TOKYO (Reuters) – Japan’s Shionogi & Co said on Tuesday a global, late-stage study showed its pill-based treatment for COVID-19 was effective in reducing transmission of the disease.

Ensitrelvir, known commercially as Xocova, showed a statistically significant reduction in participants with symptomatic infection after exposure to household contacts with COVID, Shionogi said in a statement.

The Phase 3 SCORPIO-PEP trial involved about 2,400 participants in the United States, South America, Africa, and Asia.

The result follows the drugmaker’s May comments that its SCORPIO-HR trial showed the pill failed to reduce common symptoms of the illness, compared to a placebo.

Japan gave the drug full approval in March this year. Although the government bought 2 million courses of the treatment during the pandemic, most of the supply was unused and set to be destroyed, media said.