Fenbendazole is a benzimidazole medication that has long been used in animal medicine to treat parasitic worms such as whipworms, hookworms and a single species of tapeworm (Taenia pisiformis). It has a good safety record for human use and is used at a dose of up to 1.5 g per person on a regular basis for human Ascaris, hookworm and tapeworm infections. It has also been shown to have powerful anti-neoplastic properties in laboratory experiments.
The benzimidazole family of drugs has been identified as having potential to enhance the effectiveness of radiation treatment, surgery and chemotherapeutic agents. In particular, fenbendazole for humans may be effective in boosting the efficacy of other antineoplastic drugs such as sodium dichloroacetate and vinca alkaloids by disrupting microtubule dynamics and blocking glucose uptake to starve cancer cells.
A number of clinical trials are currently underway to evaluate the anti-neoplastic effects of fenbendazole for humans. These trials will compare the effects of fenbendazole to those of standard chemotherapy such as carboplatin and gemcitabine in various types of cancer. The researchers will be looking to determine the effectiveness of fenbendazole for the prevention and treatment of metastatic cancer in patients with non-small cell lung carcinoma (NSCLC).
A case report of a patient with NSCLC who self-administered fenbendazole is reported. The patient and her family sourced information about this anti-cancer drug on social media websites, purchased the medication and orally self-administered it in order to try to improve her symptoms. This is the first known report of a cancer patient using a benzimidazole anthelmintic to treat their own illness and it provides an important reminder that physicians should question patients about self-administration of dietary supplements, herbal medicines or other nonprescribed products.
The article describes the experimental results of three experiments involving EMT6 tumor-bearing mice. These experiments compared the growth of EMT6 tumors treated with three daily i.p. injections of fenbendazole alone to untreated controls, or those that were treated with fenbendazole plus 10 Gy of x-rays. There were no significant differences in the growth of unirradiated or irradiated tumors, and fenbendazole did not alter the dose-response curve for either radiation or docetaxel.
It is not known exactly how fenbendazole acts against cancer cells but it is thought that the drug works by inhibiting the expression of GLUT 4 (glucose transporter isoform 4) in the cancer cells, thus restricting insulin-stimulated glucose uptake and starving the cells of glucose. This is the same mechanism by which the benzimidazole class of drugs interact with tubulin and cause its depolymerization. It is also possible that fenbendazole interferes with the formation of microtubules and blocks the movement of cyclin B1 from the cytoplasm to the nucleus. This halts the progression of cell division and causes the cell to die. The author concludes that fenbendazole is an anti-neoplastic agent for humans and should be evaluated further in combination with other antineoplastic therapies. Further studies should also be conducted to assess whether or not fenbendazole may have synergistic effects when combined with other cancer treatments such as surgery, radiation and berberine.