Shionogi & Co., Ltd. announced that its partner Ildong Pharmaceutical Co., Ltd. (Head Office: Seoul, South Korea; Vice Chairman and Chief Executive Officer: Yun Paul Woongsup, hereafter "Ildong") who has been sub-Licensed South Korean rights to Ensitrelvir Fumaric Acid (development number: S-217622, hereafter "ensitrelvir"), has filed a New Drug Application (NDA) with the MFDS (Ministry of Food and Drug Safety) for the indication of SARS-CoV-2 infection, and this application has been accepted for review by MFDS. Following the approval of ensitrelvir in Japan on November 22, 2022, which was based on the data from the Asian Phase 2/3 clinical trials that SHIONOGI have been conducting, mainly in Japan, Ildong has been in discussions with the MFDS and the Korean Disease Control and Prevention Agency (KDCA) in order to obtain approval in South Korea. Accordingly, Ildong has now submitted a conditional approval application to MFDS on January 3, 2023, which was accepted for review.

Shionogi group will continue to work closely with Ildong to provide the necessary support for approval and commercial launch in South Korea. Ensitrelvir (Code No.: S-217622), an antiviral drug for COVID-19 currently approved under the emergency regulatory approval system in Japan, is a 3CL protease inhibitor created through joint research between Hokkaido University and Shionogi. SARS-CoV-2 has an enzyme called 3CL protease, which is essential for the replication of the virus.

Ensitrelvir suppresses the replication of SARS-CoV-2 by selectively inhibiting 3CL protease. Ensitrelvir is the first antiviral agent to show both clinical symptomatic efficacy for five typical Omicron-related symptoms (primary endpoint) and antiviral efficacy (key secondary endpoint) in patients with mild to moderate SARS-CoV-2 infection, regardless of risk factors or vaccination status, in the Phase 3 part of the Phase 2/3 study conducted during the Omicron-dominant phase of the epidemic. Currently, the Phase 2b/3 part of the Phase 2/3 study targeting SARS-CoV-2 infected persons with asymptomatic/mild symptoms only is being conducted in Asia, mainly in Japan.

With regard to safety, ensitrelvir was well tolerated, and there were no treatment-related serious adverse events or deaths in the study. The most common treatment-related adverse events were transient decreases in high-density lipoprotein and increases in blood triglycerides, as observed in previous studies. A global Phase 3 trial (SCORPIO-HR study) in non-hospitalized SARS-CoV-2 infected patients is ongoing.

In addition, a global Phase 3 trial (STRIVE study) for hospitalized SARS-CoV-2 infected patients is scheduled to initiate soon. An onset prevention study for household members living with SARS-CoV-2 infected individuals and a pediatric study for children under the age of 12 are also in preparation.