Japan has given up on its target of approving Fujifilm Holdings Corp.'s anti-influenza drug Avigan this month as a treatment for coronavirus patients after an interim clinical test report showed no clear efficacy, health minister Katsunobu Kato said Tuesday.

"We will continue the clinical study and clinical tests (of the drug) in June and onwards. There is no change in our policy to approve the drug swiftly if its efficacy (against the coronavirus) is confirmed," Kato told a press conference.

There is a belief that Avigan, also known as favipiravir and developed by Fujifilm Holdings' unit Fujifilm Toyama Chemical Co., can be used as a treatment for the COVID-19, the respiratory illness caused by the coronavirus.

In earlier this month, Prime Minister Shinzo Abe expressed hope that the homegrown drug would receive approval by the end of this month, despite no clear evidence of efficacy and safety.

Supplied photo shows tablets of the anti-influenza drug Avigan.
(Photo courtesy of Fujifilm)(Kyodo)

In response to Abe's remarks, some experts had raised concerns that the government was rushing to approve it and undermining the strict medical procedures in place to authorize the use of a drug.

Kato said the government initially aimed to approve the drug if the interim results of clinical tests, conducted by a team led by Fujita Health University, showed extremely high effectiveness in treating COVID-19.

But a third-party panel that assessed the results of the interim report, released in the middle of this month, said that it was too early to judge it scientifically, prompting the continuance of the clinical trials, according to Kato.

The drug cannot be administered to expectant mothers or women who are likely to become pregnant as it may cause birth defects.

Aside from the tests carried out by Fujita Health University, Fujifilm is also conducting clinical tests of Avigan on its own and are set to continue through the end of June.

It said Friday it is still discussing the matter with regulatory authorities and cannot say when it can apply for approval of the drug.

The company is ramping up production of Avigan, as the government has earmarked about 13.9 billion yen ($128 million) in an extra budget for fiscal 2020 to triple the national stockpile of Avigan, enough to treat 2 million people infected with the coronavirus.

Kato said, separately, some 3,000 COVID-19 patients in Japan have so far been prescribed Avigan as a part of an "observational study."

"I have heard that there have not been new cases of side effects that may pose safety issues," Kato said.

But medical experts said results of an "observational study," which are different from that of randomized, controlled clinical studies and cannot be used as a major basis in approving the drug.

The government is also enthusiastic about offering the drug for free to foreign countries who are interested in using it for clinical studies. Foreign Minister Toshimitsu Motegi has said around 80 countries have expressed interest.

As Avigan can inhibit the replication of the virus in cells, experts say it may bring about improvements for those with mild symptoms or those who have recently been infected.

If approved, Avigan would be Japan's second authorized COVID-19 treatment after the antiviral drug remdesivir developed by U.S. firm Gilead Sciences Inc., which was given the green light earlier this month under an expedited review.

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