Immunogenicity and Safety Study of SCB-2023 Vaccine as a Booster in Adults

Phase 3, Multi-center, Observer-blind, Randomized, Controlled Study to Evaluate the Immunogenicity and Safety of SCB-2023 Vaccine Administered as a Booster Dose to Adults Who Previously Received COVID-19 Vaccine

The purpose of this study is to assess the immunogenicity and safety of SCB-2023 trivalent vaccine compared to the prototype SCB-2019 monovalent vaccine in participants previously vaccinated with 3 doses of inactivated COVID-19 vaccine ≥6 months prior to enrollment.

Study Overview

• Status: Withdrawn
• Conditions: COVID-19
• Intervention / Treatment: Biological: SCB-2023 vaccine (trivalent), a recombinant SARS-CoV-2 trimeric S-protein subunit vaccine for COVID-19; intramuscular injection; Biological: SCB-2019 (monovalent), a recombinant SARS-CoV-2 trimeric S-protein subunit vaccine for COVID-19; intramuscular injection

• Study Type: Interventional
• Phase: Phase 3

Contacts and Locations

Study Locations

• Philippines
  • Manila, Philippines
    • Manila Doctors Hospital
  • Manila, Philippines
    • Health Index Multispecialty Clinic
  • Putatan, Philippines
    • Tropical Disease Foundation

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: Adult; Older Adult
• Accepts Healthy Volunteers: Yes

Description

Inclusion Criteria:

• Male or female ≥18 years of age.
• Individuals willing and able to comply with study requirements, including all scheduled visits, vaccinations, laboratory tests and other study procedures.
• Individuals willing and able to give an informed consent, prior to screening.
• Healthy participants or participants with pre-existing medical conditions who are in a stable medical condition.
• Individuals who received three doses of inactivated COVID-19 vaccine.

Exclusion Criteria:

• Body temperature >37.8°C (axillary), or any acute illness at baseline.
• Confirmed SARS-CoV-2 infectionor with known history of COVID-19.
• Individuals who have received an investigational or licensed COVID-19 vaccine prior to Day 1 (except for inactivated COVID-19 vaccine).
• Any confirmed or suspected immunosuppressive or immunodeficient condition resulting from disease or immunosuppressive/cytotoxic therapy.
• Any progressive unstable or uncontrolled clinical conditions.
• Individuals who are pregnant, or breastfeeding, or planning to become pregnant while enrolled in this study or during the study period.
• History of severe adverse reaction associated with a vaccine or severe allergic reaction.
• History of malignancy within 1 year before screening.
• Individuals who have received any other investigational product.
• Individuals who have received any other licensed vaccines within 14 days prior to enrollment.
• Treatment with Rituximab or any other anti-CD20 monoclonal antibodies.
• Known bleeding disorder that would, in the opinion of the investigator, contraindicate i.m. injection.
• Administration of intravenous immunoglobulins and/or any blood products.
• Any condition that, in the opinion of the investigator, would interfere with the primary study objectives or pose additional risk to the participant.

Study Plan

How is the study designed?

Design Details

• Primary Purpose: Prevention
• Allocation: Randomized
• Interventional Model: Parallel Assignment
• Masking: Quadruple

Number of Arms

2

Arms and Interventions

Participant Group / Arm	Intervention / Treatment
Experimental: SCB-2023 arm; Participants will receive one booster dose with SCB-2023 vaccine on Day 1	Biological: SCB-2023 vaccine (trivalent), a recombinant SARS-CoV-2 trimeric S-protein subunit vaccine for COVID-19; intramuscular injection; SCB-2023 vaccine (trivalent), a recombinant SARS-CoV-2 trimeric S-protein subunit vaccine for COVID-19; intramuscular injection
Active Comparator: SCB-2019 arm; Participants will receive one booster dose with SCB-2019 vaccine on Day 1	Biological: SCB-2019 (monovalent), a recombinant SARS-CoV-2 trimeric S-protein subunit vaccine for COVID-19; intramuscular injection; SCB-2019 (monovalent), a recombinant SARS-CoV-2 trimeric S-protein subunit vaccine for COVID-19; intramuscular injection

