FDA pulls emergency use of hydroxychloroquine hyped by Trump for treating Covid-19, says it could pose risks
The US Food and Drug Administration (FDA) has withdrawn its emergency use authorization (EUA) for two drugs -- hydroxychloroquine and chloroquine -- to treat hospitalized Covid-19 patients, saying that they are unlikely to be effective and could carry potential risks.
“It is no longer reasonable to believe that oral formulations of HCQ (hydroxychloroquine) and CQ (chloroquine) may be effective in treating Covid-19. Further, in light of ongoing reports of serious cardiac adverse events and several newly reported cases of methemoglobinemia in Covid-19 patients, the agency has concluded that the known and potential benefits of CQ and HCQ do not outweigh the known and potential risks for the authorized uses. Accordingly, FDA revokes the EUA for emergency use of HCQ and CQ to treat Covid-19. As of the date of this letter, the oral formulations of HCQ and CQ are no longer authorized by FDA to treat Covid-19,” said the agency in a statement.
US President Donald Trump has been hyping hydroxychloroquine as a potential therapy against coronavirus which has not been approved. When questioned about the decision, Trump said, “I took it and I felt good about taking it. I don’t know if it had an impact, but it certainly didn’t hurt me. I feel good.” On March 28, 2020, the FDA approved the emergency use of oral formulations of chloroquine phosphate and hydroxychloroquine sulfate for the treatment of coronavirus patients. According to the FDA, based on information available to the agency at the time, it “determined that CQ and HCQ may be effective” in treating Covid-19. The agency had limited the use of the authorized products to adults and adolescents who weigh 50 kg or more and are hospitalized with Covid-19 when participation in a clinical trial is not available, or participation is not feasible. The FDA also subsequently cautioned against the use of hydroxychloroquine or chloroquine for Covid-19 outside of the hospital setting or a clinical trial due to the risk of heart rhythm problems.
“Emerging data and published literature have raised new questions on whether CQ and HCQ may be effective in treating Covid-19 and whether CQ and HCQ’s known and potential benefits outweigh the known and potential risks associated with their authorized use. As part of the agency’s ongoing review of the appropriateness of the EUA, FDA scientific staff conducted reviews of these new data and also conducted new analyses of information known at the time of initial authorization,” it says.
According to the analysis, the FDA says that the suggested dosing regimens for CQ and HCQ are unlikely to produce an antiviral effect. The FDA also said that as of May 6, there were 347 adverse events in Covid-19 patients taking hydroxychloroquine and 38 in those taking chloroquine. The majority of cases, 69%, involved men with a median age in the early 60s. Five cases reported HCQ use through the EUA. The review states that there were 109 cases with serious cardiac episodes, including 80 cases of a serious heart rhythm disorder called QT prolongation. Other patients had different rhythm abnormalities, and 25 of the 109 died. There were also serious adverse events not affecting the heart in 113 cases, including liver abnormalities.
The agency’s review further says that recent data from a large randomized controlled trial showed no evidence of benefit for mortality or other outcomes such as hospital length of stay or need for mechanical ventilation of HCQ treatment in hospitalized patients with the new coronavirus. “Earlier reports of decreased viral shedding with CQ or HCQ treatment have not been consistently replicated and recent data from a randomized controlled trial assessing the probability of negative conversion showed no difference between HCQ and standard of care alone,” says the FDA. In a separate statement, the FDA also warned that hydroxychloroquine should not be used with remdesivir for treating coronavirus patients as it may weaken the effectiveness of remdesivir. Following an evaluation, the FDA issued had an emergency use authorization in May 2020 allowing for remdesivir to be distributed in the US and to be administered intravenously by healthcare providers, as appropriate, to treat suspected or laboratory-confirmed Covid-19 in adults and pediatric patients hospitalized with severe disease.
“The FDA is warning healthcare providers about a newly discovered potential drug interaction related to the investigational antiviral drug remdesivir, which has received emergency use authorization for the treatment of hospitalized Covid-19 patients with severe disease,” said the agency. “Based on a recently completed non-clinical laboratory study, the FDA is revising the fact sheet for healthcare providers that accompanies the drug to state that co-administration of remdesivir and chloroquine phosphate or hydroxychloroquine sulfate is not recommended as it may result in reduced antiviral activity of remdesivir. The agency is not aware of instances of this reduced activity occurring in the clinical setting but is continuing to evaluate all data related to remdesivir,” the statement cautioned.