normally.
While fenbendazole does suppress cancer in laboratory cells and animals, this doesn’t prove that it can cure people. The drug doesn’t have a long track record in humans (the most recent published data is from 1976), and there is no evidence that it prevents recurrent cancer in human patients.
A specialist cancer information nurse from Cancer Research UK tells Full Fact that there isn’t enough evidence to show that fenbendazole kills cancer in humans. She also points out that Tippens’ anecdotal experience with fenbendazole isn’t statistically significant, and it’s impossible to know whether his remission would have occurred even without the treatment.
Regardless, veterinarians can legally prescribe certain human medications to their patients in certain circumstances. This is known as extra-label use, and fenbendazole is no exception. It’s available as a broad spectrum anthelmintic for cats, dogs, and horses under the brand names Pancur, Panacur C, and Safe-Guard.
Dosage
The Joe Tippens protocol recommends 222 mg of fenbendazole a day, seven days a week. This is the dosage used in veterinary medicine to treat helminth intestinal parasites and lungworms. It also works against nematodes, flukes, and giardia. The protocol also includes other ingredients and supplements.
This medication is usually well-tolerated by humans and has a high safety margin. It does not cause any adverse side effects in experimental animals, even when administered at several times the approved dosage. This makes it an ideal candidate for repurposing to become an anticancer drug, according to researchers.
There is no evidence that fenbendazole cures cancer, and the drug hasn’t been tested in humans during clinical trials. Its mechanism of action isn’t unique, and there are already established treatments that act in a similar way, such as chemotherapy and immunotherapies.
While the author of the TikTok and Facebook posts says that fenbendazole cured her of stage 4 lung cancer, she didn’t give any evidence to support her claim. The post was based on videos by Andrew Jones, a veterinarian from British Columbia. Jones is an unlicensed practitioner and has been reprimanded by the College of Veterinarians of BC for promoting alternative medicine. Jones has also resigned from his position as a member of the association. He cites the case of Joe Tippens, who claimed that he was cured of small-cell lung cancer after taking fenbendazole for humans