The US regulator has revoked its emergency approval for hydroxychloroquine, an antimalarial drug that was lauded by US president Donald Trump and has been used to treat Covid-19 patients across the world.
The Food and Drug Administration said new data from trials showed the drug did not improve the condition of patients or have an antiviral effect, so the benefits did not outweigh the risks.
Denise Hinton, chief scientist of the FDA, said that hydroxychloroquine and chloroquine, a similar drug, were no longer authorised to treat Covid-19 patients, as of Monday.
“The FDA always underpins its decision-making with the most trustworthy, high-quality, up-to-date evidence available. We will continue to examine all of the emergency use authorizations the FDA has issued and make changes, as appropriate, based on emerging evidence,” she said in a statement.
In a letter to the director of medical countermeasures at another branch of the health department, she wrote that earlier observations that it decreased the shedding of the virus had not been consistently replicated — and recent data from a randomised clinical trial showed no difference between hydroxychloroquine and the “standard of care”: drugs usually used to treat hospitalised patients, such as those administered in intensive care.
Shortly after the pandemic engulfed the US, Mr Trump hailed hydroxychloroquine as a “game-changer” and played down its risks, saying at a press conference: “What do you have to lose?”
Later, he said he had taken the drug himself, trying it as a potential preventive measure to stop him developing Covid-19 after several White House officials had contracted the infection.
Many scientists had expressed concern about the rush to use hydroxychloroquine based on small retrospective studies, not large trials, particularly because of the drug’s known significant cardiac and psychological side-effects.
Misinformation about the drug — propelled by influencers on social media — caused a surge in sales, leading to shortages for people who take it regularly for other conditions such as lupus, as well as reports of some overdoses.
The US had already changed its treatment guidelines to advise that hydroxychloroquine should not be used to treat patients outside of clinical trials.
But earlier this month, an Oxford trial of the drug stopped enrolling participants because it was showing no clinical benefit. At the same time, a University of Minnesota trial to see if hydroxychloroquine could have preventive benefits also found none.
A large-scale study published in the medical journal The Lancet last month appeared to show that the drug was not just ineffective but also increased rates of death and heart problems.
However, those conclusions were undermined when the journal withdrew the paper after serious questions were raised about the source of the data, a Chicago-based data company called Surgisphere, which claimed to have access to electronic health records across the world.