A Study of S-268019 for the Prevention of COVID-19

NCT05212948 | Completed Phase 3 Results

• 1 other identifier: 2126U0232
• Study Type: interventional
• Target: 9,902
• Locations: 1 country
• Sites: 1

Brief Summary

The main purpose of this study is to assess the efficacy of S-268019-b for the prevention of COVID-19 in the initial vaccination period prior to crossover in participants without evidence of infection before vaccination as compared to placebo.

Conditions

SARS-CoV-2

Outcome Measures

Primary Outcomes (1)

• Number of Participants With First Occurrence of SARS-CoV-2 Reverse Transcription Polymerase Chain Reaction (RT-PCR)-Positive Symptomatic COVID-19 With Onset at Least 14 Days Following Second Vaccination During the Initial Vaccination Period

  Participants without evidence of infection before vaccination (that is, seronegative and PCR-negative at baseline) were determined to have symptomatic COVID-19 when at least 1 protocol-specified COVID-19-related symptom and a positive RT-PCR test result were confirmed by the medical monitor within at least 14 days following the second vaccination. RT-PCR testing was based upon nasopharyngeal swab sampling at protocol-specified timepoints.

  From Day 43 (14 days after the second dose administration) to Day 224

Secondary Outcomes (16)

• Number of Participants With First Occurrence of SARS-CoV-2 RT-PCR-Positive Severe COVID-19 in the Initial Vaccination Period With Onset at Least 14 Days Following Second Vaccination

  From Day 43 (14 days after the second dose administration) to Day 224

• Number of Participants With First Occurrence of SARS-CoV-2 RT-PCR-Positive Symptomatic COVID-19 in the Initial Vaccination Period

  Up to Day 224

• Number of Participants With First Occurrence of SARS-CoV-2 RT-PCR-Positive Severe COVID-19 in the Initial Vaccination Period

  Up to Day 224

• Number of Participants With First Occurrence of SARS-CoV-2 RT-PCR-Positive Symptomatic COVID-19 in the Initial Vaccination Period Regardless of Serostatus or PCR Status at Baseline With Onset at Least 14 Days Following Second Vaccination

  From Day 43 (14 days after the second dose administration) to Day 224

• Number of Participants With First Occurrence of SARS-CoV-2 RT-PCR-Positive Severe COVID-19 in the Initial Vaccination Period With Onset at Least 14 Days Following Second Vaccination Regardless of Serostatus or PCR Status at Baseline

  From Day 43 (14 days after the second dose administration) to Day 224

Study Arms (2)

S-268019-b, Then Placebo

EXPERIMENTAL

Participants will first receive a dose of S-268019-b via intramuscular (IM) injection on Day 1 and Day 29 during the initial vaccination period. After the initial vaccination period, participants will then receive a placebo IM injection (matching S-268019-b) on Day 225 and Day 253.

Drug: S-268019-b; Drug: Placebo

Placebo, Then S-268019-b

EXPERIMENTAL

Participants will first receive a dose of placebo IM injection (matching S-268019-b) on Day 1 and Day 29 during the initial vaccination period. After the initial vaccination period, participants will then receive S-268019-b IM injection on Day 225 and Day 253.

Drug: S-268019-b; Drug: Placebo

Interventions

S-268019-b DRUG

Solution for IM injection

Placebo, Then S-268019-b; S-268019-b, Then Placebo

Placebo DRUG

Saline solution for IM injection

Placebo, Then S-268019-b; S-268019-b, Then Placebo

Eligibility Criteria

• Age: 18 Years+
• Sex: all
• Healthy Volunteers: Yes
• Age Groups: Adult (18-64), Older Adult (65+)

You may qualify if:

• Agree not to participate in any other SARS-CoV-2 prevention trial during the study follow-up.
• Capable of using Diary without difficulties (if applicable, with assistance by caregiver).

You may not qualify if:

• Current or history of a laboratory-confirmed diagnosis of SARS-CoV-2 infection or COVID-19.
• Unstable current cardiovascular, respiratory, hepatic, renal, gastrointestinal, endocrine, hematological, or neurological disease that, in the opinion of the investigator or subinvestigator, would constitute a safety concern or confound data interpretation.
• Immunosuppression (immunodeficiency, acquired immunodeficiency syndrome \[AIDS\], use of systemic steroids, use of immunosuppressants within the past 6 months prior to the first dose of study intervention, treatment for malignant tumors, other immunosuppressive therapy).
• Previous vaccination against SARS-CoV-2.
• Any inactivated vaccine received within 14 days prior to the first dose of study intervention.
• Any live vaccine received within 28 days prior to the first dose of study intervention.
• Immunoglobulin preparations, blood products, or a blood transfusion within 3 months prior to the first dose of study intervention.

Sponsors & Collaborators

• Shionogi: lead

Study Sites (1)

Buon Ma Thuot City Medical Center

Buon Ma Thuot, Dak Lak, Vietnam

Location

Related Publications (1)

• Dinh Thiem V, Van Anh PT, Van Men C, Hung DT, Pollard AJ, Kamitani A, Tada Y, Fukuyama H, Iwasaki Y, Ariyasu M, Sonoyama T. A SARS-CoV-2 recombinant spike protein vaccine (S-268019-b) for COVID-19 prevention during the Omicron-dominant period: A phase 3, randomised, placebo-controlled clinical trial. Vaccine. 2024 Jun 20;42(17):3699-3709. doi: 10.1016/j.vaccine.2024.04.084. Epub 2024 May 10.

  PMID: 38734495 RESULT

MeSH Terms

Interventions

S-268019-b COVID-19 vaccine

Results Point of Contact

• Title: Shionogi Clinical Trials Administrator Clinical Support Help Line
• Organization: Shionogi

Shionogiclintrials-admin@shionogi.co.jp

1-800-849-9707

Publication Agreements

• PI is Sponsor Employee: No
• Restriction Type: OTHER
• Restrictive Agreement: Yes

Study Design

• Study Type: interventional
• Phase: phase 3
• Allocation: RANDOMIZED
• Masking: TRIPLE
• Who Masked: PARTICIPANT, CARE PROVIDER, INVESTIGATOR
• Purpose: PREVENTION
• Intervention Model: CROSSOVER
• Sponsor Type: INDUSTRY
• Responsible Party: SPONSOR

Study Record Dates

• First Submitted: January 24, 2022
• First Posted: January 28, 2022
• Study Start: December 25, 2021
• Primary Completion: December 19, 2022
• Study Completion: July 19, 2023
• Last Updated: November 28, 2025
• Results First Posted: November 28, 2025

Record last verified: 2025-11

Locations

VN (1)