A Phase 1/2 interventional study of GBP560-A and GBP560-B in Japanese Encephalitis Virus Disease, sponsored by SK Bioscience Co., Ltd.. Completed at 3 sites in 2 countries. Open to participants aged 18 Years and older, including healthy volunteers. Per ClinicalTrials.gov, last updated 2026-09-11.
Sponsored by SK Bioscience Co., Ltd. (part of SK Chemicals Co., Ltd.) · Phase 1/2, Interventional, and Prevention
This is a 2-Stage, Phase I/II Study to Assess the Safety, Reactogenicity, and Immunogenicity of SK Japanese Encephalitis mRNA Vaccines (GBP560) in Healthy Adults (Aged 18 Years and Older)
The purpose of this study is to assess the safety, reactogenicity and immunogenicity of SK Japanese Encephalitis mRNA vaccines (GBP560) in healthy adults.
74 studies on the registry are indexed under Encephalitis, Japanese; 3 are open to participants now.
This study's enrollment of 161 is below the median of 300 across 65 interventional studies indexed under Encephalitis, Japanese.
Browse Encephalitis, Japanese studies →SK Bioscience Co., Ltd. is the lead sponsor of 12 studies on the registry; 1 is open to participants now.
Counted across the registry records on this site, refreshed daily.
Go through the criteria one by one — yes, no or not sure — and take the list to your doctor or the study team. Kept in this browser only.
[Age]
For Stage 1, participant must be 18 to 55 years of age inclusive, at the time of signing the .
For Stage 2, participant must be 18 years of age and older, at the time of signing the informed consent.
[Type of Participant and Disease Characteristics]
(BMI) within the range of 18.5-29.9 kg/m2 (inclusive) at screening
[Sex and /Barrier Requirements]
Female participants with a negative urine or serum pregnancy test at screening.
* Female participants who are surgically sterile (e.g., having undergone a full hysterectomy, bilateral salpingectomy, or bilateral oophorectomy) or with amenorrhea for at least 12 months are not subject to a pregnancy test.
[Informed Consent]
Exclusion Criteria:
[Medical Conditions]
Significant unstable chronic or acute illness that, in the opinion of the investigator, might pose a health risk to the participant if enrolled, or could interfere with the protocol-specified activities, or interpretation of study results.
* The AESIs as outlined in Section 8.1.4 should be considered for evaluating the participant
(Only for Stage 1) Current smoker or a recent smoking history within 12 weeks prior to screening. Occasional smoker who smokes up to 10 cigarettes per month may be allowed to participate at the investigator's discretion.
[Prior/Concomitant medication]
Receipt of therapy, such as any use of anti-cancer chemotherapy or radiation therapy; or systemic therapy (≥10 mg prednisone/day or equivalent) within 12 weeks prior to the 1st study vaccination. The use of inhaled, topical, or nasal glucocorticoid will be permitted.
[Prior/Concurrent Clinical Study Experience]
Participation in another clinical study and receipt of study intervention within 4 weeks prior to the 1st study vaccination, or concurrent, planned participation in another clinical study with study intervention during this study period.
[Other Exclusions]
Underlined terms in the criteria open these too. Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Before you join, the study team explains what taking part involves — its purpose, what happens, the risks and possible benefits — and answers your questions, so you can decide freely. Consent is usually recorded on a form (the informed consent form, ICF) signed by you or, where the law allows, by someone legally authorised to decide for you.
You can keep asking questions during the study, you are told of new information that matters, and you can choose to leave at any time.
Weight in kilograms divided by height in metres squared. Example: 70 kg and 1.75 m gives 70 ÷ (1.75 × 1.75) ≈ 22.9.
What counts as overweight or obesity differs between countries (some use lower cut-offs), so go by the range the study states.
Ways of preventing pregnancy. “Highly effective” methods fail less than 1% of the time a year when used correctly — for example an IUD or an implant.
Criteria usually say which methods count and how long to keep using them after the last dose, sometimes for male participants too. Some studies accept a partner’s vasectomy if it was confirmed successful and that person is the participant’s only sexual partner.
Periods have stopped for good: usually no period for 12 months in a row without another medical reason, sometimes confirmed by a blood test (FSH).
