According to the Fujifilm spokesperson, human trials so far have not uncovered any adverse reactions. However, the drug has not been tested on pregnant women because pre-clinical studies indicated possible harm to fetuses.
Like Gilead Sciences’ remdesivir, another antiviral being tested against COVID-19, favipiravir is a selective inhibitor of the RNA polymerase involved in viral replication. Animal studies showed that it’s effective against not only influenza but also West Nile virus, yellow fever, foot-and-mouth disease, and other viruses, Fujifilm says.
So far, the firm notes, the Japanese government is the only group that has ordered large quantities of favipiravir to use against COVID-19. The World Health Organization did not include favipiravir among the four existing drugs it is testing against the disease in a large, multinational trial.