Washington (AFP)

The American Medicines Agency (FDA) granted an emergency use authorization on Friday for the experimental antiviral remdesivir, based on a large American trial which concluded that it shortens the recovery of most patients by several days severely affected by Covid-19.

"I am pleased to report that Gilead has received emergency use clearance from the FDA for remdesivir," said President Donald Trump from the White House.

The authorization allows the remdesivir to be used by hospitals for critically ill Covid-19 patients who require oxygen, for example on artificial respirators, without the need to participate in a clinical trial.

"It is reasonable to believe that remdesivir may be effective against Covid-19 and that, since there are no adequate, approved or available alternative treatments, the known and potential benefits for treating this severe and deadly virus outweigh the known and potential risks posed by the use of the drug, "said the FDA.

Remdesivir will be distributed as a priority to hospitals in the cities most affected by the pandemic in the United States, a distribution to be coordinated by the United States government, Gilead said in a statement.

The American laboratory, whose boss was in the Oval Office for the announcement, will donate 1.5 million doses, enough to treat at least 140,000 patients.

The drug is given intravenously for 10 days, but emergency clearance covers treatment in five days, as a study by Gilead showed that the effect was similar.

Hydroxychloroquine, a malaria drug, was first approved by the FDA on March 28, but since then the FDA and a government panel have issued warnings for serious side effects on the heart.

- One track among others -

Multiple treatments for Covid-19, the disease caused by the new coronavirus Sars-Cov-2, are being evaluated in Asia, Europe and the United States, but these are the results of large clinical trials with placebo which are the most anticipated, especially in Europe (Discovery trial).

An experimental drug originally developed to treat patients with Ebola haemorrhagic fever, but never approved for any disease, remdesivir is the first therapy to have demonstrated some effectiveness in such a large trial, more than a thousand patients, even if l The effect is considered modest.

Inpatients treated with remdesivir had their recovery time cut by four days (median), from 15 to 11 days, according to results released Wednesday by the United States Institutes of Health, which coordinated the trial.

"Although the results are clearly positive from a statistical point of view, they are modest," said director of the National Institute for Infectious Diseases (NIAID), Anthony Fauci, on Thursday.

But it is however the "demonstration" that the mode of action of remdesivir is effective, and it could therefore open the way to better treatments, according to the eminent researcher.

The results suggest that remdesivir also reduces the risk of death, but this result is below the statistical reliability threshold. 8% of the treated patients, compared to 11.6% in the control group, died during the trial.

But the full results of the study have not been published, which has drawn criticism from the scientific community who are waiting for the study to be evaluated and published by a medical journal.

And a smaller trial in Wuhan, China, which was published in a medical journal (The Lancet), found no efficacy with remdesivir.

Other therapeutic approaches include the combination of hydroxychloroquine and an antibiotic, for which the studies are of inferior quality and discordant.

Ditto for the drug track to prevent the inflammatory outbreak apparently caused by the coronavirus. Tocilizumab is effective, according to a French study, but a similar molecule used against arthritis (sarilumab, brand Kevzara) failed to help patients in another trial with placebo.

© 2020 AFP