Doctors continue debate over ivermectin for COVID-19

Doctors on Friday continued to debate the merits of ivermectin in a fireside chat organized by the Philippine-American Academy of Science and Engineering.

During the Zoom session, Dr. Tess Lawrie of The Evidence-Based Medicine Consultancy Ltd. presented her analysis of studies that looked into the use of ivermectin as a COVID-19 treatment. Citing her meta-analysis, there were few serious adverse events (SAEs) recorded during ivermectin use during these studies.

Citing data from VigiAccess, an international database of adverse events, Lawrie noted that only 16 deaths have been reported involving ivermectin, compared to much higher totals for remdesivir, which is used to treat COVID-19 symptoms, as well as COVID-19 vaccines.

Lawrie said there is a "double standard" for why ivermectin is being considered unsafe as a COVID-19 treatment. "It doesn't make any sense at all."

Reacting to Lawrie's presentation, Dr. Jacinto Blas Mantaring III, who chairs the Department of Clinical Epidemiology of the University of the Philippines College of Medicine, explained the use of systematic reviews and meta-analyses in research. He proceeded to demonstrate a meta-analysis from covid-nma.com, an international research initiative a living systematic review of COVID-19 trials.

Searching the website for ivermectin studies, Mantaring filtered the results for comparisons against placebo, which showed the relative risk for the drug. "There's a chance that ivermectin causes harm as much as there's a chance that it causes benefit," he said.

Infectious diseases expert Dr. Benjamin Co, for his part, questioned the lack of Phase 2 studies on the appropriate dose of ivermectin, either to be given for patients who are being treated for COVID-19 or its use as prophylaxis.

Lawrie, in response, suggested that the Philippines do a study on the efficacy of ivermectin as prophylaxis for health workers, given the slow rollout of the COVID-19 vaccine in the country. "By doing that, you provide an answer to this very important question," she said.

Lawrie also cited "clinical evidence worldwide" that ivermectin works.

"I think what you have to remember is we are in a pandemic, there are people dying. We don’t need to know about every single thing about this medicine," she said, noting that with more use comes more information.

"We can see it reduces inflammatory markers and this is one of its great benefits in the late stage of disease. So i just think just look at the science. It’s very safe. Let’s just start using it at least for treatment."

Anti-parasitic

Dr. Vicente Y. Belizario Jr., current Dean of the University of the Philippines (UP) College of Public Health, meanwhile, presented the current use cases and discussed the risk profile of ivermectin as an anti-parasitic. He noted that for this purpose, ivermectin's benefits far outweighed its risks.

He also noted that studies on ivermectin's use as a COVID-19 treatment required higher doses of the drug compared to its use as an anti-parasitic.

Belizario then presented adverse effects that have been documented for ivermectin as an anti-parasitic, including toxicity that has led to neurologic impairment and toxic epidermal necrolysis during its use against scabies. "Things like this might happen with more and more use of ivermectin for COVID-19 with higher doses," he said.

He noted that there remains limited data from the clinical trials on the efficacy and safety of ivermectin, adding there needs to be a consensus among doctors, as well as agencies such as the World Health Organization and the country's Food and Drug Administration, for its possible use against COVID-19.

Dr. Rafael Castillo, for his part, argued for "pragmatism" for the use of ivermectin, which he said has "no significant signal for harm" while showing tremendous potential. "I think that's the beauty of pragmatism combined with evidence-based medicine."

Dr. Benigno Agbayani, for his part, argued the need for an emergency use authorization (EUA) for the drug as a treatment for COVID-19 for more widespread use.

The WHO, the US FDA, and the European Medicine Agency currently discourage the use of ivermectin as a COVID-19 treatment except in the context of a clinical trial.

Compassionate use

The Philippines' FDA on Friday granted a hospital’s application for "compassionate use" of ivermectin on humans with COVID-19.

But widespread distribution of ivermectin as part of treatment for COVID-19 is still prohibited, FDA director Eric Domingo said.

He said only the hospital that has the permit for ivermectin’s compassionate use for humans will be allowed to import the drug through a licensed importer.

The FDA chief had earlier clarified that such a compassionate use permit is different from the pending application of two local manufacturers seeking a certificate of product registration for ivermectin.

A compassionate use permit only allows legal administration of the drug in the country but is not an endorsement of its safety and efficacy from the FDA.

A certificate of product registration, on the other hand, will allow manufacturers to sell the drug commercially and is an FDA guarantee that the drug is safe and effective. — JST, GMA News