A Phase 2/3, Randomized, Active-controlled, Observer-blinded, Non-inferiority Study to Evaluate the Safety and Immunogenicity of Booster Immunization with DS-5670a/b (Bivalent: Original Strain/Omicron Strain BA.4-5) in Subjects Aged 5 to 11 Years Who Have Completed Initial Immunization with Comirnaty Intramuscular Injection (Univalent: Original Strain)

Status

Active, not recruiting

Phases

Phase 3

Study type

Interventional

Source

JPRN

Registry ID

JPRN-jRCT2031220665

Enrollment

210

Registered

2023-02-28

Start date

2023-05-27

Completion date

Unknown

Last updated

2026-06-29

For informational purposes only — not medical advice. Sourced from public registries and may not reflect the latest updates. Terms

Conditions

Prevention of infectious disease by Severe acute respiratory syndrome coronavirus 2(SARS-CoV-2)

Interventions

A dose of either DS-5670a/b or Comirnaty IM will be intramuscularly administered to the deltoid muscle of the upper arm.

Eligibility

Sex/Gender

All

Inclusion criteria

Inclusion criteria: 1) Subjects aged 5 to 11 years at the time of informed consent. 2) Having provided written consent to study participation via the legal representative. 3)Having completed initial immunization with Comirnaty IM in the past, with at least 3 months elapsed since the 2nd dose. 4) Able to comply with the rules of the study, undergo physical examinations and tests that are specified in the protocol, and report symptoms or other issues.

Exclusion criteria

Exclusion criteria: 1) Having any serious cardiovascular, renal, hepatic, blood, neuropsychiatric, developmental disorder, thrombocytopenia, or coagulopathy. 2) Having a medical history of vaccination-related convulsions or epilepsy. 3) Having a concurrent or medical history of myocarditis or pericarditis. 4) Having tested positive for SARS-CoV-2 infection (based on reverse transcription polymerase chain reaction [RT-PCR], other nucleic acid detection methods, or SARS-CoV-2 antigen test) within 3 months before informed consent, or having been diagnosed with coronavirus disease 2019 (COVID-19) based on a physician's examination. 5) Having been diagnosed with immunodeficiency in the past or having a close relative with congenital immunodeficiency. 6) Having symptoms suspected of SARS-CoV-2 infection (eg, respiratory symptoms, headache, malaise, anosmia, dysgeusia, pharyngeal pain) at the time of informed consent 7) Having tested positive for SARS-CoV-2 antibody test at the time of eligibility evaluation, with symptoms suspected of SARS-CoV-2 infection (eg, respiratory symptoms, headache, malaise, anosmia, dysgeusia, pharyngeal pain) within 3 months before informed consent.

Design outcomes

Primary

Measure	Time frame
GMT of blood neutralizing activity against SARS-CoV-2 (Omicron strain BA.5) and seroresponse rate at 4 weeks after study drug administration	—

Secondary

Measure	Time frame
Efficacy - GMT of blood neutralizing activity against SARS-CoV-2 (original strain) and seroresponse rate at 4 weeks after study drug administration - Incidence of COVID-19 for 52 weeks after study drug administration Safety Solicited adverse events (injection site and systemic), Unsolicited adverse events, Serious adverse events, Laboratory values for 28 days after study drug administration	—

Contacts

Public ContactContact for Clinical Trial Information

DAIICHI SANKYO Co.,Ltd.

dsclinicaltrial_jp@daiichisankyo.com+81-3-6225-1111

Outcome results

None listed

Source: JPRN (via WHO ICTRP) · Data processed: Jul 3, 2026