Some doctors began trying favipiravir to treat coronavirus patients early on, reasoning that its anti-viral properties would be applicable.
Some initial results suggested the drug could help shorten recovery time for patients, with China's ministry of science and technology hailing it as yielding "very good clinical results".
There are currently around five clinical trials ongoing in countries including the US, Italy and Japan, where Fujifilm announced it would be testing the drug's efficacy on a group of 100 patients through until the end of June.
The Japan study will involve administering the drug for up to 14 days to patients between 20 and 74 with mild pneumonia.
