Merck, FDA Caution Against Using Ivermectin as a COVID-19 Treatment

Merck’s anti-parasitic drug Stromectol (ivermectin) is being studied in multiple clinical trials as a potential COVID-19 treatment, but — at least for now — the company is warning against its use.

Used to treat roundworms, threadworms and other parasites in both humans and animals, ivermectin is also an antiviral that has been shown in in vitro studies to inhibit the coronavirus that causes COVID-19.

At least five clinical trials of ivermectin, including as a possible nasal spray, an inhaled powder or in an impregnated mask are planned or under way, according to the National Institutes of Health.

And the drug has a solid track record of safety. Since 1987, Merck has donated ivermectin to the World Health Organization for prevention of an inflammatory condition linked to a parasitic worm (Onchocerca volvulus) that causes intense skin itching and eventual blindness.

But ivermectin has not been included the UK’s multi-arm RECOVERY trial that is evaluating potential COVID-19 treatments — from the commonly used anti-inflammatory colchicine to Regeneron’s monoclonal antibody cocktail to Eli Lilly’s rheumatoid arthritis drug Olumiant (baricitinib), to aspirin.

Merck said that while its scientists are continuing to evaluate the drug’s safety and efficacy for COVID-19 patients, so far there is “no scientific basis for a potential therapeutic effect against COVID-19 from pre-clinical studies; no meaningful evidence for clinical activity or clinical efficacy in patients with COVID-19 disease; and a concerning lack of safety data in the majority of studies.”

“We do not believe that the data available support the safety and efficacy of ivermectin beyond the doses and populations indicated in the regulatory agency-approved prescribing information,” Merck said.

Similarly, the FDA posted a document online in mid-December stressing that ivermectin “is not approved for the prevention or treatment of COVID-19,” and that “additional testing is needed to determine whether ivermectin might be appropriate to prevent or treat coronavirus or COVID-19.” — Martin Berman-Gorvine