The World Health Organization has halted research on whether hydroxychloroquine could be an effective treatment for COVID-19.
Multiple studies have shown that the drug, an anti-malarial medicine also used to treat lupus and rheumatoid arthritis, has no impact on the coronavirus.
The WHO said in a statement Wednesday that recent findings "showed that hydroxychloroquine does not result in the reduction of mortality of hospitalized COVID-19 patients."
The decision will not affect other research examining whether hydroxychloroquine might be beneficial to prevent COVID-19 or for patients after they recover from the virus.
So far, only one drug, remdesivir, has been shown in clinical trials to help very sick patients in the hospital recover faster. And Tuesday, researchers at the University of Oxford in England reported that a commonly used steroid called dexamethasone can help COVID-19 patients on ventilators survive the illness, although the data from that trial have not be made public.
Hydroxychloroquine gained attention as a potential COVID-19 treatment in February, when small studies suggested it might be useful against the virus. But subsequent research concluded that it was not beneficial.
What's more, hydroxychloroquine is known to cause side effects, including abnormal heart rhythm, in some people.
But enthusiasm for the drug continued because President Donald Trump encouraged its use, even saying in May that he had taken it to prevent COVID-19, despite no evidence that it would work. A study published in early June found that hydroxychloroquine was no better than a placebo at preventing coronavirus infection.
"The combined evidence from these large, randomized trials suggests that hydroxychloroquine, when compared with the standard of care in the treatment of hospitalized COVID patients, does not result in the reduction of mortality of those patients," Dr. Ana Maria Henao-Restrepo, a medical officer with the WHO's department of immunization, vaccines and biologicals, said at a news briefing Wednesday.
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Henao-Restrepo emphasized that stopping the hydroxychloroquine trial did not reflect any specific WHO policy.
On Monday, the Food and Drug Administration rescinded its emergency use authorization for hydroxychloroquine to treat hospitalized COVID-19 patients, saying the drug carries too many risks without any apparent benefit.