Some studies already have been done on hydroxychloroquine and the closely related chloroquine, including one published on Friday showing a higher risk of death and heart rhythm problems for coronavirus patients who used them compared to those who did not. But doctors are waiting for the debate about the usefulness of these drugs for COVID-19 to be settled by gold-standard scientific trials, with some results due as soon as next week.
Such research involves randomized trials comparing these drugs to a placebo, with neither doctors nor patients aware of who gets what.
In laboratory experiments, hydroxychloroquine and chloroquine both inhibited the novel coronavirus. Doctors around the world began giving hydroxychloroquine, the less toxic of the pair, to patients. Early reports have been largely disappointing.
Hydroxychloroquine, for example, failed to reduce the need for breathing tubes or risk of dying in critically ill patients with COVID-19, the respiratory disease caused by the virus, at Columbia University.
The study published in The Lancet involved nearly 96,000 hospitalized patients, including 15,000 treated with hydroxychloroquine or chloroquine. It was not a randomized trial but rather a retrospective analysis of medical records that can show correlation rather than causation.
The U.S. Food and Drug Administration last month warned against using hydroxychloroquine, first approved in 1955, outside of clinical trials due to risks of dangerous irregular heartbeats.
Worldwide, many gold-standard trials are underway. They explore whether hydroxychloroquine can prevent or treat COVID-19, which patients might benefit, when treatment might start, how long it might continue and what dose might be best.
The University of Minnesota may have some results next week. It is testing whether hydroxychloroquine prevents infection in people exposed to the coronavirus and whether it alleviates COVID-19 symptoms. Other placebo-controlled trial results are expected starting this summer.
Most hydroxychloroquine trials thus far have involved hospitalized patients, but “any potential benefit or activity of these agents ... would likely be best observed earlier in the disease course,” said UCLA Medical Center infectious disease specialist Dr. Kara Chew. “Once people are hospitalized, they are quite sick.”
Several trials are targeting early stages of COVID-19, including a U.S. National Institutes of Health study announced last week, co-chaired by Chew, and another sponsored by the Bill and Melinda Gates Foundation trial.
A U.S. National Heart, Lung and Blood Institute trial involving 510 hospitalized COVID-19 patients is testing whether 15 days of hydroxychloroquine is more helpful than placebo. A global prevention trial with sponsors including Wellcome and the Gates Foundation is having 40,000 health workers take the pills for three months.
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