Chloroquine and a related drug, hydroxychloroquine, in combination with the antibiotic azithromycin, have been presented as a potential coronavirus treatment by Donald Trump despite the lack of evidence.
Study ends the same day that a letter in the journal Nature raised the alarm about the serious heart risks associated with Covid-19 patients taking the drugs and the United States Food and Drug Administration set out guard against serious cardiac complications.
Donald Trump has previously urged Americans to take hydroxychloroquine, although he has apparently steered clear of the drug in recent days, and even suggested on Thursday that disinfectant injections could cure Covid-19 – an idea that was quickly refuted by experts, who warned the public “please do not inject bleach”.
The Brazilian study, published in the Journal of the American Medical Association Network Open (Jama), was halted by a safety oversight committee before even a quarter of the 440 planned patients were enrolled. Eighty-one patients with Covid-19 or suspected Covid-19 received a daily regimen of chloroquine. The randomized clinical trial separated patients into a high-dose and low-dose group.
The researchers plan to assess their results after 28 days.
But after 13 days, six of the 40 patients in the low-dose group had died, compared to 16 of the 41 patients in the high-dose group. In addition, five patients in the high-dose group had underlying heart disease, three of whom died.
“Despite these discouraging results, several other observations preclude a firm conclusion that high-dose chloroquine was toxic,” said the authors of a commented article.
Hydroxychloroquine and chloroquine in combination with azithromycin were first proposed as potential treatments for Covid-19 in a French study described as “meaningless”. The newspaper later said the study did not meet publication standards.
But by the time the review disowned the flawed study design, the media had already promoted the unproven and risky drug combination. The treatment was tweeted by tech billionaire Elon Musk and picked up by Fox News. He was later touted by Trump as a potential “game changer” despite serious risks and the lack of safety and efficacy data. At least one man died and a woman was hospitalized after taking chloroquine.
The letter published in Nature warned of serious heart problems and the risk of “sudden cardiac death” in patients treated with hydroxychloroquine and azithromycin.
In the letter, which unlike a study that is not peer-reviewed, a New York doctor described the reaction of 84 Covid-19 patients to a five-day, twice-daily regimen. The patients were followed by an electrocardiogram. The two drugs have been shown to independently increase the risk of “sudden drug-related heart death”.
Of the 84 patients, nine showed signs of potentially severe heart arrhythmia that could increase the risk of cardiac arrest, although none had a heart attack. By the end of the study, four patients had died from multi-organ failure, 16 patients had been discharged and 64 others had remained in hospital. The authors concluded that patients following the regimen should be “constantly monitored” for heart problems.
Despite the lack of evidence that it is an effective treatment for Covid-19, some hospitals in the United States have used hydroxychloroquine to treat critically ill patients in the hope of obtaining certain benefits.
However, scientists have repeatedly called for caution. The American Thoracic Society (ATS) and the Infectious Diseases Society of American have both requested that the drug be used only in clinical trials.
In clinical guidelines to doctors, Dr. Kevin C Wilson, chief of records and patient education at ATS, said that while some laboratory results showed antiviral effects against the virus, they had not yet been reproduced with patients.
“So the bottom line is, whether hydroxychloroquine and chloroquine provide benefits to patients with Covid-19 are unanswered questions. “