A Japanese team testing the flu drug Avigan as a treatment for the new coronavirus said Wednesday more time was needed to determine its effectiveness, while the government stood by a goal of approving the medication's use this month.

The Fujita Health University School of Medicine said it will continue clinical trials based on the recommendation of an independent panel. The panel found "no safety or other problems" associated with the trials, according to Yohei Doi, the microbiologist heading the effort.

Doi told reporters he had not seen the actual results of an interim analysis by the panel but that its main purpose was not to determine the treatment's effectiveness.

Chief Cabinet Secretary Yoshihide Suga, the government's top spokesman, told reporters there was "no change" in Japan's goal of approval for Avigan as a coronavirus treatment by the end of May, while acknowledging a report that the drug has shown no clear effect against the virus so far.

To achieve that goal, data showing the drug's effectiveness would need to come forward within the next several days. The health ministry is poised to grant the drug fast-track approval.

Avigan developer Toyama Chemical, part of Japan's Fujifilm Holdings, is conducting its own trials of the drug's effectiveness in treating the coronavirus disease COVID-19. Shares in Fujifilm fell more than 2% on Wednesday on the report of the drug's unclear benefits.