An expert panel of Japan's health ministry has approved the expanded use of the anti-influenza drug, Avigan, to treat a tick-borne viral infection called severe fever with thrombocytopenia syndrome, or SFTS.
Once the ministry formally greenlights the medication, it will become the world's first therapeutic drug for SFTS.
Patients with SFTS mostly get the viral infection through tick bites. Symptoms include fever and diarrhea, but no effective medication is currently available.
The health ministry says up to 30 percent of SFTS cases in Japan have been fatal.
Avigan was developed by Fujifilm Toyama Chemical.
The company sought the health ministry's approval for the drug's use against SFTS last August, saying it had obtained data on its efficacy.
On Friday, the health ministry panel confirmed that the drug is effective and that there are no serious concerns over its safety.
Avigan was initially approved as an anti-flu drug in Japan in 2014, and is stockpiled by the government.
The drug cannot be used by expecting mothers or women who might be pregnant, as animal testing showed that it could cause deformities in fetuses.