The first substantial peer-reviewed clinical trial of the drug against Covid-19 finds no evidence that it is a wonder medicine
- A study in Columbia of 398 people with mild Covid-19 symptoms found that ivermectin offered no statistically significant benefit over placebo.
- This is the first peer-reviewed large clinical trial of the drug against Covid-19 in a prestigious medical journal.
- It comes against the background of four court cases that have been launched against South Africa's medicines' regulator to compel it to make ivermectin available for the treatment of Covid-19, even though there is no compelling evidence of the drug's benefit.
Four court cases have been launched against the South African Health Products Regulatory Authority (SAHPRA) to compel the regulator to make ivermectin available for the treatment of Covid-19. Among the applicants are Afriforum and the ACDP. Yet not a single peer-reviewed clinical trial in a leading medical journal has shown that ivermectin is effective against coronaviruses.
Ivermectin is an anti-parasitic drug, used to treat river blindness (a disease caused by a parasite). The only ivermectin products approved by SAHPRA are for veterinary use.
Now the results of a trial published in the prestigious Journal of American Medical Association (JAMA) should strengthen SAHPRA's arm in its legal battles. Among 398 adults with mild Covid-19, a five-day course of ivermectin compared with a placebo, did not significantly improve symptoms.
This was a double-blind, randomized trial. In other words, neither the participants nor the researchers knew who was receiving ivermectin or a placebo until the trial was finished. It is the first such study with published peer-reviewed results. (A trial with inconclusive results was published in The Lancet a few weeks ago but it only had 24 participants.)
The findings don't support the use of ivermectin for treatment of mild Covid-19, although larger trials may be needed to understand the effects of ivermectin on other clinically relevant outcomes, the researchers concluded.
Adult patients from Cali in Columbia who had mild Covid-19 symptoms for seven days or less, were enrolled into the study between July and November 2020. They were monitored until the middle of December. Patients were excluded if they were asymptomatic, pregnant, breastfeeding, had severe pneumonia, had received ivermectin within the previous five days, or had kidney or liver disease.
A total of 200 patients received ivermectin and 198 received a placebo for five days. The dosage was determined by body weight, 300 μg/kg (microgram/per kilogram). The placebo group was slightly older (eight people over 65 versus four in the ivermectin group) and had more males (89 vs 78).
Andy Gray, senior lecturer in the Division of Division of Pharmacology at University of KwaZulu-Natal, told GroundUp that it should be noted that the cases were all symptomatic, and the endpoint was the time to those symptoms being reported by patients as resolved.
After 21 days 82% of the patients who received ivermectin had no symptoms and 79% of those who received the placebo were symptom free. Average time till symptoms alleviated was ten days in the ivermectin group versus 12 in the placebo one. These results are not statistically significant and could also be a result of the placebo group having more participants over 65 and more males. There were also no significant differences in the medical care the two groups needed, or who needed more serious medical intervention.
The study concluded: "However, the relatively young and healthy study population [average age of 37] rarely developed complications, rendering the study underpowered to detect such effects. Therefore, the ability of ivermectin to prevent the progression of mild Covid-19 to more severe stages would need to be assessed in larger trials."
The authors wrote that ivermectin did not significantly affect the course of Covid-19, and this is consistent with models showing that even at ten times the approved dose the amount of ivermectin is insufficient to make a big enough difference against the virus.
Gray added that one of the key issues with ivermectin has been the lack of clarity about the dose to be used. Doses in various studies have varied from 200‐600 μg/kg, or clinicians have used multiples of the 3mg dosage from 6‐12mg. The dose interval also varies: from a daily dose to once every ten days; so does the duration: from a single day to 10 days.
The dose used in this study is not the highest or the lowest used, but somewhere in the middle, he said.
Gray explained: "The initial [laboratory] work indicated that far higher doses than had previously been used in humans (for other indications) would be needed to reach the concentrations associated with antiviral activity. However, there were also claims of other possible mechanisms of action. The clinical trial does, however, seem to support a lack of a clinically relevant antiviral effect at the dose used, when initiated in mild cases (mostly outside of hospital)."
The researchers noted some limitations of the study such as the young study participants and the results may be different in older people; virological assessments were not included; the placebo used in the first 65 patients differed in taste and smell from ivermectin amongst others.
SAHPRA recently said in a statement: There is an erroneous notion that it "buckled under pressure" as a consequence of the court actions brought against it regarding access to ivermectin. "Saphra wishes to state unequivocally that this is not the case."
The court deliberations culminated in an order that reiterates the position that SAHPRA communicated on 27 of January. In other words, a programme of controlled compassionate use of ivermectin remains in place.
As the court cases proceed there is still no compelling evidence that ivermectin has any efficacy for Covid-19 or any answers to these questions: What dose of ivermectin would be effective? For how many days? And at what stage of Covid-19 disease?