Ivermectin: From Parasite Treatment to Cancer Research – A Comprehensive Look

Ivermectin, a drug initially hailed as a breakthrough in treating parasitic infections, has experienced a tumultuous journey marked by misinformation, debate, and now, renewed scientific interest. Originally celebrated for its effectiveness against parasitic diseases in humans and animals, it gained notoriety during the COVID-19 pandemic due to unsubstantiated claims of its efficacy. Today, the United States National Cancer Institute is investigating its potential as a cancer treatment, initiating early human clinical studies. But what does the science actually say about what ivermectin can treat?

What is Ivermectin?

Ivermectin is a small organic chemical derived from the bacterium Streptomyces avermitilis, found in soil near a Japanese golf course. Its discovery in the 1970s was considered a major advancement, earning its discoverers the 2015 Nobel Prize in Physiology or Medicine . Approved for veterinary use in 1981 and human use in 1987, it is now available in tablet and cream formulations.

Assessing the Evidence: The Role of Cochrane Reviews

Determining the effectiveness of a medication relies on rigorous scientific evaluation. While governments use clinical trials for approval, the highest level of evidence comes from Cochrane Reviews. These reviews, conducted by panels of experts, systematically collate and assess all relevant data on a medication, scrutinizing study designs to minimize bias and provide a comprehensive, regularly updated summary to guide decision-making.

What Does the Evidence Say?

Gut and Lymphatic Worms

Ivermectin is an established treatment for various parasitic worm infections, including roundworms like Ascaris lumbricoides and Strongyloides stercoralis, as well as those causing lymphatic filariasis (elephantiasis). Cochrane reviews indicate ivermectin is superior to albendazole for Strongyloides stercoralis with fewer side effects, and comparable to albendazole and mebendazole for Ascaris lumbricoides. For lymphatic filariasis, ivermectin or diethylcarbamazine, in combination with albendazole, is recommended as standard treatment.

Rosacea

A Cochrane review evaluating 22 treatments for rosacea found that ivermectin applied to the skin was more effective than a placebo and slightly more effective than metronidazole, a standard medication.

Scabies

Cochrane reviews on scabies show mixed results. One review found ivermectin and permethrin equally effective, while another suggests topical permethrin may be the most effective treatment.

Malaria

Evidence regarding ivermectin’s role in malaria transmission is inconclusive. A single clinical trial showed no preventative effect, and due to the trial’s high risk of bias, the Cochrane panel could not draw definitive conclusions.

River Blindness

The Cochrane review on river blindness (caused by Onchocerca volvulus) found insufficient evidence to determine ivermectin’s effectiveness in preventing infection-based visual impairment, and blindness. The panel suggested the drug’s efficacy may vary depending on parasite strain and ethnicity.

Cancer

Currently, there are no Cochrane reviews on ivermectin’s use for cancer, as clinical interest in this area is recent. The United States National Cancer Institute is evaluating ivermectin in combination with antibody-based drugs for breast cancer. Early results indicate the combination is safe, but efficacy data is pending.

COVID-19

A comprehensive Cochrane review, analyzing data from 11 clinical trials, concluded there is no evidence to support the use of ivermectin for the treatment or prevention of COVID-19. The review rejected data from trials comparing ivermectin to ineffective drugs like hydroxychloroquine.

A History of Misinformation

During the COVID-19 pandemic, ivermectin gained unwarranted attention as a potential “miracle cure” fueled by social media claims despite a lack of robust evidence. This led to increased use and, in some cases, harmful consequences. A JAMA study found that 6% of individuals reported using ivermectin or hydroxychloroquine, and those who endorsed COVID-19 vaccine-related misinformation were more likely to do so. The Washington Post reported that medical boards received over 480 complaints related to COVID-19 misinformation, with at least 20 doctors facing repercussions for promoting unproven treatments .

Looking Ahead

Ivermectin’s story is a complex one, highlighting the importance of evidence-based medicine and the dangers of misinformation. While its established role in treating parasitic infections remains, ongoing research into its potential applications, such as in cancer treatment, warrants further investigation. Although, it is crucial to rely on rigorous scientific evidence and consult with healthcare professionals before considering any treatment.