A benzimidazole anthelmintic, fenbendazole is widely used for the treatment of parasitic diseases. It also has cytotoxic and cytostatic properties in cancer cells. In 2018, a researcher from Johns Hopkins Medicine reported that high concentrations of the drug could inhibit the growth of paclitaxel-resistant tumors in culture.[1] In 2021, a press release from the same institution described that fenbendazole and two other drugs from the same class—albendazole and mebendazole—were able to slow down pancreatic tumor growth in mice.
The authors studied the effect of fenbendazole on tumor growth and radiation response in EMT6-bearing mice. Tumor volumes and lung metastases were assessed on necropsy after the animals were euthanized. Mice were randomized to receive fenbendazole (as indicated by the three dark arrows in the graph) or placebo, and then were subjected to local tumor irradiation. No differences in either tumor size or lung metastases were observed between untreated and fenbendazole-treated mice.
Febendazole is known to interfere with microtubule dynamics in mammalian cells, a mechanism that blocks important cell processes. This activity is believed to contribute to its cytostatic and cytotoxic effects. The authors found that 2-h treatments of EMT6 cells with fenbendazole did not change their viability in a colony formation assay, but 24-h incubations led to a marked reduction in the number of colonies formed and in the clonogenicity of these cells. Severe hypoxia increased the toxicity of these treatments. However, fenbendazole did not alter the radiation dose-response curves of aerobic or hypoxic EMT6 cells, and did not synergistically increase the antineoplastic activity of docetaxel in these conditions.fenbendazole for cancer