• As the coronavirus pandemic rages on, some drugs are showing promising potential to treat patients with COVID-19, the disease caused by the novel coronavirus.
  • There are no approved treatments or vaccines for the coronavirus, but researchers are testing a slew of existing drugs to see if they may work.
  • One of those drugs is called chloroquine. It’s a widely used anti-malaria pill that was first approved in the US in 1949.
  • Countries including China, South Korea, and Belgium, have added it to treatment guidelines for COVID-19 as anecdotal reports have come in suggesting it may work.
  • There is no peer-reviewed clinical data showing chloroquine works against COVID-19. But that hasn’t stopped doctors from using it, US prescriptions from spiking, and even Elon Musk from tweeting about it as a potential treatment.
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In the scramble to find drugs to treat the coronavirus pandemic, one potential treatment has been flying relatively under the radar, despite promising early results.

The drug is chloroquine, a widely prescribed anti-malaria pill that was first approved in the US in 1949. Early laboratory research and anecdotal reports from using the drug in patients with COVID-19 have shown encouraging signs that it may work to fight this virus.

As dozens of drug companies have rushed into research projects to develop antibodies and other next-generation therapeutics, chloroquine stands out as a potentially simple, cheap, and scalable treatment, though we haven’t yet seen data from any randomized clinical trials, the gold standard of medical research.

“If clinical data confirm the biological results, the novel coronavirus-associated disease will have become one of the simplest and cheapest to treat and prevent among infectious respiratory diseases,” a group of French researchers wrote on February 15 in the International Journal of Antimicrobial Agents.

One of the three authors of that article was Didier Raoult, a prominent infectious disease expert who's running a clinical trial in France to test a version of the drug called hydroxychloroquine on a few dozen patients with COVID-19. It's one of many clinical studies going on around the world in testing chloroquine or hydroxychloroquine.

Early reports of Raoult's trial in the French press were positive, with Raoult saying chloroquine appeared to shorten the time that COVID-19 patients are infectious.

When combined with the antibiotic azithromycin, it also reduced the viral load in these patients, he added. Azithromycin helps fight lung infections that can come along with COVID-19, and also may play a role in fighting the virus, Medscape reported.

The French government plans to expand testing of chloroquine on a larger scale.

Chloroquine has 'been underappreciated'

Steven Seedhouse, a biotech analyst at Raymond James, sees chloroquine as just as promising as any treatment option for COVID-19. That includes remdesivir, an antiviral drug being developed by the giant biotech company Gilead Sciences. World Health Organization officials have called remdesivir "the most promising candidate" against the coronavirus.

He recently analyzed the early evidence for three top drugs being tested against COVID-19: remdesivir, chloroquine, and Kaletra, an HIV drug sold by AbbVie. He concluded that chloroquine was the most promising candidate.

"If we had to pick one of the three at this point that actually seems most likely to have the biggest impact on treating COVID-19 in the coming months/years, it would be chloroquine," he wrote

Early reports of chloroquine working have also caught the attention of Elon Musk. The Tesla CEO tweeted on March 16 that it might be worth considering chloroquine for COVID-19. He said the drug saved his life when he faced a serious case of malaria.

Repurposed antiviral drugs aren't likely to be cure-alls for the virus, but they are the only near-term treatment options. It will take months, if not years, to determine if a new drug or vaccine is safe and effective.

Vaccines, in particular, are seen as the gold standard for infectious diseases - protecting people from infections in the first place.

But if drugs like chloroquine and remdesivir work, they could bring major relief to healthcare systems around the world that are feeling the weight of a pandemic.

In the US, there are widespread concerns about the likelihood that hospitals will run out of beds and ventilators as the virus spreads, forcing doctors into difficult rationing decisions. That's already happening in Italy.

Remdesivir, given as a 10-day intravenous infusion, could shorten hospital stays and lower ventilator use if it can help patients with serious COVID-19 cases recover faster.

Chloroquine is being tested to treat coronavirus, and to prevent people from catching it

Chloroquine, as a simple pill, could prevent some COVID-19 patients from worsening to the point of needing hospitalization in the first place.

Researchers also plan to test chloroquine in healthcare workers to see if it can help prevent them from getting the virus in the first place.

The drug can have serious side effects, such as causing damage to an individual's eyes. It can also cause headaches, dizziness, and stomach problems ranging from discomfort to vomiting and diarrhea.

For both remdesivir and chloroquine, there is no peer-reviewed clinical data about whether they work to halt the coronavirus. Raymond James' Seedhouse said that even in the face of a pandemic, it is essential to stick to evidence-based approaches.

"All we have is some preclinical rationale and some mechanistic rationale, but no hard randomized clinical data yet," Seedhouse said. "I think it's appropriate to be cautious on chloroquine and anything else."

US prescriptions are spiking, as the UK guards its supply

While peer-reviewed results are the standard in medicine, the lack of that data hasn't prevented the world from acting.

China has said that chloroquine is effective against COVID-19, the state-owned Xinhua news agency reported on February 17. Countries including China, South Korea, and Belgium have added chloroquine to their treatment guidelines.

US physicians don't appear to be waiting for data, either. Prescriptions for chloroquine are surging, according to recent tracking data from IQVIA. For the weeks of February 21, February 28, and March 6, weekly prescriptions have grown from 531 to 957 to 1,290, according to Raymond James.

Doctors in the US have broad authority to prescribe approved medications for what are known as off-label uses, or conditions that the drug isn't approved to treat.

In the past month, the UK has added both chloroquine and hydroxychloroquine to a list of drugs that drug wholesalers cannot export out of the country because UK patients need them and exporting them may lead to a shortage in the UK.

Early reports of success 'should be taken seriously'

Andrea Savarino is an Italian scientist who has worked at the Italian Institute of Health, the country's top medical research body, since 2006. He has been studying chloroquine and its potential uses for even longer than that, starting as a virologist in 1994.

In the 2002-2003 outbreak of SARS, which is also a coronavirus, Savarino showed that chloroquine may be a useful weapon against that virus in laboratory research. But by the time his research was published in The Lancet in November 2003, the outbreak had dissipated and there were no human cases available to test.

"There has been a number of press releases, unfortunately not yet papers, but even the local experiments are things that should be taken seriously," Savarino told Business Insider. "Chloroquine plus the HIV inhibitors has produced interesting results, at least curative results, both in China and Australia."

In Australia, researchers at the University of Queensland have said a combination of chloroquine and the HIV drug Kaletra led to the complete recovery of some of the first COVID-19 patients in Australia.

"It is a potentially effective treatment," University of Queensland Centre for Clinical Research director David Paterson told the Australian news site news.com.au.

Savarino said he has heard anecdotal accounts from other countries as well, including Japan, India, and Thailand.

"Given these promising results, I am of course optimistic but I cannot give percentages of success as of now," Savarino said. He emphasized the need to collect more data before reaching conclusions.

Savarino said he is developing an online platform that will collect hydroxychloroquine data on COVID-19 patients across Italy, and eventually add in other countries. He hopes to get the site going in the next few days, he said, and will make the data widely available as soon as possible.

Ultimately, Savarino said he thinks a combination of two or three drugs will be found to be the most effective treatment for COVID-19, in a similar way that therapies using multiple drugs have become the standard for treating HIV.