Fenben lab fenbendazole is an antihelminthic medication that is also widely used as a parasiticide. Its cytotoxic effects in animals and in human cancer cell lines have suggested that it could be a useful cancer treatment. It has been repurposed from its anthelmintic use and is currently being studied in human trials. However, it will be a long road from the laboratory to the pharmacy.
We report on the first case of a patient with advanced non-small-cell lung cancer who experienced a significant tumor shrinkage after self-administering oral fenbendazole (FZ). The patient was taking pembrolizumab monotherapy at the time of her symptom onset. Her CEA levels had increased, and she feared progression of her cancer. The patient reported that she had started taking FZ on her own based on information she found on social media sites that stated this drug was effective against cancer.
The anthelmintic FZ is thought to act by binding to and disrupting the function of microtubules. It is also known to block cell-cycle progression by inhibiting the formation of mitotic spindles and inducing mitotic catastrophe. To explore the potential of using fenbendazole as an anticancer agent in combination with radiation and/or chemotherapy, we tested its effects on EMT6 cells in vitro and as solid tumors in mice. Febendazole alone and in maximally-intensive regimens produced cytotoxic effects on the tumor cells and significantly reduced their ability to grow. Febendazole did not alter the dose-response curve for radiation or docetaxel and did not increase the antineoplastic effects of these drugs.