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FDA approves the emergency use of chloroquine for COVID-19

Enlarge / Medical staff at the IHU Mediterranee Infection Institute in Marseille shows packets of a Nivaquine (tablets containing chloroquine) and Plaqueril (tablets containing hydroxychloroquine) on February 26, 2020,.Gerard Julien/Getty Images

On Saturday, the Food and Drug Administration issued an Emergency Use Authorization that will allow patients suffering from COVID-19 to be treated using drugs without clear evidence of the drugs' efficacy. The move comes after President Donald Trump has touted the drugs' potential several times on the basis of tiny, anecdotal trials. There have also been reports of hoarding of the drugs, which are needed by people with some autoimmune disorders.

Potential or hype?

The drugs in question are relatives of chloroquine, specifically chloroquine phosphate and hydroxychloroquine sulfate. Originally developed as an antimalarial, the drug has a variety of effects, including the ability to reduce immune activity. That has made it useful for the treatment of autoimmune disorders such as lupus and rheumatoid arthritis. Given its multiple effects, it's not surprising that the drug also has a variety of side effects, the most significant probably being a slowing of the heart's rhythm that can potentially lead to fatal complications. (Technically, the drug extends the QT interval.)

What does any of this have to do with a coronavirus? As we discussed when exploring potential treatments for SARS-CoV-2, chloroquine can also alter the pH of the compartment in which some viruses are brought into the cell. This can interfere with the process of depositing the virus' genome inside the cell and thus block the virus' ability to reproduce. Experiments in cultured cells infected by SARS-CoV-2 indicated that chloroquine treatments can keep the virus from spreading within the culture.

But cultured cells are very different from the environments the drugs would encounter in the human body, and SARS-CoV-2 obviously behaves differently from earlier coronaviruses. So, ideally, we'd want evidence that it works in humans against the source of the current pandemic.

Unfortunately, however, all we have at present is anecdote. One small trial indicated that the drug was somewhat effective on its own, with its effectiveness enhanced by an antibiotic. But a recent perspective on the drugs' use noted that the trial had "serious methodological flaws," and follow-up work lacked any negative controls to compare with the treated group. There are also indications that the trial was rushed through peer review at a journal edited by one of its authors, who has been involved with research that contains fabricated data.

Meanwhile, a small study performed in China saw no indication that the drug was effective on its own. And it's not clear why an antibiotic, which normally targets bacteria, would enhance the effect of an antiviral treatment. Larger, properly controlled clinical trials are already in progress, but it may be months before they produce enough data for us to make evidence-based decisions here.

Wait for evidence?

But the absence of any other known treatments for this highly infectious disease has led to a number of people latching on to the anecdotal reports about chloroquine, most prominently including President Trump. This has led to a nationwide shortage as doctors and even dentists have handed out unjustified prescriptions or attempted to hoard the drugs for themselves.

This has made the drugs difficult to obtain for those who use them to treat immune disorders, raising the prospect that some of the people with those autoimmune disorders will need extensive care from our overstretched medical system. And at least two people attempting to self-medicate have ended up dead. As a result, some scientists have been harshly critical of Trump's promotion of the drug.

But now the FDA has stepped in. In a letter released on Saturday, the FDA's Chief Scientist, Denise Hinton, responded positively to a request from the Department of Health and Human Services to provide an Emergency Use Authorization for chloroquine-based drugs. According to the law that governs Emergency Use, authorizations can be made after the Secretary of Health and Human Services declares a public health emergency, which has already happened. At that point, the judgement about whether an authorization should be granted is "based on the totality of scientific evidence available to the secretary, including data from adequate and well-controlled clinical trials, if available, it is reasonableRead More – Source

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