FDA on Monday rescinded its emergency use authorization (EUA) of the anti-malaria drugs hydroxychloroquine and chloroquine to treat Covid-19, saying the drugs are "unlikely to be effective" in patients with the disease and noting that the medications can cause "serious side effects."

US new coronavirus cases surpass 2.1M, deaths top 116K

FDA's move comes as U.S. officials as of Tuesday morning reported 2,124,000 cases of the new coronavirus—up from 2,086,900 cases as of Monday morning.

Data shows that Puerto Rico and at least 20 states—Alabama, Alaska, Arizona, Arkansas, Florida, Georgia, Hawaii, Louisiana, Missouri, Nevada, North Carolina, Oklahoma, Oregon, South Carolina, Tennessee, Texas, Utah, Vermont, Wyoming, and Montana—saw their growth rates of newly reported cases of the novel coronavirus accelerate over the past 14 days.

Meanwhile, the data shows that the growth rates of newly reported cases over the past two weeks remained nearly constant in California, Idaho, Indiana, Iowa, Kansas, Kentucky, Mississippi, New Mexico, North Dakota, South Dakota, Washington, and Guam.

In addition, Washington, D.C., and 19 states—Colorado, Connecticut, Delaware, Illinois, Maine, Maryland, Massachusetts, Michigan, Minnesota, Nebraska, New Hampshire, New Jersey, New York, Ohio, Pennsylvania, Rhode Island, Virginia, Wisconsin, and West Virginia—saw their growth rates of newly confirmed cases decrease over the past 14 days.

As of Tuesday morning, U.S. officials also had reported a total of 116,207 U.S. deaths linked to the new coronavirus—up from 115,472 deaths reported as of Monday morning.

FDA revokes EUA for hydroxychloroquine, chloroquine to treat Covid-19

As the numbers of newly reported coronavirus infections and related deaths continue to rise in America, scientists and public health officials are scrambling to find a vaccine against the virus and treatments for Covid-19, the disease caused by the virus.

Two experimental treatments that researchers have been evaluating are the anti-malaria drugs hydroxychloroquine and chloroquine. President Trump has widely touted hydroxychloroquine as a potential treatment for Covid-19, and FDA in March issued an EUA to allow providers to use hydroxychloroquine and chloroquine to treat patients with Covid-19 in clinical trials or hospital settings.

But health experts have noted that neither hydroxychloroquine nor chloroquine has been approved to treat the disease. In addition, experts have said the drugs can cause patients to experience severe side effects, including critical heart rhythm problems. In April, FDA warned providers not to use chloroquine and hydroxychloroquine to treat Covid-19 patients outside of a clinical trial or hospital setting because the drugs could cause patients to experience "serious heart rhythm problems."

Further, research has suggested that hydroxychloroquine does not effectively prevent or treat Covid-19. Earlier this month, data from the first randomized controlled clinical trial examining whether hydroxychloroquine could protect people from contracting the new coronavirus found the drug did not prevent people who were exposed to the virus from becoming infected. In addition, researchers this month released data from a study evaluating potential treatments for Covid-19 that found hydroxychloroquine showed no benefits for Covid-19 patients.

On Monday, FDA revoked its EUA for hydroxychloroquine and chloroquine to treat Covid-19, following a request from HHS' Biomedical Advanced Research and Development Authority (BARDA) to withdraw the authorization. BARDA is responsible for supplying treatments during public health emergencies.

FDA's Chief Scientist Denise Hinton in a letter sent Monday to Gary Disbrow, BARDA's acting director, wrote that FDA withdrew the EUA based on the latest science, which suggests chloroquine and hydroxychloroquine are ineffective treatments for Covid-19.

"Today's request to revoke is based on new information, including clinical trial data results, that have led BARDA to conclude that this drug may not be effective to treat [Covid-19] and that the drug's potential benefits for such use do not outweigh its known and potential risks," Hinton wrote. She continued, "In light of ongoing serious cardiac adverse events and other serious side effects, the known and potential benefits of [the drugs] no longer outweigh the known and potential risks for the authorized use."

FDA warns against using hydroxychloroquine with remdesivir to treat Covid-19

FDA on Monday also warned against using hydroxychloroquine in combination with remdesivir, a drug that has shown some efficacy in treating Covid-19.

FDA said new evidence from a non-clinical laboratory showed the co-administration of hydroxychloroquine and remdesivir "is not recommended as it may result in reduced antiviral activity of remdesivir." The agency noted that it has not seen evidence of reduced antiviral activity of remdesivir in clinical trials where the drug is being used to treat Covid-19 patients in tandem with hydroxychloroquine, but said it is continuing to review all data related to remdesivir as a potential treatment for Covid-19.

FDA said it is updating it fact sheet for providers that accompanies remdesivir to reflect the agency's new warning (Facher, STAT News, 6/16; New York Times, 6/16; Fernandez, Axios, 6/15; Perrone, Associated Press, 6/15; Roy, Reuters, 6/15; Lovelace, CNBC, 6/15; New York Times, 6/16).