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  • Writer's pictureJake Psenka

Fenbendazole and the Azoles Part 2

Updated: Sep 21, 2023

In 2019 people began taking a veterinary medicine known as fenbendazole to treat cancer. At that time, this was a new off-label use of the drug and several people told me about a man who had cured his cancer this way. Intrigued, I looked into it and what I found surprised me. I learned that researchers had been studying fenbendazole’s cancer fighting activity since at least 2005. It turns out that sometime around 2005 a lab found it impossible to implant cancer cells onto laboratory animals. After analyzing the situation, it was determined that the animals had been treated with fenbendazole to eliminate parasites, and in doing so had made them resistant to cancer cells. At that time I wrote an article about the research regarding fenbendazole and cancer- you can read it here.

More recently, several papers were published describing the anticancer action of fenbendazole and it’s human-use equivalent, mebendazole. Turns out that fenbendazole and mebendazole and the other -azole drugs work similarly to one the most powerful types of chemotherapy drugs, the taxanes.

The taxanes inhibit cancer cell replication by interfering with DNA replication. Azole drugs exhibit this activity as well, but without the toxicity. Additionally, the –azole drugs can also upregulate a specific gene called the p53 gene that is responsible for inhibiting the growth and development of melanoma and breast cancer cells. Studies also showed promise in fighting other types of cancer cells as well such glioblastoma multiforme, prostate cancer, and lymphoma.

The most exciting research I found back in 2019 regarding the –azole drugs involved a specific type of lung cancer known as KRAS mutated non-small cancer lung cancer (NSCLC). Mutation of the KRAS gene promoted a more aggressive form of lung cancer. About 30% of NSCLC’s have this mutation of KRAS and there are few, if any, reliable treatments for these cancers. The study published by the National Cancer Institute of Japan concluded that “benzimidazole derivatives play an important role in suppressing KRAS-mutant lung cancer cells.”

Since 2019 several more articles of medical research have been published regarding fenbendazole and mebendazole. A study from January 2021 reported that mebendazole inhibited the growth of ovarian cancer cells in both cell cultures as well as in laboratory animals implanted with human cancer cells. An additional study from July 2021 reported that mebendazole could re-sensitize chemotherapy resistant ovarian cancer cells to treatment. Both of these studies suggested that mebendazole should receive continued study to further characterize it’s possible use in ovarian cancer. New and innovative treatments for ovarian cancer are desperately needed as over 70% of patients with this type of cancer have recurrences.

Another particular study that caught my eye involved an –azole drug called flubendazole and castration resistant prostate cancer. The drug was found to suppress cancer cell growth and to synergize with conventional treatment of this difficult to treat prostate cancer. Flubendazole has also shown some very promising results with melanoma as well.

Prior to fenbendazole’s internet notoriety in 2019 I was aware of the –azole drugs potential as a repurposed oncology medication. In 2017 a paper was published that reported on mebendazole’s use as an alternative to the chemotherapy drug vincristine in treating brain tumors. Vincristine, like the taxane drugs, is a microtubule inhibitor and is used to treat brain tumors such as glioblastomas and medulloblastomas. Unfortunately, vincristine does not penetrate well into brain tissue, which limits its therapeutic potential. This study reported that mebendazole was better than vincristine at penetrating brain tissue and had a favorable safety profile. Further, the authors confirmed that mebendazole’s mechanism of action against brain tumors was via microtubule inhibition, and its use resulted in improved survival times in orthotopic tumor models compared to vincristine. The paper concluded with the strong recommendation that mebendazole be used as a replacement for vincristine in the treatment of brain tumors.

This idea of using a drug for purposes other than it’s intended use is called “drug repurposing,” and is currently a very popular subject in the integrative oncology field. Several well-known and inexpensive medications have been shown to have significant anti-cancer effects. These include the blood sugar medication metformin, the cholesterol drug Lipitor, the anti-inflammatory drug Celebrex, the anti-malarial medication artesunate, and even aspirin. Additionally, the safety profile of these medications are well-known as they are given to millions of people annually. Repurposed medications, in addition to having some significant anti-tumor activity, have demonstrated synergistic activity with many conventional therapies.

In my office we are currently utilizing new blood-based testing to help guide re-purposed medication recommendations. This technology allows us to collect a sample of a cancer’s genetic material via a blood draw. This genetic material is then analyzed to determine what treatments the cancer could be susceptible to.

With the current research regarding the benefits of combining integrative medicine, along with selected re-purposed medications we are more capable of successfully fighting cancer than ever.



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