The Food and Drug Administration has revoked the emergency use authorization (EUA) for chloroquine phosphate and hydroxychloroquine sulfate based on emerging data suggesting that these agents are unlikely to be effective against coronavirus disease 2019 (COVID-19).

According to the FDA, a letter was sent to the Agency from the Biomedical Advanced Research and Development Authority requesting revocation of the EUA, which allowed chloroquine and hydroxychloroquine donated to the Strategic National Stockpile to be used to treat certain hospitalized patients with COVID-19 outside of clinical trials. The request was based on new information suggesting that the potential benefits of chloroquine and hydroxychloroquine in treating COVID-19 no longer outweighed the risks. 

“While additional clinical trials continue to evaluate the potential benefit of these drugs in treating or preventing COVID-19, we determined the emergency use authorization was no longer appropriate,” said Patrizia Cavazzoni, MD, acting director of the FDA’s Center for Drug Evaluation.

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This determination was based on several factors including:

  • Data suggesting that the dosing regimens for these drugs were unlikely to produce an antiviral effect.
  • No consistent data showing that the drugs decreased viral shedding, as well as a recent study revealing no difference between hydroxychloroquine use and standard of care with regard to the probability of negative conversion.
  • The National Institutes of Health (NIH) guidelines and other US treatment guidelines (Infectious Diseases Society of America Guidelines on the Treatment and Management of Patients with COVID-19 and The Johns Hopkins ABX Guide), recommending against the use of these agents outside of clinical trials.
  • Data from a large randomized trial showing no evidence of benefit for mortality or other outcomes (this research was recently retracted due to concerns over data integrity). 

Additionally, there have been reports of cardiovascular complications associated with these drugs, including QT interval prolongation, ventricular tachycardia, and ventricular fibrillation. These adverse events were reported from both hospital and outpatient settings and in some cases resulted in death.

“We’ve made clear throughout the public health emergency that our actions will be guided by science and that our decisions may evolve as we learn more about the SARS-CoV-2 virus, review the latest data, and consider the balance of risks versus benefits of treatments for COVID-19,” said FDA Deputy Commissioner for Medical and Scientific Affairs Anand Shah, MD “We will continue to examine all of the emergency use authorizations the FDA has issued and make changes, as appropriate, based on emerging evidence.”

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This article originally appeared on MPR