Fenbendazole and Cancer
There is an increasing trend of using Fenbendazole as a complementary therapy in treating cancer. This blog post explores the mechanism of action, evidence and whether there is any legitimacy to its use.
What is Fenbendazole?
Fenbendazole was traditionally developed as a dog dewormer. It has anti-parasitic activity with high efficacy and very low toxicity in both animals and humans when used for this purpose. The only reported side effects when used in this fashion are vomiting and diarrhoea. Its main metabolism is through the liver and it is excreted mostly in the faeces with very little found in urine.
Mechanism of Action?
Fenbendazole acts on tubulin to disrupt its function within microtubules. Correct tubulin function is important for cell proliferation, motility, division, intercellular transport of organelles, maintenance of cell shape and the secretion process of cells in all living organisms. By doing this, glucose uptake is disrupted draining energy stores. Its use therefore in parasites blocks their capacity to divide, proliferate or survive.
Because microtubules are such key components in cell functioning in cancer cells, disrupting them poses a great threat to the survival of cancer cells. This is not a new concept as microtubules have been the targets for two classes of chemotherapeutic agents to date and are still in common use.
What is the Evidence?
The discovery of the toxicity to cancer cells was found incidentally during in vitro cell line studies of cancer cells that failed to grow when exposed to fenbendazole which was being used for other purposes in the lab. This led to more deliberate mouse models that showed fenbendazole to slow tumour cell growth.
Its use was made popular when Joe Tippens began sharing his story of treating small cell lung cancer using this agent partnered with three other naturopathic supplements (namely vitamin E, curcumin and CBD).
There have been no large-scale clinical trials or formally published case studies in peer-reviewed scientific journals. There are a number of anecdotal stories being shared on social media platforms, however, there are may agents often being used in these scenarios so it is difficult to isolate this alone as the effective agent.
There is one case report describing a case of liver injury, however, the patient was also on pembrolizumab immunotherapy which has a known and well documented risk of hepatitis. The liver injury appeared to reverse on cessation of fenbendazole but it appears that pembrolizumab was ceased at a similar time.
What Do We Conclude?
More formal data is required if we are to explore the validity of the effectiveness of fenbendazole against cancer. In clinical circumstances where there is little to lose, one must be compassionate about the personal choices made and because of the risk to the liver, I highly recommend working with a professional with experience in this area before embarking on a journey of using this without guidance and supervision.
References
1. Park D, Lee JH, Yoon SP. Anti-cancer effects of fenbendazole on 5-fluorouracil-resistant colorectal cancer cells. Korean J Physiol Pharmacol. 2022 Sep 1;26(5):377-387. doi: 10.4196/kjpp.2022.26.5.377. PMID: 36039738; PMCID: PMC9437363.
2. Dogra N, Kumar A, Mukhopadhyay T. Fenbendazole acts as a moderate microtubule destabilizing agent and causes cancer cell death by modulating multiple cellular pathways. Sci Rep. 2018 Aug 9;8(1):11926. doi: 10.1038/s41598-018-30158-6. PMID: 30093705; PMCID: PMC6085345.
3. Duan Q, Liu Y, Rockwell S. Fenbendazole as a potential anticancer drug. Anticancer Res. 2013 Feb;33(2):355-62. PMID: 23393324; PMCID: PMC3580766.
4. Cray C, Altman NH. An Update on the Biologic Effects of Fenbendazole. Comp Med. 2022 Aug 1;72(4):215-219. doi: 10.30802/AALAS-CM-22-000006. Epub 2022 Jun 28. PMID: 35764389; PMCID: PMC9413524.
5. Gao P, Dang CV, Watson J. Unexpected antitumorigenic effect of fenbendazole when combined with supplementary vitamins. J Am Assoc Lab Anim Sci. 2008 Nov;47(6):37-40. PMID: 19049251; PMCID: PMC2687140.
6. Chang CS, Ryu JY, Choi JK, Cho YJ, Choi JJ, Hwang JR, Choi JY, Noh JJ, Lee CM, Won JE, Han HD, Lee JW. Anti-cancer effect of fenbendazole-incorporated PLGA nanoparticles in ovarian cancer. J Gynecol Oncol. 2023 Sep;34(5):e58. doi: 10.3802/jgo.2023.34.e58. Epub 2023 Apr 24. PMID: 37170725; PMCID: PMC10482585.
7. Sultana T, Jan U, Lee H, Lee H, Lee JI. Exceptional Repositioning of Dog Dewormer: Fenbendazole Fever. Curr Issues Mol Biol. 2022 Oct 17;44(10):4977-4986. doi: 10.3390/cimb44100338. PMID: 36286053; PMCID: PMC9600184.
8. Yamaguchi T, Shimizu J, Oya Y, Horio Y, Hida T. Drug-Induced Liver Injury in a Patient with Nonsmall Cell Lung Cancer after the Self-Administration of Fenbendazole Based on Social Media Information. Case Rep Oncol. 2021 Jun 17;14(2):886-891. doi: 10.1159/000516276. PMID: 34248555; PMCID: PMC8255718.
9. https://www.fenbendazoleaustralia.com.au/
