The anthelmintic drug fenbendazole is a common treatment for parasites in animals but has not been shown to cure cancer.
Health Canada lists fenbendazole as being for veterinary use only and the drug is not approved for human use. However, the antiparasitic medication is being investigated as a potential cancer treatment after several videos of unlicensed veterinarians using fenbendazole to treat dogs with stage 4 cancer were posted on TikTok in 2020.
The videos have since been deleted but were viewed millions of times. One video featured Andrew Jones, a vet in British Columbia, who claims that the dog deworming drug has cured his small-cell lung cancer. He also claims that fenbendazole has cured the cancers of his wife and two daughters.
Our in vitro experiments showed that fenbendazole inhibited the proliferation of 5-FU-sensitive and resistant CRC cells at micromolar concentrations. Cells with wild-type p53 were more sensitive to fenbendazole than cells with mutant p53, and fenbendazole induced G2/M phase arrest via p53-p21 pathways in both SNU-C5 and SNU-C5/5-FUR CRC cells. In addition, fenbendazole induces apoptosis in both 5-FU-sensitive and resistant cells by p53-dependent apoptosis and p53-independent ferroptosis-augmented apoptosis (Fig. 8A). The latter was triggered by reduced expression of the autophagy/ferroptosis factor GPX4 and by mitochondrial damage.
In vivo studies of EMT6 tumors in BALB/c mice showed that three daily i.p. injections of fenbendazole significantly decreased the growth of the tumors compared to controls. Tumor growth was rigorously analyzed and time to reach four-times the tumor volume at stratification for each group was calculated. In line with in vitro data, fenbendazole significantly delayed the growth of unirradiated and irradiated tumors in vivo, but not untreated or treated controls.fenbendazole stage 4 cancer