Judged by the study doctor to matter for your health or for the study. It is a doctor’s decision, so ask the study team if you are unsure whether something counts.
A condition in which the immune system attacks the body’s own tissues, such as rheumatoid arthritis, lupus, psoriasis, type 1 diabetes or inflammatory bowel disease.
Immunotherapy studies often leave out active autoimmune disease, and some name exceptions, such as thyroid disease on replacement hormone. Check the exceptions this study lists.
Hepatitis B is a virus that infects the liver. These are separate tests: HBsAg positive usually means a current infection (a recent vaccination can briefly cause it too); total anti-HBc (HBcAb) positive means an infection now or in the past; HBV DNA measures how much virus is in the blood.
Some studies accept a past infection if HBV DNA is undetectable, sometimes with antiviral medicine during the study. Check what this study allows.
Hepatitis C is a virus that infects the liver. An HCV antibody test can stay positive after an infection has cleared (and is occasionally positive without one); an HCV RNA test shows whether the virus is there now.
After treatment, hepatitis C counts as cured when HCV RNA is still undetectable 12 weeks or more after the treatment ended. Studies often accept people cured this way.
The human immunodeficiency virus, which weakens the immune system.
Many studies now accept people whose HIV is controlled on treatment, judged by the viral load and the CD4 count. Check the limits this study sets.
An allergy, or another reaction of the immune system, to a substance. “Hypersensitivity to the study drug” means a known allergic reaction to it — not every side effect a medicine can have.
A recording of the heart’s electrical activity, taken with stickers on the chest, arms and legs. It takes a few minutes and does not hurt.
Malignancy means cancer. Criteria about another or earlier malignancy ask whether you have had a different cancer, usually within a set number of years.
Some are commonly allowed, such as treated skin cancers other than melanoma and early cancers removed completely — check the exceptions this study lists.
A weakened immune system. It can come from an illness, such as HIV or some blood cancers, or from medicines that turn the immune system down, for example after an organ transplant or for an autoimmune disease; steroids at higher doses count.
Read whether the line is about a condition or about medicines, and which medicines and doses it means.
Anti-inflammatory medicines such as prednisone, prednisolone and dexamethasone — not the anabolic steroids used for muscle.
Studies differ in what they allow: check which steroid medicines, routes (tablets, injections, creams, inhalers, eye drops) and doses this study accepts.
Informed consent
Before you join, the study team explains what taking part involves — its purpose, what happens, the risks and possible benefits — and answers your questions, so you can decide freely. Consent is usually recorded on a form (the informed consent form, ICF) signed by you or, where the law allows, by someone legally authorised to decide for you.
You can keep asking questions during the study, you are told of new information that matters, and you can choose to leave at any time.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
BMI (body mass index)
Weight in kilograms divided by height in metres squared. Example: 70 kg and 1.75 m gives 70 ÷ (1.75 × 1.75) ≈ 22.9.
What counts as overweight or obesity differs between countries (some use lower cut-offs), so go by the range the study states.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Contraception
Ways of preventing pregnancy. “Highly effective” methods fail less than 1% of the time a year when used correctly — for example an IUD or an implant.
Criteria usually say which methods count and how long to keep using them after the last dose, sometimes for male participants too. Some studies accept a partner’s vasectomy if it was confirmed successful and that person is the participant’s only sexual partner.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Postmenopausal
Periods have stopped for good: usually no period for 12 months in a row without another medical reason, sometimes confirmed by a blood test (FSH).
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Clinically significant
Judged by the study doctor to matter for your health or for the study. It is a doctor’s decision, so ask the study team if you are unsure whether something counts.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Autoimmune disease
A condition in which the immune system attacks the body’s own tissues, such as rheumatoid arthritis, lupus, psoriasis, type 1 diabetes or inflammatory bowel disease.
Immunotherapy studies often leave out active autoimmune disease, and some name exceptions, such as thyroid disease on replacement hormone. Check the exceptions this study lists.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Hepatitis B tests
Hepatitis B is a virus that infects the liver. These are separate tests: HBsAg positive usually means a current infection (a recent vaccination can briefly cause it too); total anti-HBc (HBcAb) positive means an infection now or in the past; HBV DNA measures how much virus is in the blood.
