US President Donald Trump appears to have finally given up promoting a cheap anti-malarial drug as a possible treatment for the coronavirus after recent tests produced poor results.

The drug hydroxychloroquine, closely related to the commonly used drug chloroquine, is used to treat malaria, rheumatoid arthritis, lupus and other autoimmune diseases.

It has not been proven effective at treating COVID-19.

But until recently, in language familiar to his conservative voters, Mr Trump has touted the drug as being “like a miracle”.

“What do you have to lose?” the president said on April 4, boasting the United States had amassed 29 million doses of the drug.

“Take it.”

The drug has been flying off shelves, leading to widespread shortages for patients who rely on it to treat health conditions for which it was originally approved.

• Read: WHO launches massive trial of four promising antiviral drugs

On Tuesday, American researchers reported hydroxychloroquine showed no benefit to treating COVID-19 after conducting a large study of its use in US veterans hospitals on infected patients.

Of the 368 patients studied, the research showed there were more deaths among those given the drug than those who weren’t.

The study was not a rigorous experiment, nor has it been peer reviewed.

Since the findings were released, Mr Trump appears to have backed down on his support of the drug.

“Obviously there have been some very good reports,” Mr Trump said in response to questions about it at a Tuesday press briefing.

“Perhaps this one’s not a good report, but we’ll be looking at it.”

This week, Dr Rick Bright, a senior government doctor working on a coronavirus vaccine, claimed he was fired for arguing against the use of hydroxychloroquine as a treatment.

“Specifically, and contrary to misguided directives, I limited the broad use of chloroquine and hydroxychloroquine, promoted by the administration as a panacea, but which clearly lack scientific merit,” Dr Bright told The New York Times. 

“While I am prepared to look at all options and to think ‘outside the box’ for effective treatments, I rightly resisted efforts to provide an unproven drug on demand to the American public.”

So why has Mr Trump been promoting hydroxychloroquine as a possible treatment for COVID-19 in the first place?

It all began with a deeply flawed study conducted by a group of scientists in Marseille, France.

Led by controversial French researcher Didier Raoult, the study claimed hydroxychloroquine successfully cured COVID-19 after testing it on 42 infected patients.

French professor Didier Raoult has come under fire for raising false hopes about finding a cure for the coronavirus. Photo: Getty

But the end results excluded six patients who could not have their swabs taken at the end of the study – three were transferred to the intensive care unit, one died, another left the hospital and one stopped taking the treatment due to nausea.

The other 36 eventually recovered, and those who received the drug cleared the virus from their system faster than those who did not.

Around the world, scientists and academics have widely criticised the study for not meeting the accepted standard for clinical trials.

It is now under a post-publication review.

But before the study had been properly scrutinised, the good news had made its way to conservative media giant Fox News.

On March 18, before the study had even been published, a lawyer purporting to be an “adviser” to Stanford University, Gregory Rigano, appeared on Fox News’ Tucker Carlson Tonight, declaring the results “a 100 per cent cure rate against coronavirus”.

From March 23 to 25, Fox News personalities and guests promoted the anti-malarial drug more than 100 times, according to a report by Media Matters for America.

It didn’t take long before the drug was being hailed as a “game changer” by Mr Trump.