Actively Recruiting
A 2-Stage, Phase I/II, Randomized Study to Assess Safety and Immune Response of SK Japanese Encephalitis mRNA Vaccines (GBP560) in Healthy Adults
Led by SK Bioscience Co., Ltd. · Updated on 2025-12-23
402
Participants Needed
3
Research Sites
90 weeks
Total Duration
On this page
AI-Summary
What this Trial Is About
Researchers are evaluating the safety, reactogenicity, and immune response of SK Japanese Encephalitis mRNA vaccines (GBP560) in healthy adults aged 18 years and older. This 2-stage, Phase I/II randomized and observer-blinded study compares different doses and formulations of GBP560 with active comparators IXIARO and IMOJEV. The purpose is to understand how the vaccines perform in terms of safety and immune protection against Japanese Encephalitis Virus (JEV). Participants receive two doses of the test vaccines or comparators at 4-week intervals. Stage 1 tests low, mid, and high doses (3, 15, and 50 micrograms) of GBP560 variants A and B. Active comparators IXIARO and IMOJEV, as well as placebo saline for IMOJEV, are also given in Stage 1 and Stage 2. In Stage 2, participants receive two intramuscular injections aligned with the selected dose regimen from Stage 1. Throughout the study, participants are monitored for immediate reactions, local and systemic side effects, and any adverse events up to 24 months after vaccination. Immune responses are measured using live-virus neutralization tests at multiple time points up to two years after the second dose. Additional assessments include cell-mediated immune responses. The study includes regular visits for vaccinations, safety checks, and blood tests to evaluate the vaccine's impact on immune protection and safety in healthy adults.
CONDITIONS
Brief Title
A Study to Assess the Safety, Reactogenicity, and Immunogenicity of SK Japanese Encephalitis Messenger Ribonucleic Acid (mRNA) Vaccines (GBP560) in Healthy Adults
Who Can Participate
Eligibility Criteria
You may qualify if you...
- For Stage 1, age 18 to 55 years inclusive at consent
- For Stage 2, age 18 years and older at consent
- Healthy as confirmed by medical evaluation including history, vital signs, physical exam, and lab tests
- Willing and able to attend all study visits and follow procedures
- Body mass index between 18.5 and 29.9 kg/m2 at screening
- Agree to be heterosexually inactive or use contraception from 4 weeks before first vaccination to 12 weeks after last vaccination
- Female participants must have a negative pregnancy test at screening unless surgically sterile or postmenopausal
- Able to provide signed informed consent and comply with study requirements
You will not qualify if you...
- Any significant respiratory symptoms, fever, or acute illness within 24 hours before first vaccination
- History of immunodeficiency, autoimmune disease, or congenital/hereditary immune disorders
- Positive test for hepatitis B, hepatitis C, or HIV at screening
- History of bleeding disorders or thrombocytopenia contraindicating intramuscular vaccination
- History of severe allergic reactions to vaccines or study components
- History of myocarditis, pericarditis, or related heart conditions
- Previous infection with Japanese Encephalitis Virus or other flaviviruses
- Malignancy within 1 year before first vaccination (except low-risk cases)
- Unstable chronic or acute illness that could interfere with safety or study results
- Other conditions that may affect study evaluation such as alcohol/drug abuse or neurological/psychiatric disorders
- Pregnant or breastfeeding females
- Current smokers or recent smokers within 12 weeks prior to screening (Stage 1 only)
- Prior vaccination against Japanese Encephalitis or other flaviviruses
- Any vaccine received within 4 weeks before first study vaccination except inactivated influenza vaccine given at least 2 weeks prior
- Receipt of immunoglobulins or blood products within 12 weeks prior to first vaccination
- Use of immunosuppressive therapy or systemic corticosteroids within 12 weeks prior to first vaccination
- Participation in another clinical trial with investigational product within 4 weeks prior to first vaccination or planned concurrent participation
- Investigators, study staff involved in this study, and their family members
- Blood donation of 450 mL or more within 4 weeks prior to screening or planned donation during study period
AI-Screening
AI-Powered Screening
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Your Study Journey
Duration - 2 to 4 weeks
Participants are screened for eligibility to participate in the trial.
1 visit (in-person)
Duration - 4 weeks
Participants receive two doses of one of the study vaccines or comparators by intramuscular injection at 4-week intervals.
2 vaccination visits (in-person) on Day 1 and Day 29
Duration - Up to 24 months
Participants are monitored for safety, immune response, and adverse events up to 24 months following the last vaccination.
Multiple follow-up visits over 24 months for safety and immune assessments
Trial Site Locations
Total: 3 locations
1
Nucleus Network - Brisbane (Q Pharm)
Brisbane, Australia
Actively Recruiting
2
Nucleus Network - Melbourne
Melbourne, Australia
Actively Recruiting
3
New Zealand Clinical Research
Christchurch, Central City, New Zealand, 8011
Not Yet Recruiting
Research Team
S
Sejun Oh
How is the study designed?
Study Type
INTERVENTIONAL
Masking
QUADRUPLE
Allocation
RANDOMIZED
Model
SEQUENTIAL
Primary Purpose
PREVENTION
Number of Arms
10
Frequently Asked Questions
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