Some studies accept a past infection if HBV DNA is undetectable, sometimes with antiviral medicine during the study. Check what this study allows.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Hepatitis C tests
Hepatitis C is a virus that infects the liver. An HCV antibody test can stay positive after an infection has cleared (and is occasionally positive without one); an HCV RNA test shows whether the virus is there now.
After treatment, hepatitis C counts as cured when HCV RNA is still undetectable 12 weeks or more after the treatment ended. Studies often accept people cured this way.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
HIV
The human immunodeficiency virus, which weakens the immune system.
Many studies now accept people whose HIV is controlled on treatment, judged by the viral load and the CD4 count. Check the limits this study sets.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Hypersensitivity
An allergy, or another reaction of the immune system, to a substance. “Hypersensitivity to the study drug” means a known allergic reaction to it — not every side effect a medicine can have.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
ECG (electrocardiogram)
A recording of the heart’s electrical activity, taken with stickers on the chest, arms and legs. It takes a few minutes and does not hurt.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Cancer (malignancy)
Malignancy means cancer. Criteria about another or earlier malignancy ask whether you have had a different cancer, usually within a set number of years.
Some are commonly allowed, such as treated skin cancers other than melanoma and early cancers removed completely — check the exceptions this study lists.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Immunosuppression
A weakened immune system. It can come from an illness, such as HIV or some blood cancers, or from medicines that turn the immune system down, for example after an organ transplant or for an autoimmune disease; steroids at higher doses count.
Read whether the line is about a condition or about medicines, and which medicines and doses it means.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Corticosteroids (steroids)
Anti-inflammatory medicines such as prednisone, prednisolone and dexamethasone — not the anabolic steroids used for muscle.
Studies differ in what they allow: check which steroid medicines, routes (tablets, injections, creams, inhalers, eye drops) and doses this study accepts.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Low dose level(3µg) for GBP560-A in stage 1. Participants will receive 2 doses of one of the test vaccines at 4-week intervals, respectively.
Biological: GBP560-A
Low dose level (3µg) for GBP560-B in stage 1. Participants will receive 2 doses of one of the test vaccines at 4-week intervals, respectively.
Biological: GBP560-B
Mid dose level (15µg) for GBP560-A in stage 1. Participants will receive 2 doses of one of the test vaccines at 4-week intervals, respectively.
Biological: GBP560-A
Mid dose level (15µg) for GBP560-B in stage 1. Participants will receive 2 doses of one of the test vaccines at 4-week intervals, respectively.
Biological: GBP560-B
High dose level (50µg) for GBP560-A in stage 1. Participants will receive 2 doses of one of the test vaccines at 4-week intervals, respectively.
Biological: GBP560-A
High dose level (50µg) for GBP560-B in stage 1. Participants will receive 2 doses of one of the test vaccines at 4-week intervals, respectively.
Biological: GBP560-B
Participants will receive 2 doses of one of the active comparators (IXIARO®, 6 Antigen Unit, corresponding to a potency of ≤ 460 ng ED) at 4-week intervals, respectively in Stage 1 and Stage 2.
Biological: IXIARO
Participants will receive 1 dose of placebo saline and 1 dose of another active comparator (IMOJEV®, 4.0 - 5.8 log PFU) at 4-week intervals, respectively in Stage 1 and Stage 2.
Biological: IMOJEV · Biological: Normal Saline (Placebo)
Participants will receive 2 intramuscular injections of the test vaccines in stage 2. 1st will be on Visit 2 and 2nd will be on Visit 5, in line with the selected dose regimen in stage 1.
Biological: GBP560-A · Biological: GBP560-B
Participants will receive 2 intramuscular injections of the test vaccines in stage 2. 1st will be on Visit 2 and 2nd will be on Visit 5, in line with the selected dose regimen in stage 1.