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
To demonstrate that SCB-2023 vaccine elicits an immune response superior to SCB-2019 for Omicron BA.5	GMT ratio	Day 15
To demonstrate that SCB-2023 vaccine elicits an immune response superior to SCB-2019 for Omicron XBB.1.5	GMT ratio	Day 15
Assess the reactogenicity of SCB-2023 vaccine compared to SCB-2019 vaccine	Proportion of participants with local and systemic AEs	Day 7
Assess the safety of SCB-2023 vaccine compared to SCB-2019 vaccine	Proportion of participants with unsolicited AEs	Day 29
Assess the safety of SCB-2023 vaccine compared to SCB-2019 vaccine	Proportion of participants with SAE, AEs leading to early termination from study, MAAEs, and AESIs	Up to 1 year post-vaccination

Secondary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Non-inferiority with respect to ratio of the geometric mean of Omicron BA.5 titer in SCB-2023 recipients and SARS-CoV-2 Delta titers in SCB-2019 recipients, as measured by virus neutralization assay.	GMT ratio	Day 15
Geometric mean titers elicited by SCB-2023 vaccine and SCB-2019 vaccine by virus neutralization assay against Omicron BA.5 and Omicron XBB1.5.	GMTs; GMFRs; SCRs; Proportion of participants with antibody titer ≥ LLoQ	Day 1, 15, 180
Geometric mean fold rise elicited by SCB-2023 vaccine and SCB-2019 vaccines by virus neutralization assay against Omicron BA.5 and Omicron XBB1.5	GMFRs	Day 1, 15, 180
Proportion of subjects with seroconversion by virus neutralization assay against Omicron BA.5 and Omicron XBB1.5	SCRs	Day 1, 15, 180
Proportion of subjects with antibody titer >=LLOQ by virus neutralization assay against Omicron BA.5 and Omicron XBB1.5	Proportion of participants with antibody titer ≥ LLoQ	Day 1, 15, 180
Geometric mean titers elicited by SCB-2023 vaccine and SCB-2019 vaccine by virus neutralization assay against SARS-CoV-2 variants of concern	GMTs	Day 1, 15
Geometric mean fold rise elicited by SCB-2023 vaccine and SCB-2019 vaccines by virus neutralization assay against SARS-CoV-2 variants of concern	GMFRs	Day 1, 15
Proportion of subjects with seroconversion by virus neutralization assay against SARS-CoV-2 variants of concern	SCRs	Day 1, 15
Proportion of subjects with antibody titer >=LLOQ by virus neutralization assay against SARS-CoV-2 variants of concern	Proportion of participants with antibody titer ≥ LLoQ	Day 1, 15

Collaborators and Investigators

• Sponsor: Clover Biopharmaceuticals AUS Pty Ltd

Study record dates

Study Major Dates

• Study Start (Actual): August 17, 2023
• Primary Completion (Actual): August 17, 2023
• Study Completion (Actual): August 17, 2023

Study Registration Dates

• First Submitted: June 8, 2023
• First Submitted That Met QC Criteria: June 21, 2023
• First Posted (Actual): July 3, 2023

Study Record Updates

• Last Update Posted (Actual): August 25, 2023
• Last Update Submitted That Met QC Criteria: August 23, 2023
• Last Verified: August 1, 2023

More Information

Terms related to this study

• Additional Relevant MeSH Terms: Coronavirus Infections; Coronaviridae Infections; Nidovirales Infections; RNA Virus Infections; Virus Diseases; Infections; Respiratory Tract Infections; Respiratory Tract Diseases; Pneumonia, Viral; Pneumonia; Lung Diseases; COVID-19; Physiological Effects of Drugs; Molecular Mechanisms of Pharmacological Action; Enzyme Inhibitors; Immunologic Factors; Protease Inhibitors; Serine Proteinase Inhibitors; Trypsin Inhibitors; Vaccines; Somatomedin B
• Other Study ID Numbers: CLO-SCB-2023-002

Drug and device information, study documents

• Studies a U.S. FDA-regulated drug product: No
• Studies a U.S. FDA-regulated device product: No