TOKYO — Japanese drugmaker Shionogi said Monday that preliminary laboratory studies suggest its COVID-19 tablet inhibits the severity of infections from the highly transmissible omicron variant, providing optimism that the low-cost treatment may help prevent a surge in hospitalizations.
The antiviral pill for people at the early stage of infection is designed to prevent severe illness and reduce symptoms such as fever and cough. The tablet blocks the function of an enzyme called a protease, slowing the spread of the virus.
Shionogi’s preliminary data “confirmed that S-217622, an oral antiviral drug that selectively inhibits 3CL protease, exhibits high antiviral activity against the omicron variant” as it does with other strains, the company said in a statement.
Clinical trials with asymptomatic or mildly ill people began in late September and are in the final phase. The company plans to apply for Japanese approval this month.
The data comes from lab studies using omicron samples Shionogi received from Japan’s National Institute of Infectious Diseases this month.
Shionogi is also developing a COVID-19 vaccine and building a system to test it against the omicron variant. In the event existing vaccines lose efficacy, the company has also finished the antigen design of the vaccine against the omicron.
Shionogi’s news follows Pfizer’s application for U.S. authorization of Paxlovid, a therapy consisting of two types of pills for those with mild to moderate symptoms. On Dec. 14, the U.S. company reported an initial analysis indicating that one type, nirmatrelvir, “potently inhibited the 3CL protease associated with omicron” in lab studies. Pfizer has agreed to supply Japan with 2 million doses of the antiviral treatment.
Merck’s pill, molnupiravir, won U.K. approval in November, and an application for Japanese authorization covering manufacturing and sales was filed Dec. 3. The medication is expected to be effective regardless of mutations and likely would work against omicron, said a spokesperson at MSD, the Japanese arm of the U.S. drugmaker.