A drug that has been used to treat malaria for around 70 years, chloroquine, has been floated as a potential candidate. It appears to be able to block viruses from binding to human cells and getting inside them to replicate. It also stimulates the immune system. A letter to the editor in journal Nature on Feb. 4 showed
chloroquine was effective in combating SARS-CoV-2. A Chinese study emanating from Guangdong
reports chloroquine improved patient outcomes and "might improve the success rate of treatment" and "shorten hospital stay."
Elon Musk, Tesla and SpaceX CEO, and Donald Trump, president of the United States, have both touted chloroquine as a potential treatment candidate.
A more recent correspondence in the journal Nature, on March 18, suggests hydroxychloroquine -- a less toxic derivative of the drug -- is effective at inhibiting SARS-CoV-2 infection. That derivative is widely available to treat disease like rheumatoid arthritis and Chinese researchers have at least seven clinical trials using hydroxychloroquine to treat infection.
The Food and Drug Administration commissioner, Stephen Hahn, discussed the investigations into chloroquine during a White House briefing on March 19. "That's a drug that the president has directed us to take a closer look at as to whether an expanded use approach to that could be done to actually see if that benefits patients," said Hahn.
Donald Trump announced
the FDA approved chloroquine to be used on a "compassionate use" basis on March 19.