Candidate: S-217622 


Type: 3CL protease inhibitor created through joint research between Hokkaido University and Shionogi. S-217622 is designed to suppress the replication of SARS-CoV-2 by selectively inhibiting 3CL protease.  

2022 Status: FDA Clears Phase III Trial—Shionogi said March 16 that the FDA had cleared the IND application for S-217622, enabling the global Phase III SCORPIO-HR (also known as ACTIV-2d) to proceed. SCORPIO-HR is designed to evaluate the safety and efficacy of S-217622 as a once-daily oral treatment for high-risk, non-hospitalized adults with COVID-19 within five days of symptom onset. The trial is being conducted by the AIDS Clinical Trials Group (ACTG), sponsored by Shionogi, and funded by the NIH’s National Institute of Allergy and Infectious Diseases (NIAID).

SCORPIO-HR will be conducted with trial sites in countries in Europe, South America, North America, Africa, and Asia. Approximately 1,700 participants will be randomized in a 2:1 ratio such that two thirds receive S-217622 and one third receive placebo. Participants may take locally provided COVID-19 treatment after enrollment, as long as it is compatible with S-217622, Shionogi said.

SCORPIO-HR follows supportive, positive results from Phase IIa and Phase IIb clinical trials (primarily conducted in Japan and used for submission to the Japanese health authority) that demonstrated proof of concept with significant antiviral activity and rapid cessation of infectious virus shedding.

S-217622 Shows Safety in Phase I Trial—Shionogi said October 21 that S-217622 showed itself to be safe and well tolerated in a Japanese Phase I trial, a single ascending dose study to healthy Japanese subjects. The once-daily oral dosing of S-217622 was predicted to exceed the target concentration required for the viral reduction effect from the non-clinical studies, Shionogi said.  

The company also reported results from non-clinical studies in which S-217622 showed in vitro antiviral activity against a broad range of strains, including the Delta strain. A dose-dependent viral reduction effect of S-217622 was seen in multiple animal studies, while S-217622 showed a good drug metabolism and pharmacokinetics profile supporting oral dosing, the company said without furnishing details. 

Based on these results, S-217622 has the potential to reduce SARS-CoV-2 viral load with once-daily oral administration,” the company stated.

COVID-19: 300 Candidates and Counting

To navigate through the >300 potential therapeutic and vaccine options for COVID-19, GEN has grouped the candidates into four broad categories based on their developmental and (where applicable) clinical progress:

FRONT RUNNER – the most promising therapeutics/vaccines based on clinical progress, favorable data or both.

DEFINITELY MAYBE – earlier phases with promising partners, or more advanced candidates in development that have generated uneven data.

KEEPING AN EYE ON… – interesting technology, attracting notable partners, or both, but preliminary data.

TOO SOON TO TELL – longshots pending additional experimental and/or clinical data.

GEN has also tagged the most common treatment types:


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