Medical authorities in China said the drug used in Japan to treat new strains of influenza has proven effective in patients with coronavirus, Japanese media reported on Wednesday

Zhang Xinmin, spokesman for the Chinese Ministry of Science and Technology, said that favipiravir, developed by a subsidiary of Fujifilm, has given encouraging results in clinical trials in Wuhan and Shenzhen involving 340 patients

“He has a high degree of safety and is clearly effective in the treatment,” Zhang told reporters on Tuesday.

Fujifilm Toyama Chemical, which developed the drug – also known as Avigan – in 2014, declined to comment on the claim.

Shares of the company rose Wednesday after Zhang’s comments, closing the morning by 14.7% to 5,207 yen, briefly reaching a daily high of 5,238 yen.

Doctors in Japan use the same drug in clinical trials on patients with coronavirus with mild or moderate symptoms, hoping that this will prevent the virus from multiplying in patients

But a source in the Japanese Ministry of Health suggested that the drug is not as effective in people with more severe symptoms. “We gave Avigan 70 to 80 people, but it doesn’t seem to work so well when the virus has multiplied,” a source told Mainichi Shimbun.

The same limitations were identified in studies involving patients with coronavirus using a combination of HIV antiretroviral drugs lopinavir and ritonavir, the source added.

In 2016, the Japanese government provided favipiravir as an emergency aid to combat the Ebola virus outbreak in Guinea.

Favipiravir will need government approval for full use on patients with Covid-19, as it was originally intended for the treatment of influenza.

A medical professional told Mainichi that the drug could be approved in May. “But if the results of clinical trials are delayed, approval may also be delayed.”