Fenben lab fenbendazol is an antiparasitic medication that can be given orally to dogs, cats and other mammals. It is part of a group of drugs called benzimidazole carbamates, which have been in wide use as anthelmintics for decades. The benzimidazole carbamates work by binding to the b-tubulin microtubule subunits and disrupting their polymerization. It has been recently reported that fenbendazole and other members of this class also have antitumor activities in human cancer cells via this mechanism.
The fenben lab fenbendazol (methyl N-(6-phenylsulfanyl-1H-benzimidazol-2-yl) carbamate) is a broad-spectrum benzimidazole anthelmintic that has been used to treat common helminth infections in numerous animal species. It has an excellent safety margin and is generally well tolerated by most animals. It has also been found to have potent anti-cancer activity in laboratory experiments. Repurposing veterinary drugs that show promise as potential cancer treatments may help shorten the time and costs involved in developing new drugs.
Recently, it has been shown that fenbendazole also inhibits cell cycle progression by binding to and destabilizing cyclin B1-CDK1. Cyclin B1 is a regulator of the G2 checkpoint that controls mitosis. Destabilization of cyclin B1-CDK1 inhibits progression through mitosis, thus preventing cell division. This effect was demonstrated using human cancer cells that were synchronized by serum starvation and then treated with varying doses of fenbendazole. The effects of fenbendazole on cell-cycle progression were evaluated by measuring the kinetics of anaphase-promoting complex (APC) activity, mitotic catastrophe and cell viability.
These results indicate that fenbendazole has significant antitumor activity in human cancer cells, similar to methiazole. However, in contrast to methiazole, fenbendazole does not inhibit cell cycle progression at higher concentrations. Whether or not this difference is clinically relevant remains to be determined.
In vivo studies of fenbendazole’s antitumor activities have been conducted using several different animal models, including xenografts in mice and in situ carcinomas in rats. In a study in which human lung cancer cells were transplanted into athymic nu/nu mice and treated with 1 mg/mouse of fenbendazole every other day for 30 days, the tumors rapidly shrank and were eventually eradicated in 80% to 100% of the animals studied.
In addition, fenbendazole was able to shrink human prostate and breast cancer tumors in rats by targeting the same mechanisms in these animals that it targets in mammalian cells. Furthermore, fenbendazole showed potent and consistent antitumor activity in rat models of metastatic colon cancer and mesothelioma.
It is important to note that fenbendazole must be administered for a full course of treatment in order to kill parasites. It should not be given to pets that are actively growing feathers or during molting, as the drug may affect the development of these feathers. It is also important to monitor a pet’s condition while on fenbendazole to make sure that it does not cause adverse reactions, such as facial swelling, hives, diarrhea or shock. If an allergic reaction occurs, seek veterinary care immediately. At regular doses, fenbendazole is usually well tolerated by most animals.