Japan took steps Saturday to fast-track its approval of the anti-viral drug remdesivir for the treatment of new coronavirus patients, as the domestic death toll topped 500 including cases from a cruise ship.

The government revised a Cabinet order so it can drastically simplify steps to authorize medicines for COVID-19, the illness caused by the virus, on condition such drugs have been approved in the United States, Britain, Canada, Germany and France.

The move by the Japanese government came after the U.S. Food and Drug Administration said Friday it has authorized the emergency use of the drug for those hospitalized with severe illness caused by the virus.

(Supplied file photo shows anti-viral drug Remdesivir.)

Health minister Katsunobu Kato told reporters Saturday he has directed government officials to give the green light to an application by U.S. firm Gilead Sciences Inc., the developer of remdesivir, for approval in "about a week."

Kato added the company is expected to apply for authorization in Japan "within the next few days." If approved, it will be the first recognized coronavirus treatment in the country.

Over 15,000 COVID-19 cases have so far been confirmed in Japan, including about 700 from the Diamond Princess cruise ship that was quarantined in Yokohama near Tokyo in February, with more than 500 fatalities including 13 ship passengers, according to a tally by Kyodo News.

Remdesivir was developed by Gilead Sciences as a possible treatment for Ebola, but it has not been licensed or approved anywhere globally. Side effects such as deterioration in liver and kidney functions are feared.

(Health minister Katsunobu Kato)

In announcing the emergency use, the U.S. Food and Drug Administration said in a statement, "While there is limited information known about the safety and effectiveness of using remdesivir to treat people in the hospital with COVID-19, the investigational drug was shown in a clinical trial to shorten the time to recovery in some patients."

Clinical trials have been under way to confirm the effectiveness and safety of its use for COVID-19 patients around the world, including Japan.

Under the U.S. emergency use authorization, the drug will be administered intravenously for patients with low blood oxygen levels as well as those needing oxygen therapy or more intensive breathing support such as a mechanical ventilator.

According to a study recently published by the New England Journal of Medicine, the drug demonstrated effectiveness in nearly 70 percent of 53 coronavirus patients with severe symptoms, while it caused serious side effects, such as deterioration of kidney and liver functions, in a quarter of them.

Moves to develop therapeutic drug and vaccines have been accelerating worldwide.

In Japan, the anti-influenza drug Avigan is also going through clinical tests on COVID-19 patients, which will last through June. A scientific study in China has shown its effectiveness in treating the disease.

Related coverage:

U.S. allows emergency use of the drug remdesivir for virus treatment

Medical workers face severe equipment shortages amid virus spread

Online vegan cooking classes getting pandemic cut-through