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Evaluating a new protease inhibitor for COVID-19 treatment

Strategies and Treatments for Respiratory Infections & Viral Emergencies (STRIVE): Shionogi Protease Inhibitor

Phase 3 Interventional University of Minnesota · NCT05605093

This study is testing a new antiviral drug for COVID-19 to see if it can help hospitalized patients feel better when added to their usual treatment.

Quick facts

PhasePhase 3
Study typeInterventional
Enrollment1500 (estimated)
Ages18 Years and up
SexAll
SponsorUniversity of Minnesota Academic / other
Locations186 sites (Birmingham, Alabama and 185 other locations)
Trial IDNCT05605093 on ClinicalTrials.gov

What this trial studies

This clinical trial assesses the efficacy of S-217622 (ensitrelvir), a protease inhibitor developed by Shionogi, in hospitalized patients with COVID-19. It is a randomized, placebo-controlled, multi-center international trial that aims to improve patient outcomes by adding this antiviral treatment to the standard of care. Participants will be monitored for clinical improvements while receiving either the active drug or a placebo, alongside existing treatment protocols for COVID-19.

Who should consider this trial

Good fit: Ideal candidates are adults aged 18 and older who are hospitalized with confirmed SARS-CoV2 infection and exhibit symptoms of respiratory infection.

Not a fit: Patients who are expected to be discharged within 24 hours or have severe comorbid conditions likely to result in death within a week may not benefit from this study.

Why it matters

Potential benefit: If successful, this treatment could significantly improve recovery rates and outcomes for hospitalized COVID-19 patients.

How similar studies have performed: Other studies evaluating antiviral treatments for COVID-19 have shown promise, suggesting that this approach may be effective.

Eligibility criteria

Show full inclusion / exclusion criteria 
Inclusion Criteria:

* Age ≥18 years.
* Informed consent for trial participation.
* Hospital admission (or boarding in an emergency department or other area awaiting hospital admission) with signs and/or symptoms of a respiratory infection.
* Confirmation of SARS-CoV2 infection by nucleic acid test (NAT) or equivalent non- NAT test \[list of approved tests is in the PIM\] collected within the prior 14 days.
* Onset of symptoms attributable to SARS-CoV2 infection occurred within 14 days before randomization.
* Hospitalized for the management of COVID-19, with signs and/or symptoms suggestive of lower respiratory tract infection.

Exclusion Criteria:

* The patient is expected to be discharged from the hospital within the next 24 hours.
* Medical condition other than the acute respiratory infection (and its manifestations) that is likely to result in death within 7 days of randomization.
* Use of a strong CYP3A inducer within 14 days prior to enrollment
* Moribund condition, defined as prior cardiac arrest during this hospitalization and life expectancy less than 48 hours of randomization.
* Patient undergoing comfort care measures only such that treatment focuses on end-of- life symptom management over prolongation of life.
* Expected inability or unwillingness to participate in study procedures.
* In the opinion of the investigator, participation in a trial is not in the best interest of the patient.
* Allergy to investigational agent or vehicle
* Use of a concomitant medication that is contraindicated due to a drug-drug interaction with S-217622
* Moderate to severe hepatic impairment (i.e., Child-Pugh class B or C) or acute liver failure.
* Known estimated glomerular filtration rate (eGRF) \<30 mL/min/1.73m 2
* Continuous renal replacement therapy or chronic dialysis
* Current pregnancy
* Current breastfeeding and unwillingness to defer breastfeeding for 30 days after the last dose of investigational agent.
* Women of child-bearing potential who are unwilling to abstain from sexual intercourse with men or practice appropriate contraception through 30 days from the last dose of the investigational agent.
* Men who are unwilling to abstain from sexual intercourse with women of child- bearing potential or to use barrier contraception through 30 days from the last dose of the investigational agent.
* Inability to take investigational agent in tablet form by mouth.

Where this trial is running

Birmingham, Alabama and 185 other locations

+136 more sites — see ClinicalTrials.gov for the full list.

Study contacts

How to participate

  1. Review the eligibility criteria above with your treating physician.
  2. Visit the official trial page on ClinicalTrials.gov for the most current contact information and recruitment status.
  3. Contact the listed study coordinator or principal investigator to request pre-screening. Pre-screening is free and never obligates you to enroll.
View on ClinicalTrials.gov → Find more trials like this →
Conditions COVID-19
Last reviewed 2026-06-13 by the Find a Trial editorial team. Information on this page is for educational purposes and is not medical advice. Always consult qualified healthcare professionals about clinical trial participation.