Ivermectin: Uses, Evidence & Current Research for Cancer & More

The story of ivermectin is a complex one, marked by both legitimate medical breakthroughs and a surge of misinformation. Originally hailed as a revolutionary treatment for parasitic diseases, the drug gained notoriety during the COVID-19 pandemic due to unsubstantiated claims of its efficacy against the virus. Now, researchers are exploring its potential as a cancer treatment, initiating early human clinical studies. But what does the evidence actually reveal about what ivermectin can effectively treat?

A History of Discovery and Debate

Ivermectin is a modest organic chemical derived from the bacterium Streptomyces avermitilis, first discovered in soil samples near a Japanese golf course. Its development represented a significant advancement in treating parasitic infections in both humans and animals. The drug’s impact was recognized with the 2015 Nobel Prize in Physiology or Medicine, awarded to its discoverers. Approved for veterinary use in 1981 and human use in 1987, ivermectin is currently available in tablet and cream formulations. Tablets and creams are available by prescription.

However, ivermectin’s journey hasn’t been without controversy. During the early stages of the COVID-19 pandemic, the drug was widely promoted on social media as a “miracle cure,” despite a lack of robust scientific evidence. This led to widespread misuse and, in some cases, serious health consequences. Now, the United States National Cancer Institute is investigating its potential in cancer treatment, with initial human trials underway.

Evaluating the Evidence: Cochrane Reviews as a Gold Standard

Determining the true efficacy of any medication requires rigorous evaluation through human clinical trials. However, the most reliable summaries of evidence come from Cochrane reviews. These reviews, conducted by panels of experts, systematically collate and assess all relevant data from multiple clinical trials and studies, employing strict methodologies to minimize bias and identify flawed research. Cochrane reviews are regularly updated to incorporate new findings, providing the highest level of evidence for informed decision-making. They are considered the gold standard in evidence-based medicine.

What Does the Evidence Say?

Gut and Lymphatic Worms: A Proven Benefit

Ivermectin remains a highly effective treatment for several parasitic worm infections, including roundworms like Ascaris lumbricoides and Strongyloides stercoralis, as well as worms causing lymphatic filariasis (elephantiasis). For Strongyloides stercoralis, Cochrane reviews indicate ivermectin is superior to albendazole and has fewer side effects than thiabendazole. The evidence supports its use. For Ascaris lumbricoides, ivermectin performs comparably to albendazole and mebendazole. The Cochrane panel concluded that it was as good as these other treatments. In treating lymphatic filariasis, ivermectin, combined with albendazole, is recommended as standard treatment. Cochrane reviews support this combination.

Rosacea: Some Improvement

A Cochrane review evaluating 22 treatments for rosacea found that ivermectin applied to the skin was more effective than a placebo and slightly better than metronidazole, a common topical medication. This suggests a potential benefit for managing this skin condition.

Scabies: Comparable to Permethrin

Cochrane reviews on scabies treatment show mixed results. One review found ivermectin and permethrin to be equally effective, regardless of administration method. However, another review suggested that topical permethrin may be the most effective treatment overall. The evidence is nuanced, and permethrin remains a common first-line treatment. Further research is needed to clarify the optimal approach.

Malaria: Insufficient Evidence

A Cochrane review examining ivermectin’s potential to reduce malaria transmission found insufficient evidence to draw firm conclusions. A single clinical trial, with a high risk of bias, showed no clear effect. The panel could not determine whether ivermectin had any impact on infection rates.

River Blindness: Uncertain

Evidence regarding ivermectin’s effectiveness in preventing visual impairment and blindness caused by river blindness (onchocerciasis) is limited. A Cochrane review of four clinical trials and two community-based studies found insufficient data to make a definitive recommendation. The panel suggested that the drug’s effectiveness may vary depending on the parasite strain and the patient’s ethnicity.

Cancer: Early Stage Research

Currently, there are no Cochrane reviews on ivermectin’s use for cancer, as clinical interest in this area is relatively new. A clinical trial is underway evaluating ivermectin in combination with antibody-based drugs for breast cancer. Preliminary results indicate the combination is safe for patients, but efficacy data has not yet been published. More research is needed to determine its potential role in cancer treatment.

COVID-19: No Evidence of Benefit

The Cochrane review on ivermectin for COVID-19 concluded that there is no evidence to support its use for either treatment or prevention. The review rigorously assessed data from multiple clinical trials and rejected trials with significant methodological flaws, including those comparing ivermectin to ineffective treatments like hydroxychloroquine.

The story of ivermectin serves as a powerful reminder of the importance of relying on robust scientific evidence and the dangers of misinformation. While the drug holds proven benefits for certain parasitic infections, its use for other conditions, including COVID-19, remains unsupported by evidence. Ongoing research into its potential as a cancer treatment offers a glimmer of hope, but further investigation is crucial to determine its true efficacy and safety.