Shionogi & Co.’s experimental COVID-19 treatment Xocova failed to win the backing of health experts in Japan who said there wasn’t enough data to show the medicine’s efficacy.

The panel members didn’t recommend that Japan’s health ministry authorize emergency use of the therapy as there was a need to continue discussion on it, Hiroshi Kiyota, chairman of the expert committee said in a briefing Wednesday. The health ministry relies on the panel’s decision to give the approval.

Japan so far has two pills to fight coronavirus and Shionogi’s therapy was seeking to be the third option. Approval for Shionogi’s medicine was keenly watched as it is easier to take than the two currently available drugs from U.S. drugmakers. A course of Shionogi treatment consists of seven pills over five days — significantly fewer than Pfizer’s Paxlovid and Merck & Co.’s Lagevrio, which require between 30 pills and 40 pills over the same time period.

The panel decided that it will continue discussion on Xocova and await submission of Phase 3 trial data which is expected in November, according to a representative from Pharmaceutical and Medical Devices Agency, Japan’s drug regulator.

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This stretches the wait for a domestic supply of an antiviral medicine in Japan that can help avert hospitalizations and deaths from COVID-19. COVID pills are becoming a crucial disease-fighting tool as the world transitions to living with the virus. Japan, already one of the oldest nations in the world, has also achieved one of the lowest death rates of the pandemic.


This was Xocova’s second panel review, as required for full transparency under the existing rules for the emergency authorization process, according to Japan’s health minister Shigeyuki Goto. The company’s shares fell 5.6% after the first meeting in June which had a similar outcome when experts postponed their decision and said additional “careful discussion” was needed.

Japan’s government agreed in March to buy 1 million courses of the drug immediately after approval. The Osaka-based company, which already can make enough to treat 1 million people annually, says it plans to eventually produce enough supply for 10 million patients a year.

Shionogi’s easier-to-take pill has the potential to generate $2 billion in annual sales, Chief Executive Officer Isao Teshirogi said in October. The company partnered with the AIDS Clinical Trial Group in March to run studies needed to get U.S. approval.

The medicine is a protease inhibitor that works like Pfizer’s Paxlovid, and targets a different part of the virus replication process than Merck’s Lagevrio. It’s possible it could be given in combination with Merck’s treatment, something the companies have discussed, Teshirogi said.

The drugmaker is also seeking opportunities to sell the medicine in other parts of the world. It’s running a phase three trial in the U.S. with the AIDS Clinical Trials Group, and has begun submitting data to regulators in China with its partner Ping An Life Insurance Company of China Ltd.