Ivermectin is an established anti-parasitic medication, approved by the U.S. Food and Drug Administration (FDA) for treating specific infections in humans and animals, such as river blindness and scabies. For their discovery of ivermectin and its effectiveness against parasitic diseases, Satoshi Ōmura and William C. Campbell were awarded the 2015 Nobel Prize in Physiology or Medicine. Beyond these approved applications, ivermectin has captured the attention of scientists and the public for its potential effects on cancer cells.
The Origins of Ivermectin as a Potential Cancer Therapy
The investigation into ivermectin as a cancer therapy originated from a strategy known as “drug repurposing,” which explores new uses for existing, approved medications. This approach can accelerate drug development because repurposed drugs often have well-documented safety profiles from their initial use. For ivermectin, the journey began when initial laboratory observations revealed it had unexpected effects on cancer cells in controlled settings, initiating a dedicated line of research.
This scientific interest was not isolated; researchers have explored repurposing various medications, including those for parasites, high cholesterol, and diabetes, for potential anti-cancer properties. The initial observations with ivermectin warranted further study, focusing on its ability to selectively inhibit the growth of tumor cells at concentrations that were not toxic to normal cells in a lab environment. This selective action suggested that ivermectin might have a mechanism worth investigating for its potential application in oncology.
Pre-Clinical Research Findings
Pre-clinical research involves studies conducted in a laboratory setting, using cancer cells grown in dishes (in vitro) or in animal models (in vivo), and does not involve human subjects. This stage of research is important for understanding a drug’s potential biological activity before it can be considered for human trials. For ivermectin, these pre-clinical studies have explored several ways it might interfere with cancer cells. The findings are confined to laboratory and animal models, and these results do not necessarily translate to effectiveness in humans.
One of the primary mechanisms observed in lab studies is ivermectin’s ability to induce apoptosis, or programmed cell death. In a healthy body, apoptosis is a natural way to remove old or damaged cells. Studies have shown that ivermectin can trigger this process in various cancer cell lines, including breast, colon, and ovarian cancers, by causing mitochondrial dysfunction. It appears to do this by increasing the release of a protein called cytochrome C from the mitochondria, a key step in initiating apoptosis.
Another area of investigation is autophagy, a cellular recycling process where cells degrade and reuse their own components to survive under stress. Ivermectin has been shown to influence autophagy in cancer cells, though its role can be complex. In some cancer cell lines, such as breast cancer, inducing autophagy appears to contribute to cell death. However, in other contexts, like certain melanoma cells, autophagy has been observed to have a protective effect, helping cancer cells survive the stress induced by the drug.
Researchers have also identified that ivermectin can inhibit the proliferation and spread of cancer cells by interfering with specific signaling pathways. One such target is a protein kinase known as PAK1, which is involved in the growth and migration of cancer cells. By inhibiting PAK1, ivermectin has been shown in lab models of breast, ovarian, and brain cancers to slow down tumor cell growth. Studies have also suggested that ivermectin can affect other pathways involved in tumor development.
Human Clinical Trials and Case Studies
The transition from pre-clinical laboratory research to studies in humans represents a major step in evaluating any potential new treatment. It is important to distinguish between anecdotal case studies, reports on one or a few patients, and structured clinical trials. Clinical trials are formal research studies with control groups and specific endpoints to assess a treatment’s safety and effectiveness.
Currently, the evidence for ivermectin’s use in cancer treatment in humans is limited, with the bulk of formal research in its early stages. A few registered clinical trials are underway to investigate ivermectin, usually in combination with other established cancer therapies. For example, a Phase I/II clinical trial is evaluating ivermectin combined with an immunotherapy drug for patients with metastatic triple-negative breast cancer. This type of cancer is considered a “cold” tumor because it has few immune cells, and the study aims to see if ivermectin can make the tumor “hot” by attracting T-cells, thereby enhancing the immunotherapy.
Another Phase II trial is examining the side effects and optimal dose of ivermectin when given with an immunotherapy drug to patients with the same type of metastatic breast cancer. The primary goals of these early-phase trials are to determine a safe dosage, monitor for side effects, and get a preliminary sense of whether the treatment combination can shrink tumors. These studies are not designed to prove that ivermectin cures cancer but to assess its potential role as part of a combination therapy. The results from these trials are not yet available, as the studies are estimated to be completed in the coming years.
Official Stance and Safety Considerations
Major regulatory and health organizations, including the U.S. Food and Drug Administration (FDA) and the National Cancer Institute (NCI), have clear positions on the use of ivermectin for cancer. Based on the current scientific evidence, neither the FDA nor the NCI has approved or recommended ivermectin as a treatment for any type of cancer. The NCI has stated that it does not have information from its resources to support the claim that ivermectin is a cure for cancer. The FDA cautions against its use for unapproved indications.
Using any drug off-label, particularly at doses higher than those approved, carries risks. The FDA has warned that ivermectin can interact with other medications, such as blood thinners, and an overdose can lead to serious health consequences, including seizures, coma, and even death. Some pre-clinical studies have used ivermectin concentrations that would require extremely high doses in humans, which could lead to severe neurological side effects.
Pursuing unproven therapies can also lead patients to delay or forgo standard-of-care treatments that have been tested and shown to be effective. This can have dangerous consequences, potentially leading to worse outcomes. Therefore, anyone considering cancer treatment must consult with a qualified oncologist, as decisions about care should be based on proven therapies and professional medical guidance.