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

NCT07415252 | Not Yet Recruiting Phase 3 DMC

• 1 other identifier: NBP608_004
• Study Type: interventional
• Target: 780
• Locations: 0 countries
• Sites: N/A

Brief Summary

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. Approximately 780 participants will take part in this study. Participants will be randomly assigned to receive either the investigational vaccine (NBP608) or licensed varicella vaccines. Some participants will receive two doses, while others will receive one dose, according to the assigned study group. Participants will: Receive two subcutaneous injections of a study vaccine, administered approximately three months apart (if applicable). Visit the study clinic seven times over approximately 15 months. Receive follow-up phone calls 7 days after each vaccination to monitor for safety.

Conditions

Varicella (Chickenpox)

Keywords

SKYVaricella; NBP608; Varicella vaccine; Chickenpox vaccine; Pediatric vaccination

Outcome Measures

Primary Outcomes (3)

• Difference in FAMA Assay-Measured Varicella-Zoster Virus (VZV) Seroconversion Rate 6 Weeks After the First Dose

  FAMA seroconversion rate will be assessed using the fluorescent antibody to membrane antigen (FAMA) assay to measure varicella-zoster virus (VZV) IgG antibodies and will be compared between the investigational vaccine (NBP608) and a licensed varicella vaccine (Varivax®) 6 weeks after the first dose. The FAMA seroconversion rate is defined as the proportion of participants who are seronegative at baseline (antibody titer \<1:4) and achieve a VZV IgG antibody titer ≥1:4 at the post-vaccination visit.

  6 weeks after the first dose.

• Difference in FAMA Assay-Measured Varicella-Zoster Virus (VZV) Seroconversion Rate 6 Weeks After the Second Dose

  FAMA seroconversion rate will be assessed using the fluorescent antibody to membrane antigen (FAMA) assay to measure varicella-zoster virus (VZV) IgG antibodies and will be compared between the investigational vaccine (NBP608) and a licensed varicella vaccine (Varivax®) 6 weeks after the second dose. The FAMA seroconversion rate is defined as the proportion of participants who are seronegative at baseline (antibody titer \<1:4) and achieve a VZV IgG antibody titer ≥1:4 at the post-vaccination visit.

  6 weeks after the second dose.

• Ratio of gpELISA Geometric Mean Titers 6 Weeks After the Second Dose

  gpELISA geometric mean titers will be compared between the investigational vaccine (NBP608) and a licensed varicella vaccine(Varivax®) 6 weeks after the second dose.

  6 weeks after the second dose.

Secondary Outcomes (11)

• FAMA Seroconversion Rates

  Baseline; 6 weeks and 3 months after the first vaccination; and 6 weeks, 6 months, and 12 months after the second vaccination

• gpELISA Seroconversion Rates

  Baseline; 6 weeks and 3 months after the first vaccination; and 6 weeks, 6 months, and 12 months after the second vaccination

• Geometric Mean Titers (GMTs)

  Baseline; 6 weeks and 3 months after the first vaccination; and 6 weeks, 6 months, and 12 months after the second vaccination

• Geometric Mean Fold Rise (GMFR)

  From pre-vaccination baseline to 12 months after the second dose (assessed at 6 weeks and 3 months after the first dose and at 6 weeks, 6 months, and 12 months after the second dose)

• Geometric Mean Fold Reduction (GMFRd)

  From persistence baseline (defined as the peak antibody titer observed post-dose 2) up to 12 months after the second dose (assessed at 6 months and 12 months after the second dose)

Other Outcomes (1)

• Reverse cumulative distribution curves of VZV antibody titers

  6 weeks after each vaccination (Visit 2 and Visit 5)

Study Arms (4)

Test group 1: NBP608 (Mid Potency)

EXPERIMENTAL

NBP608 (mid-potency) is a live attenuated varicella virus vaccine (Oka/SK strain). Participants receive either a one-dose regimen (active vaccine on Day 1 followed by placebo on Day 90) or a two-dose regimen consisting of two subcutaneous injections administered approximately 3 months apart.

Biological: NBP608 (Mid Potency); Other: Normal Saline (Placebo)

Test group 2: NBP608 (Low Potency)

EXPERIMENTAL

NBP608 (low-potency) is a live attenuated varicella virus vaccine (Oka/SK strain). Participants receive either a one-dose regimen (active vaccine on Day 1 followed by placebo on Day 90) or a two-dose regimen consisting of two subcutaneous injections administered approximately 3 months apart.

Biological: NBP608 (Low Potency); Other: Normal Saline (Placebo)

Active control group 1: Varivax®

EXPERIMENTAL

Varivax® is a licensed live attenuated varicella virus vaccine (Oka/Merck strain). Participants receive either a one-dose regimen (active vaccine on Day 1 followed by placebo on Day 90) or a two-dose regimen consisting of two subcutaneous injections administered approximately 3 months apart.

Biological: Varivax®; Other: Normal Saline (Placebo)

Active control group 2: SKYVaricella®

EXPERIMENTAL

SKYVaricella® is a licensed live attenuated varicella virus vaccine (Oka/SK strain). Participants receive either a one-dose regimen (active vaccine on Day 1 followed by placebo on Day 90) or a two-dose regimen consisting of two subcutaneous injections administered approximately 3 months apart.

Biological: SKYVaricella®; Other: Normal Saline (Placebo)

Interventions

NBP608 (Mid Potency) BIOLOGICAL

NBP608 (mid potency) is a live attenuated varicella virus vaccine (Oka/SK strain). It is supplied as a lyophilized single-dose vial with a separate diluent and administered as a 0.5 mL subcutaneous injection. Each dose contains ≥2,400 PFU after reconstitution.

