Shionogi's COVID-19 antiviral nabs Japanese approval to rival drugs from Pfizer, Merck

As the fight against COVID-19 rolls on, regulators in Japan have bestowed a green light on the country's first homegrown antiviral.

The win goes to local drugmaker Shionogi, which has clinched an emergency approval for its oral antiviral Xocova from Japan’s Ministry of Health, Labour and Welfare (MHLW) to treat SARS-CoV-2 infection. The nod triggers a supply contract for the Japanese government to buy 1 million Xocova courses from Shionogi, the company said in a release.

Shionogi’s win marks the first green light for a drug under Japan’s new emergency regulatory approval system, the company added. Shionogi is also angling for approval of its antiviral pill in the United States.

In Japan, Shionogi originally filed for emergency approval of its drug in February. Then in July, the local health ministry said it needed to see results from a larger trial because the company’s original data didn’t show enough improvement in COVID-19 symptoms.

Xocova’s new Japanese approval is based on results from both mid- and late-stage components of Shionogi’s phase 2/3 antiviral study in Asia.

In the drug’s latest data drop from September, Xocova helped curb five typical Omicron-related COVID-19 symptoms (stuffy or runny nose, sore throat, cough, feeling hot or feverish, and low energy or tiredness) 24 hours faster than placebo. Shionigi’s pill is taken once a day for five days.

With an emergency approval in the books, Shionogi says it’s making effective Xocova distribution a priority. Meanwhile, the company will continue to pursue a standard approval for its drug in Japan, Shionogi added.

But the drug will have some Big Pharma competition. Merck's antiviral Lagevrio bagged a Japanese emergency nod last Christmas Eve, while Pfizer's Paxlovid won an authorization in February.

In October, meanwhile, Shionogi’s Japanese compatriot Fujifilm announced it was throwing in the towel on development of its own antiviral Avigan, also known as favipriavir, to treat COVID-19. In a recent release, Fujifilm explained it had stopped enrollment in a phase 3 Avigan COVID-19 trail in March following a “change of circumstances,” which included improved vaccination rates and the spread of Omicron variants.