Biological: GBP560-A · Biological: GBP560-B
injection volume of 0.5mililiter (mL) with each dose on V2(1day) and V5 (29day) in stage1 and stage2. Low dose: 3μg Mid dose: 15μg High dose: 50μg
injection volume of 0.5mL with each dose on V2(1day) and V5 (29day) in stage1 and stage2. Low dose: 3μg Mid dose: 15μg High dose: 50μg
injection volume of 0.5mL on V2(1day) and V5 (29day) in stage1 and stage2
injection volume of 0.5mL on V5 (29day) in stage1 and stage2
injection volume of 0.5mL on V2 (1day) in stage1 and stage2 (This is for IMOJEV placebo)
Percentage of participants experiencing any immediate reactions
For all cohort
Time frame: 30 minutes (2 hours for the sentinel participants in stage 1) post each vaccination
Percentage of participants reporting any solicited local Adverse Event (AE)
For all cohort
Time frame: during the 7 days following each study vaccination
Percentage of participants reporting any solicited systemic Adverse Event (AE)
For all cohort
Time frame: during the 7 days following each study vaccination
Percentage of participants experiencing any unsolicited Adverse Event (AE)
For all cohort
Time frame: during the 28 days following each study vaccination
Percentage of participants with any Medically Attended Adverse Event (MAAE)
For all cohort
Time frame: until 6 months following the last study vaccination
Percentage of participants experiencing any Adverse Event of Special Interest (AESI)s, AEs leading to study withdrawal and Serious Adverse Event (SAE)s during the entire study period
For all cohort
Time frame: up to 12 months for stage 1 and up to 24 months for stage 2
Seroprotection rate for both the respective and cross Japanese encephalitis virus (JEV) strains of each vaccine (SA14-14-2 and Beijing-1 strain) in live-virus neutralizing antibody titers at each time point
For stage 2
Time frame: At baseline, 2 weeks, 4 weeks following the 1st study vaccination, and at 2 weeks, 4 weeks, 3 months, 6 months, 12 months, and 24 months following the 2nd study vaccination.
Seroresponse rate for both the respective and cross JEV strains of each vaccine (SA14-14-2 and Beijing-1 strain) in live-virus neutralizing antibody titers, from baseline to each subsequent time point
For Stage 2
Time frame: At baseline, 2 weeks, 4 weeks following the 1st study vaccination, and at 2 weeks, 4 weeks, 3 months, 6 months, 12 months, and 24 months following the 2nd study vaccination
Geometric Mean Titer (GMT) of neutralizing antibody against both the respective and cross JEV strains of each vaccine (SA14-14-2 and Beijing-1 strain) measured by a live-virus neutralization assay (PRNT) at each time point
For stage 2
Time frame: At baseline, 2 weeks, 4 weeks following the 1st study vaccination, and at 2 weeks, 4 weeks, 3 months, 6 months, 12 months, and 24 months following the 2nd study vaccination.
Geometric mean fold rise of neutralizing antibody against both the respective and cross JEV strains of each vaccine (SA14-14-2,Beijing-1 strain), measured by a live-virus neutralization assay(PRNT), from each pre-vaccination to each subsequent timepoint
For Stage 2
Time frame: At baseline, 2 weeks, 4 weeks following the 1st study vaccination, and at 2 weeks, 4 weeks, 3 months, 6 months, 12 months, and 24 months following the 2nd study vaccination
Geometric mean fold reduction of neutralizing antibody against both respective and cross JEV strains of each vaccine (SA-14-14-2,Beijing-1 strain), measured by live-virus neutralization assay (PRNT) from persistence baseline to each subsequent timepoint
For Stage 2
Time frame: At baseline, 2 weeks, 4 weeks following the 1st study vaccination, and at 2 weeks, 4 weeks, 3 months, 6 months, 12 months, and 24 months following the 2nd study vaccination.
Seroprotection rate for both the respective and cross JEV strains of each vaccine (SA14-14-2 and Beijing-1 strain) in live-virus neutralizing antibody titers at each time point
For Stage 1
Time frame: At baseline, 2 weeks, 4 weeks following the 1st study vaccination, and at 2 weeks, 4 weeks, 3 months, 6 months, and 12 months following the 2nd study vaccination
Seroresponse rate for both the respective and cross JEV strains of each vaccine (SA14-14-2 and Beijing-1 strain) in live-virus neutralizing antibody titers, from baseline to each subsequent time point.
