Shionogi & Co., Ltd. announced that ensitrelvir fumaric acid (S-217622), Shionogi's orally administered antiviral drug for COVID-19 (caused by infection with the novel coronavirus (SARS-CoV- 2)), shows high in vitro antiviral activity against the Omicron subvariant (BA.2.75), with antiviral potency in preclinical testing similar to its potency against other existing variants. As of August 2022, the SARS-CoV-2 Omicron BA.2.75 subvariant has been detected in Japan1. There is limited data at this time as to the spread of infection and severity of the BA.2.75 subvariant compared to other variants, but all monoclonal antibody anti-coronavirus therapeutics listed in the report2 are ineffective against it and some vaccines may be less protective, due to spike protein mutations.".

Shionogi will continue to closely monitor the trends of infection and, in parallel, accumulate evidence for S-217622. The company will also continually evaluate S-217622's potency against newly arising mutant strains as soon as clinical isolates are available, and thereby to provide information which can be beneficial for public health.