The Food and Drug Administration today revoked its emergency authorization for two related antimalarial drugs, chloroquine and hydroxychloroquine, to be used for treating COVID-19.
Citing emerging scientific data, the FDA said that the drugs were “unlikely to be effective in treating COVID-19” and that the potential benefits don’t outweigh the known risks, including the incidence of serious cardiac events. For those reasons, the legal criteria for issuing an emergency use authorization “are no longer met,” the FDA said.
The two drugs have been used for decades with FDA approval to treat malaria as well as autoimmune conditions such as lupus and rheumatoid arthritis. The FDA noted that physicians may prescribe approved products for off-label uses if they determine it’s appropriate for treating patients.
In a separate advisory, the FDA warned that the antiviral effect of a different drug, remdesivir, may be reduced if chloroquine or hydroxychloroquine is administered to the same patient. In April, researchers said preliminary results showed that remdesivir appeared to shorten the time required to recover from COVID-19.
The FDA said its warning about the potential drug interaction was based on a recently completed non-clinical study.
Hydroxychloroquine has been in the spotlight in part due to high-profile recommendations from President Donald Trump. Last month, he told reporters that he was taking the drug for a two-week period to stave off a COVID-19 infection and asked, “What have you got to lose?”
Clinical trials have been evaluating the potential benefit of the drugs under close supervision and rigorous conditions. Medical researchers at the University of Washington have been involved in several of those studies, and in a written statement, UW Medicine said those trials will continue despite difficulties with recruitment. Here’s the full statement:
“UW Medicine researchers are continuing hydroxychloroquine trials that are done with outpatients. These trials will have safeguards, such as heart rhythm monitoring and will also exclude people with underlying cardiac, kidney or liver disease. Unlike many previous hydroxychloroquine studies, our researchers are recruiting participants while they are well enough to be at home.
“These trials do not involve the use of hydroxychloroquine for emergency use in treating COVID-19 patients.
“A multi-site clinical trial, led by the University of Washington School of Medicine in collaboration with New York University Grossman School of Medicine, aims to definitively determine whether hydroxychloroquine can prevent transmission in people exposed to the virus. The team is enrolling 1,650 outpatient participants referred by physicians in seven sites who are close contacts of persons with confirmed or pending COVID-19 diagnoses. So far, the trial is 30% enrolled. Ruanne Barnabas, associate professor of global health at the University of Washington schools of Medicine and Public Health, is the principal investigator.
“Researchers are also part of two trials enrolling 2,625 outpatient participants to determine whether a treatment combining a low dose of hydroxychloroquine and azithromycin can prevent hospitalization and death in people with COVID-19. The trial involving 625 outpatients is at 15% enrollment. Christine Johnston, associate professor of medicine in the Division of Allergy and Infectious Diseases at the University of Washington School of Medicine, is the principal investigator.
“A larger trial enrolling 2,000 outpatients, however, has only been able to recruit two people locally and 17 nationally. Ann Collier, professor of allergy and infectious diseases in the Division of Medicine at the University of Washington School of Medicine, is the local principal investigator. She said the negative publicity on hydroxychloroquine and the waning epidemic have made it hard to enroll.
“The science community has agreed that rigorously conducted clinical trials, which closely monitor safety, are the most reliable way to learn about hydroxychloroquine efficacy to prevent and treat COVID-19.”
Update for 2:45 p.m. PT June 15: This report has been updated with the FDA’s warning about drug interaction with remdesivir, and with UW’s statement about clinical trials.
