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Drug Development

Fujifilm tests favipiravir as a COVID-19 treatment

Japanese government plans to buy at least 2 million courses of the influenza drug

by Katsumori Matsuoka, special to C&EN
April 16, 2020 | A version of this story appeared in Volume 98, Issue 15


A photo of favipiravir pills.
Credit: Fujifilm
Favipiravir, sold as Avigan, was approved in Japan in 2014.
The structure of favipiravir.

Fujifilm is ramping up production of its antiviral treatment favipiravir, one of many approved drugs being tested as a possible treatment for COVID-19. Phase III clinical trials are ongoing in Japan, and the government has ordered 2 million treatment courses. In the US, Fujifilm started Phase II trials earlier this month.

Favipiravir, which Fujifilm sells under the brand name Avigan, has been approved in Japan since 2014 to treat influenza and other viral strains that don’t respond to other drugs. “Avigan tablets are expected to have efficacy against infection with the new coronavirus in view of its characteristic mechanism of action,” says a Fujifilm spokesperson,although the company has yet to present evidence of efficacy.

The Japanese government stated its preference for Avigan to be made in Japan using domestically produced materials. Toyama Chemical, the Fujifilm subsidiary that developed Avigan, will fulfill part of its requirement for a key intermediate, diethyl malonate, from the chemical producer Denka. The firm will restart a plant in Niigata Prefecture that it had closed in 2017 because of global oversupply of the material. The facility was not dismantled and should be able to resume full operations in late May, according to a Denka spokesperson.

In addition, Fujifilm will boost production of intermediates at its Wako Pure Chemical subsidiary and establish partnerships with other raw material suppliers.

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Fujifilm expects to complete small Phase III trials in Japan, involving 100 people, in June. In the US, Phase II trials with 50 people will be conducted at Brigham and Women’s Hospital, Massachusetts General Hospital, and the University of Massachusetts Medical School. Italy and China launched clinical trials of the antiviral in March.

According to the Fujifilm spokesperson, human trials so far have not uncovered any adverse reactions. The drug has not been tested on pregnant women, however, because preclinical 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 influenza as well as West Nile virus, yellow fever, foot-and-mouth disease, and other viruses, Fujifilm says.

The firm notes that thus far 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 multinational trial.


This story was originally posted on April 13, 2020. It was updated on April 16, 2020, with additional information about Fujifilm's production plans and to correctly state what the Japanese government ordered. It ordered 2 million Avigan treatment courses, not 2 million tablets.



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