Japan's Shionogi says COVID treatment did not meet endpoint in late-stage trial

The logo of Shionogi & Co Ltd is displayed at their Tokyo branch office in Tokyo

TOKYO (Reuters) - Japan's Shionogi & Co said on Monday its pill-based treatment for COVID-19 did not meet the primary endpoint of showing a statistically significant reduction of 15 common symptoms of the illness in a global, late-stage trial.

The company's pivotal Phase 3 study (SCORPIO-HR) of ensitrelvir did however demonstrate a potent antiviral effect compared to placebo, the company said.


Shionogi said previously it expected the pill, known commercially as Xocova, to deliver $2 billion in annual sales if it secured U.S. approval.

Xocova would compete with Pfizer's antiviral drug Paxlovid.

Shionogi's CEO told the Nikkei newspaper in March that the company expected to be able to sell the drug in the U.S. in early 2025.


Xocova was granted emergency approval by Japanese regulators in November 2022, making it the nation's first domestically produced oral treatment for COVID. It received full approval in Japan in March 2024.

The Japanese government bought 2 million courses of the drug, most of which remain unused and are set to be destroyed, according to a Kyodo report this month.

The drug was granted Fast Track designation by the U.S. Food and Drug Administration in 2023.

The SCORPIO-HR trial is a part of the U.S. National Institutes of Health's (NIH) public-private partnership for COVID treatments and vaccines.


The company said it will continue working with regulatory bodies to explore routes to making ensitrelvir available, without giving further details.

(Editing by Jan Harvey)