For stage 1
Time frame: At baseline, 2 weeks, 4 weeks following the 1st study vaccination, and at 2 weeks, 4 weeks, 3 months, 6 months, and 12 months following the 2nd study vaccination
GMT of neutralizing antibody against both the respective and cross JEV strains of each vaccine (SA14-14-2 and Beijing-1 strain) measured by a live-virus neutralization assay (PRNT) at each time point
For stage 1
Time frame: At baseline, 2 weeks, 4 weeks following the 1st study vaccination, and at 2 weeks, 4 weeks, 3 months, 6 months, and 12 months following the 2nd study vaccination
Geometric mean fold rise of neutralizing antibody against both the respective and cross JEV strains of each vaccine (SA14-14-2,Beijing-1 strain), measured by live-virus neutralization assay(PRNT), from each pre-vaccination to each subsequent timepoint
For stage 1
Time frame: At baseline, 2 weeks, 4 weeks following the 1st study vaccination, and at 2 weeks, 4 weeks, 3 months, 6 months, and 12 months following the 2nd study vaccination.
Geometric mean fold reduction of neutralizing antibody against both respective and cross JEV strains of each vaccine (SA-14-14-2,Beijing-1 strain),measured by live-virus neutralization assay(PRNT) from persistence baseline to each subsequent timepoint
For Stage1
Time frame: At baseline, 2 weeks, 4 weeks following the 1st study vaccination, and at 2 weeks, 4 weeks, 3 months, 6 months, and 12 months following the 2nd study vaccination.
Cell-mediated response for cytokines expressed by Cluster of Differentiation 4+ Cluster of Differentiation 8+ T cells (Interferon-γ, Tumor Necrosis Factor-α, measured by Fluorescence-Activated Cell Sorting-Intracellular Cytokine Staining assay.
For all cohort
Time frame: At baseline, 4 weeks following the 1st study vaccination, and at 4 weeks and 6 months following the 2nd study vaccination
Seroprotection rate for the heterologous JEV strains of each vaccine (including, but not limited to K95A07, Bennett, JKT 6468, Sangju-v1 strains) in live-virus neutralizing antibody titers at each timepoint.
will be evaluated exclusively in a subset of approximately 20% of participants in stage 1, 10% of participants in stage 2
Time frame: At baseline, 2 weeks, 4 weeks following the 1st study vaccination, and at 2 weeks, 4 weeks, 3 months, 6 months, and 12 months following the 2nd study vaccination. and 24 months following the 2nd study vaccination (for stage2 only)
GMT of neutralizing antibody against the heterologous JEV strains of each vaccine (including, but not limited to K95A07, Bennett, JKT 6468, Sangju-v1 strains) measured by a live-virus neutralization assay (PRNT) at each timepoint
will be evaluated exclusively in a subset of approximately 20% of participants in stage 1, 10% of participants in stage 2
Time frame: At baseline, 2 weeks, 4 weeks following the 1st study vaccination, and at 2 weeks, 4 weeks, 3 months, 6 months, and 12 months following the 2nd study vaccination. and 24 months following the 2nd study vaccination (for stage2 only)
Seroresponse rate for the heterologous JEV strains of each vaccine (including, but not limited to K95A07, Bennett, JKT 6468, Sangju-v1 strains) in live-virus neutralizing antibody titers, from baseline to each subsequent time point
will be evaluated exclusively in a subset of approximately 20% of participants in stage 1, 10% of participants in stage 2
Time frame: At baseline, 2 weeks, 4 weeks following the 1st study vaccination, and at 2 weeks, 4 weeks, 3 months, 6 months, and 12 months following the 2nd study vaccination. and 24 months following the 2nd study vaccination (for stage2 only)
Geometric mean fold rise of neutralizing antibody against the heterologous JEV strains of each vaccine (including,but not limited to K95A07, Bennett, JKT 6468, Sangju-v1) measured by the PRNT assay, from each pre-vaccination to each subsequent time point
will be evaluated exclusively in a subset of approximately 20% of participants in stage 1, 10% of participants in stage 2.
Time frame: At baseline, 2 weeks, 4 weeks following the 1st study vaccination, and at 2 weeks, 4 weeks, 3 months, 6 months, and 12 months following the 2nd study vaccination. and 24 months following the 2nd study vaccination (for stage2 only)
Plan to share: No
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