The FDA on Monday revoked its emergency authorization permitting use of the antimalarial drugs hydroxychloroquine and chloroquine to treat the novel coronavirus, citing a lack of evidence of their efficacy.
In late March the agency authorized the drugs, which President Donald Trump touts often as a potential treatment, for patients who were hospitalized with COVID-19 and unable to participate in a clinical trial. It did so knowing the drugs can cause arrhythmias. The agency last month emphasized the risk of potentially life-threatening heart rhythm problems in COVID-19 patients, warning against the drugs’ use outside of a hospital or clinical trial setting.
New scientific evidence, including clinical trial data, led the Biomedical Advanced Research and Development Authority (BARDA) to conclude the drug may not be effective to treat COVID-19 and that any potential benefits don’t outweigh known and potential risks, according to a memo from the FDA.
Hydroxycholoroquine was among the potential COVID-19 drugs under evaluation in RECOVERY, a large randomized clinical trial—considered the goal standard in medical research—that got underway in UK in March. Earlier this month investigators stopped enrolling patients to the hydroxychloroquine arm after a peek at data.
Preliminary results revealed that of the 1,542 patients who received hydroxychloroquine, 25.7 percent died after 28 days. In the comparator group of 3,132 people who received usual care, 23.5 percent died in the same time frame. The difference between the groups was not statistically significant.
Investigators also said there was no evidence of meaningful benefit in duration of hospital stay or other outcomes. These data haven’t yet been peer-reviewed or published in a medical journal. The authors of the study said full results would be shared.
The FDA also said that anecdotes of a decrease in the amount of virus emitted by patients who received the antimalarial treatment, also known as viral “shedding,” hadn’t been consistently replicated.
The revocation of the emergency authorization, comes—like the initial authorization—at the request of BARDA, a previously little-known unit of the Department of Health and Human Services. BARDA’s mandate to is develop countermeasures to threats to public health. Since the start of COVID-19 the division has been especially involved in developing a coronavirus vaccine, floating pharmaceutical companies hundreds of millions of dollars to move ahead efforts to develop and manufacture products to treat and prevent the deadly virus.
The division in April became embroiled in the politically charged debate over the antimalarial drugs’ use following the sudden removal of its director, Rick Bright. A pandemic preparedness expert who had been at BARDA since 2008, Bright was appointed its head in November 2016. Days after he was removed and reassigned to a position within the National Institutes of Health he filed a whistleblower complaint alleging his removal was a politically motivated response by Health and Human Services administrators to his opposition to the “broad use of chloroquine and hydroxychloroquine as lacking scientific merit.”
Monday’s revocation leaves the Gilead Science (NASDAQ: GILD) antiviral drug remdesivir as the sole treatment authorized by the FDA for use in treating those hospitalized with the infection. That permission was granted based on preliminary evidence from studies including a randomized trial conducted by the National Institute of Allergy and Infectious Diseases, which showed that patients who received the drug recovered at a faster rate than those given a placebo.
Many other companies are developing potential treatments for the infection. Cases in the US recently topped 2 million, and more than 115,000 deaths have been recorded.