The facts about chloroquine and when it could be FDA-approved.

By Claire Gillespie
Updated March 24, 2020

A drug called chloroquine, currently used to treat malaria as well as inflammatory conditions like lupus and rheumatoid arthritis, is getting a lot of attention as a potential treatment for people with the COVID-19 coronavirus. But is the excitement overblown?

President Trump touted chloroquine (as well as a similar drug, hydroxychloroquine) during a March 19 White House briefing, claiming it would be made available “almost immediately” to treat COVID-19. "It's been around for a long time, so we know ... if things don't go as planned, it's not going to kill anybody," said Trump, who called the drug a "game changer."

However, the truth is the drug has not been approved by the Food and Drug Administration (FDA) for use in the treatment of coronavirus. It remains under review as a potential treatment for COVID-19 patients.

Tragically, an Arizona man died after consuming a chemical treatment containing chloroquine that he and his wife had used to treat their koi pond, NBC News reported. The couple, in their 60s, reportedly ingested small amounts of the fish tank cleaner after the wife heard the President talk about the potential benefits of chloroquine. Shortly after taking the substance, she and her husband fell violently ill, and she called 911. The man died shortly after arriving at the hospital, while she remained hospitalized, according to the report.

The couple had hoped to prevent COVID-19, but no drug have been proven to prevent the infections. What's more, the product they consumed, though useful for ridding fish tanks of parasites, is toxic to humans, says The Washington Post. The active ingredient is not the same as the medication that is being administered in clinical trials to determine whether it might benefit people with coronavirus.

In a statement posted to its website, the FDA said that it has been working with other government agencies and academic centers to determine whether chloroquine can be used to reduce the duration of symptoms in people with mild- to moderate cases of COVID-19. The agency also wants to see whether treating patients with chloroquine would help to prevent the spread of the disease.

Bottom line: "Studies are underway to determine the efficacy in using chloroquine to treat COVID-19," the FDA stated.

During the White House coronavirus briefing, FDA commissioner Stephen Hahn confirmed that Trump had directed the FDA to take a closer look at chloroquine to see if it could benefit coronavirus patients. But he added that testing would be done in the setting of “a large, pragmatic clinical trial to actually gather that information,” according to the Post.

Hahn didn’t give an exact timeline, but he said, "over the next couple of weeks, we'll have more information that we're really pushing hard to try to accelerate... and that will be a bridge to other therapies that will take us three to six months to develop," according to CNN. "And this is a continuous process—there is no beginning and end."

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Scientists around the world have been racing to find a treatment for the new coronavirus. More than 80 clinical trials are reportedly running or pending in China and more are scheduled to start in many other countries, including the US, England, and South Korea. 

Using antimalarial drugs to treat the coronavirus is something that billionaire businessman Elon Musk thinks has potential. He tweeted on March 16 that it might be “worth considering chloroquine for C19.” 

Musk apparently gave it some more thought and followed it up the next day with “Hydroxychloroquine probably better.”

So what are chloroquine and hydroxychloroquine, and how could they help fight the new coronavirus? 

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A systematic review on the efficacy and safety of chloroquine for the treatment of COVID-19 was published in the Journal of Critical Care on March 10. Review authors concluded that there is “rationale, pre-clinical evidence of effectiveness and evidence of safety from long-time clinical use for other indications to justify clinical research on chloroquine in patients with COVID-19.” Translation: it’s worth a closer look. 

Chloroquine (Aralen) and hydroxychloroquine (Plaquenil) were first prescribed for malaria in 1944. They can be given before exposure to malaria, which is caused by a parasite transmitted by infected mosquitos, to prevent infection. The drugs are also used as treatment after infection. 

Antimalarial drugs are sometimes prescribed to people with lupus, per Johns Hopkins Lupus Center in Maryland. Hydroxychloroquine is more commonly prescribed because it is generally believed to cause fewer side effects, whereas chloroquine has a reputation for more serious side effects but may be prescribed in situations where hydroxychloroquine cannot be used.

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Lab studies (including research published in Virology Journal in 2005) show that chloroquine is effective at preventing as well as treating the virus that causes severe acute respiratory syndrome (SARS), which is caused by another strain of coronavirus. 

And recent research from China found that the protein spikes on the surface of the COVID-19 virus are similar to the protein spikes found on the surface of the SARS virus. While the coronavirus uses lots of different proteins to replicate and invade cells, protein spikes are the main proteins it uses to bind to a receptor (another protein that creates an entryway to a human cell). When that happens, people become infected. 

Chloroquine works against SARS by acting as a barrier between those receptors, which then interferes with the ability of the virus to bind to human cells. 

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Although data is limited, the early findings are good. Research from China, published in BioScience Trends on February 19, found that treating patients with COVID-19-associated pneumonia with chloroquine may shorten the length of hospital stays and improve patient outcomes.

But until we have sufficient data from rigorous human trials, there's no way to say definitively whether chloroquine or hydroxychloroquine may help, or harm, people with COVID-19.

The information in this story is accurate as of press time. However, as the situation surrounding COVID-19 continues to evolve, it's possible that some data have changed since publication. While Health is trying to keep our stories as up-to-date as possible, we also encourage readers to stay informed on news and recommendations for their own communities by using the CDCWHO, and their local public health department as resources.

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