SkyVaricella® (NBP608) Vaccine With Lower Potencies in Healthy Children Aged 12 Months to 12 Years

September 11, 2026 updated by: SK Bioscience Co., Ltd.

A Phase III, Randomized, Double-blinded, Active-controlled, Multinational, Multicenter Study to Assess the Safety and Immunogenicity of a Two-dose Regimen of SKYVaricella® (NBP608) in Children Aged 12 Months to 12 Years

The goal of this study is to evaluate the safety and immunogenicity of an investigational varicella vaccine in children. Researchers will compare the investigational vaccine, NBP608, with licensed varicella vaccines. The study includes children aged 12 months to 12 years.

Participants will be randomly assigned to receive either the investigational vaccine (NBP608) or licensed varicella vaccines.

Participants will:

Receive two subcutaneous injections of a study vaccine administered. Visit the study clinic seven times over approximately 15 months. Receive follow-up phone calls 7 days after each vaccination to monitor for safety.

Study Overview

Status

Recruiting

Conditions

Intervention / Treatment

Detailed Description

This is a Phase III, randomized, Double-blinded, Active-controlled, Multinational, Multicenter study designed to evaluate the safety and immunogenicity of a two-dose regimen of NBP608 in children aged 12 months to 12 years.

Immunogenicity will be assessed using blood samples collected at predefined time points to evaluate immune responses to varicella.

Safety will be evaluated throughout the study by monitoring adverse events (AEs), serious adverse events (SAEs), and adverse events of special interest (AESIs) following vaccination.

Each participant will take part in the study for approximately 15 months, including scheduled clinic visits and follow-up assessments.

Study Type

Interventional

Enrollment (Estimated)

780

Phase

  • Phase 3

Contacts and Locations

This section provides the contact details for those conducting the study, and information on where this study is being conducted.

Study Contact

Study Locations

  • Honduras
    • Cortés Department
      • San Pedro Sula, Cortés Department, Honduras, 21104
        • Not yet recruiting
        • San Pedro Sula, site 101
    • Francisco Morazán Department
      • Tegucigalpa, Francisco Morazán Department, Honduras, 11101
        • Recruiting
        • Tegucigalpa, site 102
  • Philippines
    • National Capital Region
      • Manila, National Capital Region, Philippines, 1000
        • Recruiting
        • Manila, site 301
      • Quezon City, National Capital Region, Philippines, 1113
        • Recruiting
        • Quezon City, site 302
      • Quezon City, National Capital Region, Philippines, 1118
        • Recruiting
        • Quezon City, site 303
  • South Korea
    • Daegu
      • Daegu, Daegu, South Korea, 42601
        • Recruiting
        • Daegu, site 404
    • Gyeonggi-do
      • Ansan, Gyeonggi-do, South Korea, 15355
        • Recruiting
        • Ansan, site 401
      • Hwaseong-si, Gyeonggi-do, South Korea, 18450
        • Not yet recruiting
        • Hwaseong-si, site 406
      • Seongnam-si, Gyeonggi-do, South Korea, 13620
        • Not yet recruiting
        • Seongnam-sit, site 405
    • Incheon
      • Incheon, Incheon, South Korea, 21431
        • Recruiting
        • Incheon, site 403
    • Seoul
      • Seoul, Seoul, South Korea, 02841
        • Recruiting
        • Seoul, site 402
      • Seoul, Seoul, South Korea, 07985
        • Not yet recruiting
        • Seoul, site 408
      • Seoul, Seoul, South Korea, 08308
        • Not yet recruiting
        • Seoul, site 407
  • Thailand
    • Changwat Khon Kaen
      • Khon Kaen, Changwat Khon Kaen, Thailand, 40002
        • Not yet recruiting
        • Khon Kaen City, site 201

Participation Criteria

Researchers look for people who fit a certain description, called eligibility criteria. Some examples of these criteria are a person's general health condition or prior treatments.