Test group 1: NBP608 (Mid Potency)

NBP608 (Low Potency) BIOLOGICAL

NBP608 (low potency) is a live attenuated varicella virus vaccine (Oka/SK strain). It is supplied as a lyophilized single-dose vial with a separate diluent and administered as a 0.5 mL subcutaneous injection. Each dose contains ≥2,400 PFU after reconstitution.

Test group 2: NBP608 (Low Potency)

Varivax® BIOLOGICAL

Varivax® is a licensed live attenuated varicella virus vaccine (Oka/Merck strain). It is supplied as a lyophilized single-dose vial with a separate diluent and administered as a 0.5 mL subcutaneous injection. Each dose contains ≥1,350 PFU after reconstitution.

Active control group 1: Varivax®

SKYVaricella® BIOLOGICAL

SKYVaricella® is a licensed live attenuated varicella virus vaccine (Oka/SK strain). It is supplied as a lyophilized single-dose vial with a separate diluent and administered as a 0.5 mL subcutaneous injection. Each dose contains ≥2,400 PFU after reconstitution.

Active control group 2: SKYVaricella®

Normal Saline (Placebo) OTHER

Placebo consisting of normal saline (0.9% sodium chloride solution), administered as a 0.5 mL subcutaneous injection.

Active control group 1: Varivax®; Active control group 2: SKYVaricella®; Test group 1: NBP608 (Mid Potency); Test group 2: NBP608 (Low Potency)

Eligibility Criteria

• Age: 12 Months - 12 Years
• Sex: all
• Healthy Volunteers: Yes
• Age Groups: Child (0-17)

You may qualify if:

• Age
• Participant must be ≥12 months to ≤12 years of age, at the time of informed consent.
• Type of Participant and Disease Characteristics
• Participant is healthy or medically stable, as determined by the investigator through medical history, physical examination, and overall clinical assessment.
• \* Medically stable condition is defined as no significant change in therapy and no hospitalization for worsening disease within 8 weeks prior to the first study vaccination
• Participant's parents/LARs are able and willing to comply with all study procedures and attend all scheduled visits.
• Sex and Contraceptive/Barrier Requirements
• Female participants of childbearing potential (i.e., post-menarcheal females) must agree to maintain complete sexual abstinence from heterosexual intercourse, from at least 4 weeks prior to the first study vaccination and through 12 weeks following the second study vaccination (Visit 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.
• Informed Consent/Assent
• 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.

You may not qualify if:

• Medical Conditions
• Any clinically significant respiratory symptoms (e.g., cough, sore throat), febrile illness (tympanic temperature \>38°C), or acute illness within 24 hours prior to any study vaccination (Participant may be enrolled 24 hours after resolution of these symptoms).
• History of suspected or laboratory-confirmed VZV infection
• Close contact or household exposure to an individual with suspected or laboratory-confirmed VZV infection within 4 weeks prior to the first study vaccination.
• Household member(s) considered at high risk of severe VZV infection, including:
• Immunocompromised individuals
• Pregnant women or newborn infants whose mothers lack history of varicella infection or varicella vaccination
• Newborn infants born at \< 28 weeks gestational age.
• History of congenital, hereditary, acquired immunodeficiency, or autoimmune disease.
• History of bleeding disorder or thrombocytopenia contraindicating subcutaneous vaccination, based on the investigator's judgment.
• History of hypersensitivity and severe allergic reaction (e.g., anaphylaxis) to any vaccines or to any components of the study intervention, including gelatin or neomycin.
• History of Guillain-Barre syndrome following receipt of any prior vaccines.
• Active untreated tuberculosis infection.
• Significant unstable chronic or acute illness that, in the investigator's judgment, could pose a risk to the participant's safety, interfere with protocol-specified procedures, or complicate the interpretation of study results.
• Any other medical conditions that, in the opinion of the investigator, might interfere with the evaluation of study objectives (e.g., major congenital anomalies, neurological disorders, history of seizure disorders)

Sponsors & Collaborators

• SK Bioscience Co., Ltd.: lead

MeSH Terms

Conditions

Chickenpox

Interventions

Chickenpox Vaccine; Saline Solution

Condition Hierarchy (Ancestors)

Varicella Zoster Virus Infection; Herpesviridae Infections; DNA Virus Infections; Virus Diseases; Infections

Intervention Hierarchy (Ancestors)

Herpesvirus Vaccines; Viral Vaccines; Vaccines; Biological Products; Complex Mixtures; Crystalloid Solutions; Isotonic Solutions; Solutions; Pharmaceutical Preparations

Central Study Contacts

Bora Kim

CONTACT

82-2-2008-2200; bora.kim@sk.com

Study Design

• Study Type: interventional
• Phase: phase 3
• Allocation: RANDOMIZED
• Masking: QUADRUPLE
• Who Masked: PARTICIPANT, CARE PROVIDER, INVESTIGATOR, OUTCOMES ASSESSOR
• Purpose: PREVENTION
• Intervention Model: PARALLEL
• Sponsor Type: INDUSTRY
• Responsible Party: SPONSOR

Study Record Dates

• First Submitted: January 27, 2026
• First Posted: February 17, 2026
• Study Start: June 5, 2026
• Primary Completion (Estimated): February 13, 2027
• Study Completion (Estimated): January 2, 2028
• Last Updated: February 17, 2026

Record last verified: 2026-01

Data Sharing

• IPD Sharing: Will not share