On Monday, the United States withdrew President Donald Trump's anti-malarial medications for the treatment of the new corona virus for emergencies, closing the door to politically charged treatments.
Hydroxychloroquine (HCQ) and chloroquine (CQ) were approved in March after they were found to inactivate the virus in test tubes, and early small studies showed that they also worked well in humans.
Since then, however, larger, more controlled experiments have shown that the two drugs are ineffective in treating COVID-19 or preventing infection in people who have been exposed to the virus.
In the meantime, safety concerns have been raised regarding their use – especially the risk of causing irregular heartbeat in certain patients.
"It is no longer reasonable to believe that oral formulations of HCQ and CQ can be effective in treating COVID-19," Denise Hinton, chief scientist at the Food and Drug Administration (FDA), wrote in a letter.
"Nor is it reasonable to believe that the known and potential benefits of these products outweigh the known and potential risks.
"Accordingly, the FDA is revoking the EUA for the emergency use of HCQ and CQ to treat COVID-19."
The emergency approvals paved the way for the drug to be donated from a national pool of COVID-19 hospitals and were seen as an intermediate step prior to full regulatory approval.
Both drugs are approved for use against malaria and autoimmune diseases such as rheumatoid arthritis and lupus.
Doctors will therefore continue to be able to prescribe them "off label" against COVID-19, although this is strongly recommended by the US health authorities.
Nevertheless, the end of the authorizations is a blow for Trump, who has personally supported HCQ several times and calls it a potential "game changer" because of his gut feelings.
He also said he used the drug to fight infection – but a recent clinical study found it was ineffective for that purpose, too.
HCQ also received ringing recommendations from right-wing news media, including Fox News and Brazilian President Jair Bolsonaro, and in France from supporters of scientist Didier Raoult, who did one of the early experiments that showed positive results.
Overall, it has put politicians against the scientific establishment.
In May, prominent government scientist Rick Bright testified in Congress that he was excluded from his role as a vaccine developer because of concerns about the HCQ and opposition to its widespread use.
Two major clinical trials this month, one in the UK and one in the US and Canada, highlighted the drug's ineffectiveness.
But HCQ was also at the center of an academic scandal when the prestigious The Lancet magazine withdrew a study that claimed the drug increased the risk of death.
The paper was withdrawn after most authors said they could no longer vouch for the authenticity of a record supplied by a small Chicago-based healthcare company.
Despite the affair, the scientific consensus against HCQ's use of COVID-19 appears to have intensified.
(Except for the headline, this story was not edited by NDTV staff and published from a syndicated feed.)