Eligibility Criteria

Ages Eligible for Study

  • Child

Accepts Healthy Volunteers

Yes

Description

Inclusion Criteria:

  1. Participant must be ≥12 months to ≤12 years of age, at the time of informed consent.
  2. Participant is healthy or medically stable, as determined by the investigator through medical history, physical examination, and overall clinical assessment.
  3. Participant's parents/LARs are able and willing to comply with all study procedures and attend all scheduled visits.
  4. Female participants of childbearing potential must agree to comply with applicable contraceptive requirements as defined in the protocol.
  5. Female participants of a childbearing potential must have a negative urine pregnancy test at screening; pregnancy testing is not required for those not of childbearing potential.
  6. Participant's parents/LARs are capable of providing signed informed consent, including agreement to comply with the requirements and restrictions specified in this protocol and in the informed consent form (ICF), before initiation of any study-specific procedures. Where applicable, the participant must also be able to provide written assent in accordance with local regulations and IRB/IEC requirements.

Exclusion Criteria:

1. Participants with any acute illness, including fever or clinically significant symptoms, at the time of study vaccination. 2. History of varicella-zoster virus (VZV) infection or recent exposure to VZV.

3. Presence of household contacts at high risk for severe VZV infection 4. History of immunodeficiency, autoimmune disease, or other conditions affecting the immune system.

5. History of bleeding disorders contraindicating vaccination. 6. History of severe allergic reactions to vaccines or vaccine components. 7. History of Guillain-Barré syndrome associated with prior vaccination. 8. Active untreated tuberculosis infection. 9. Any significant medical condition that, in the investigator's judgment, may interfere with study participation or interpretation of results.

10. Prior receipt of any varicella-containing vaccine. 11. Receipt or planned use of vaccines, medications, immunoglobulins, blood products, or immunosuppressive therapies that may interfere with study evaluation, as defined in the protocol.

12. Participation in another clinical study involving an investigational intervention within a protocol-defined timeframe.

13. Study staff, investigators, and their immediate family members.

Study Plan

This section provides details of the study plan, including how the study is designed and what the study is measuring.

How is the study designed?

Design Details

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

Arms and Interventions

Participant Group / Arm
Intervention / Treatment
Experimental: Test group 1: NBP608 (Mid Potency)
Participants receive either a one-dose regimen or a two-dose regimen consisting of two subcutaneous injections administered.
Biological: NBP608 (Mid Potency)
NBP608 (mid potency) is a live attenuated varicella virus vaccine (Oka/SK strain).
Other: Normal Saline (Placebo)
Placebo consisting of normal saline (0.9% sodium chloride solution).
Experimental: Test group 2: NBP608 (Low Potency)
Participants receive either a one-dose regimen or a two-dose regimen consisting of two subcutaneous injections administered.
Other: Normal Saline (Placebo)
Placebo consisting of normal saline (0.9% sodium chloride solution).
Biological: NBP608 (Low Potency)
NBP608 (low potency) is a live attenuated varicella virus vaccine (Oka/SK strain).
Experimental: Active control group 1: Varivax®
Participants receive either a one-dose regimen or a two-dose regimen consisting of two subcutaneous injections administered.
Other: Normal Saline (Placebo)
Placebo consisting of normal saline (0.9% sodium chloride solution).
Biological: Varivax®
Varivax® is a licensed live attenuated varicella virus vaccine (Oka/Merck strain).
Experimental: Active control group 2: SKYVaricella®
Participants receive either a one-dose regimen or a two-dose regimen consisting of two subcutaneous injections administered.
Other: Normal Saline (Placebo)
Placebo consisting of normal saline (0.9% sodium chloride solution).
Biological: SKYVaricella®
SKYVaricella® is a licensed live attenuated varicella virus vaccine (Oka/SK strain).

What is the study measuring?

