Oral Fenbendazole for Cancer Therapy in Humans and Animals

Tania Sultana 1, Umair Jan 1, Jeong Ik Lee PMID: 35457127

Fenbendazole is a benzimidazole anthelmintic agent commonly used to treat animal parasitic infections. In humans, other benzimidazoles, such as mebendazole and albendazole, are used as antiparasitic agents. Since fenbendazole is not currently approved by the FDA or EMA, its pharmacokinetics and safety in humans have yet to be well-documented in medical literature.

Fenbendazole, also known as methyl N-(6-phenylsulfanyl-1H-benzimidazole-2yl), is currently used as an antiparasitic therapeutic agent in dogs and other animals. In humans, other benzimidazoles, such as mebendazole and albendazole, are used as antiparasitic agents (1).

Fenbendazole exerts its antiparasitic effects primarily in the anterior intestine by depolymerizing microtubules, inhibiting intestinal secretory vesicle transport. Fenbendazole binds to beta-tubulin in parasites, causing microtubule destabilization and hindering tubulin polymerization. This destabilization disrupts cellular function, such as glucose uptake, thereby affecting the energy management of parasites. Due to its poor absorption by oral administration, fenbendazole is particularly effective for targeting intestinal parasites (2).

In August 2016, fenbendazole garnered global attention as a potential anti-cancer therapy following the complete recovery success story of Joe Tippens, who was diagnosed with small-cell lung cancer. At the time, Tippens was undergoing a clinical trial for a novel anti-cancer drug.

Meanwhile, under the guidance of a veterinarian, Tippens began self-administering 222 mg fenbendazole orally, along with vitamin E supplements, CBD oil, and bioavailable curcumin. After three months of self-administration, a PET scan revealed no detectable cancer cells in his body. Notably, Tippens was the only patient cured of cancer among the 1,100 clinical trial participants (3). While the Joe Tippens case is compelling, it remains an anecdotal report. It underscores the need for rigorous clinical trials to validate the efficacy and safety of fenbendazole as an anti-cancer therapy.

The anti-cancer activity of fenbendazole has been studied across many cell lines, demonstrating anti-tumor effects against multiple cancer types (Table I) (4-7). Additionally, fenbendazole has shown efficacy against 5-FU, paclitaxel, and docetaxel-resistant cancer cells (5, 8, 9). Compared to albendazole, fenbendazole was more effective against 5-FU-resistant colorectal cells, likely due to its intervention in glycolysis (5).

Ref: Oral Fenbendazole for Cancer Therapy in Humans and Animals