A malaria drug that has been tested as a treatment for coronavirus does not save lives, one of the world's largest trials shows.
Hydroxychloroquine received global attention after being promoted by Donald Trump, and then controversy after studies on it were retracted.
The drug has now been pulled from the UK's Recovery trial, which is run by the University of Oxford.
The findings have been passed on to the World Health Organization.
Back at the start of the pandemic, laboratory studies had suggested the malaria drug could affect the virus. Small-scale studies in China and France then hinted it might help patients.
There was a huge amount of hope, as the medicine is cheap and has been safely used to treat malaria and conditions such as lupus and arthritis.
However, the evidence supporting its use for coronavirus has been weak.
'Not a treatment for Covid'
That is why the data from the Recovery trial is crucial. It is the first to test the drug in large numbers of people in a thorough clinical trial.
More than 11,000 patients with Covid-19 are taking part, with 1,542 patients given hydroxychloroquine.
Due to mounting controversy about the drug, the UK's drugs regulator last night asked the Oxford researchers to review their data.
The results showed 25.7% of people taking hydroxychloroquine had died after 28 days. This compared with 23.5% who were given standard hospital treatment.
"This is not a treatment for Covid," said Prof Martin Landray, part of the Recovery trial. The trial immediately stopped using the drug.
The findings come in the wake of deep concern in academic publishing that led to an article being retracted in the Lancet - one of the world's most prestigious medical journals.
It had published a study involving nearly 15,000 patients, from hundreds of hospitals, given hydroxycholoroquine or the similar drug chloroquine.
It concluded the drug was not beneficial and increased the risk of irregular heart rhythms and death. That publication led to the WHO suspending its trials of the anti-malaria drug.
The data had been collected from hospitals by the little-known healthcare firm Surgisphere.
Concerns were raised about the data and then some of the study's authors said they could no longer stand by their publication as Surgisphere would not allow an independent review.
Then the New England Journal of Medicine retracted another paper that had data based on Surgisphere.
Prof Peter Horby, from the University of Oxford which runs the Recovery trial, said: "Hydroxychloroquine and chloroquine have received a lot of attention and have been used very widely to treat Covid patients despite the absence of any good evidence.
"Although it is disappointing that this treatment has been shown to be ineffective, it does allow us to focus care and research on more promising drugs."
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