Phase II/III clinical trial results (phase IIa part) for the COVID-19 therapeutic drug S-217622.

During the presentation, in addition to results from secondary analyses of the antiviral effect, which is the primary endpoint of the Phase IIa part of the Phase II/III clinical trial, symptom improvement, exacerbation prevention, and safety results were newly disclosed. This study is a randomized, placebo-controlled, double-blind study in Japanese adults, in which the efficacy and safety of this drug given orally once daily for 5 days was evaluated.

Antiviral effect: The S 217622 arms showed a significant difference in comparison to placebo with respect to each of the following:- Rapid reductions in viral titer and viral RNA. - On day 4 (after the 3rd dose), the proportion of subjects with positive viral titer decreased by approximately 60-80%, compared to the placebo group. - Median time to the negative SARS-CoV-2 viral titer shortened by 2 days compared to the placebo group.

Clinical symptom improvement; S 217622 showed a tendency toward improvement in total score of 12 COVID-19 symptoms. No cases of exacerbation required hospitalization or similar therapy as hospitalization were found in the S 217622 group.

Safety: - No high-grade or serious adverse events have been observed. - No adverse events resulting in discontinuation have been observed. - Almost all TEAE were mild and all treatment-related TEAE were mild.

As expressed in the related notifications, Shionogi plans to submit these clinical data to the Pharmaceuticals and Medical Devices Agency (PMDA) in the near future. Furthermore, for subjects with mild/moderate SARS-CoV-2 infection, we plan to complete enrollment of the Phase IIb part on February 8 2022 and initiate the Phase III part in the near future. We will continue to consult closely with the Ministry of Health, Labor and Welfare, PMDA and other organizations regarding future steps in the submission process.