Primary Outcome Measures

Outcome Measure
Measure Description
Time Frame
Seroconversion rate of varicella-zoster virus(VZV)
Time Frame: 6 weeks after each dose.
Seroconversion rate of varicella-zoster virus(VZV) IgG antibodies at 6 weeks after each vaccination
6 weeks after each dose.
Geometric mean antibody titer (GMT) of varicella-zoster virus(VZV) IgG antibodies
Time Frame: 6 weeks after the second dose.
Geometric mean antibody titer (GMT) of varicella-zoster virus(VZV) IgG antibodies at 6 weeks after the second vaccination
6 weeks after the second dose.

Secondary Outcome Measures

Outcome Measure
Measure Description
Time Frame
Seroconversion Rates
Time Frame: Time Frame: 6 weeks after each vaccination, 6 months after the second vaccination
Proportion of participants who are seronegative prior to vaccination at each specified assessment time point.
Time Frame: 6 weeks after each vaccination, 6 months after the second vaccination
Geometric Mean Titers (GMTs)
Time Frame: 6 weeks after each vaccination, 6 months after the second vaccination
VZV IgG antibodies at each specified time point.
6 weeks after each vaccination, 6 months after the second vaccination
Geometric Mean Fold Rise (GMFR)
Time Frame: from baseline to each post-vaccination timepoint
Fold increases in VZV IgG antibody titers
from baseline to each post-vaccination timepoint
Geometric Mean Fold Reduction (GMFRd)
Time Frame: from baseline to each post-vaccination timepoint
Fold reductions in VZV IgG antibody titers
from baseline to each post-vaccination timepoint
Immediate reactions
Time Frame: Within 30 minutes
Percentage of participants reporting any immediate reactions following each vaccination.
Within 30 minutes
Solicited adverse events
Time Frame: Within 14 days
Percentage of participants reporting solicited adverse events following each vaccination.
Within 14 days
Unsolicited adverse events
Time Frame: Within 42 days
Percentage of participants experiencing any unsolicited adverse events following each vaccination.
Within 42 days
Serious adverse events, medically attended AEs, and AEs leading to withdrawal
Time Frame: during study period
Percentage of participants experiencing any serious adverse events, medically attended adverse events, or adverse events leading to withdrawal during the study period.
during study period
Adverse events of special interest
Time Frame: during the study period
Percentage of participants experiencing any adverse events of special interest during the study period.
during the study period

Other Outcome Measures

Outcome Measure
Measure Description
Time Frame
Reverse cumulative distribution curves of VZV antibody titers
Time Frame: 6 weeks after each vaccination (Visit 2 and Visit 5)
Reverse cumulative distribution curves of VZV antibody titers measured by FAMA and gpELISA at 6 weeks after each study vaccination
6 weeks after each vaccination (Visit 2 and Visit 5)

Collaborators and Investigators

This is where you will find people and organizations involved with this study.

Sponsor

SK Bioscience Co., Ltd.

Study record dates

These dates track the progress of study record and summary results submissions to ClinicalTrials.gov. Study records and reported results are reviewed by the National Library of Medicine (NLM) to make sure they meet specific quality control standards before being posted on the public website.

Study Major Dates

Study Start (Actual)

July 4, 2026

Primary Completion (Estimated)

February 13, 2027

Study Completion (Estimated)

January 2, 2028

Study Registration Dates

First Submitted

January 27, 2026

First Submitted That Met QC Criteria

February 9, 2026

First Posted (Actual)

February 17, 2026

Study Record Updates

Last Update Posted (Actual)

September 15, 2026

Last Update Submitted That Met QC Criteria

September 11, 2026

Last Verified

September 1, 2026

More Information

Terms related to this study

Keywords

Additional Relevant MeSH Terms

Other Study ID Numbers

  • NBP608_004

Plan for Individual participant data (IPD)

Plan to Share Individual Participant Data (IPD)?

NO

Drug and device information, study documents

Studies a U.S. FDA-regulated drug product

No

Studies a U.S. FDA-regulated device product

No

This information was retrieved directly from the website clinicaltrials.gov without any changes. If you have any requests to change, remove or update your study details, please contact register@clinicaltrials.gov. As soon as a change is implemented on clinicaltrials.gov, this will be updated automatically on our website as well.

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