Immunogenicity and Safety of SYS6017 in the Participants Aged 40 Years and Above

A Randomized, Blinded, Placebo- and Active-Controlled, Adaptive Phase 2 Study to Evaluate the Immunogenicity and Safety of SYS6017 (a Herpes Zoster mRNA Vaccine) in Healthy Participants Aged 40 Years and Above

Herpes zoster is caused by the reactivation of latent varicella-zoster virus (VZV) which stays in latency after its primary infection. Immunosenescence contributes significantly to elevating morbidity associated with aging. Vaccination plays a key role in reducing the disease burden of zoster and the associated complications. We are conducting a study entitled "A Randomized, Blinded, Placebo- and Active-Controlled, Adaptive Phase 2 Clinical Trial to Evaluate the Immunogenicity and Safety of SYS6017 (a Herpes Zoster mRNA Vaccine) in Healthy Participants Aged 40 Years and Above".

Study Overview

• Status: Not yet recruiting
• Conditions: Herpes Zoster
• Intervention / Treatment: Biological: A zoster mRNA vaccine SYS6017; Other: Placebo; Biological: Active Comparator Vaccine

• Study Type: Interventional
• Enrollment (Estimated): 800
• Phase: Phase 2

Contacts and Locations

• Study Contact: Name: Clinical Trials Information Group officer; Phone Number: 86-0311-69085587; Email: ctr-contact@cspc.cn

Participation Criteria

Eligibility Criteria

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

Description

Inclusion Criteria:

• 1. Individuals aged 40 years or older;
• 2. Able to understand the study procedures, comply with the protocol requirements to attend all the scheduled visits, voluntarily consent to participate in the study, and sign the informed consent form;
• 3. Is physically eligible at the discretion of investigators based on medical history inquiry and physical examination; For participants with chronic underlying diseases (e.g., diabetes mellitus, hypertension, hyperlipidemia and other chronic conditions), they may be enrolled if their conditions have been well controlled within 3 months prior to enrollment in this study (i.e., additional medical interventions or major adjustments to treatments are not required);
• 4. For female participants of childbearing potential: No sexual activity or effective contraceptive methods were used within one menstrual cycle before enrollment; No pregnancy plans and agree to adopt effective contraceptive methods within 8 months after enrollment.

Exclusion Criteria:

• 1. History of zoster;
• 2. History of vaccination with varicella vaccine or zoster vaccine (including investigational vaccine);
• 3. Axillary temperature ≥ 37.1℃ on the day of enrollment or within 24 h before enrollment;
• 4. History of allergy to any component of the investigational vaccine; or history of severe allergic reactions to vaccines or medications (including but not limited to anaphylaxis, allergic laryngeal edema, Henoch-Schönlein purpura, thrombocytopenic purpura, or Arthus reaction);
• 5. History of myocarditis, pericarditis, or idiopathic cardiomyopathy, or any condition that could increases the risk of myocarditis or pericarditis
• 6. History of demyelinating diseases, including but not limited to Guillain-Barré syndrome, multiple sclerosis, ophthalmoneuromyelitis, acute disseminated encephalomyelitis, etc.;
• 7. Current epilepsy or convulsion, severe neurological or psychiatric disorders;
• 8. Have contraindications to intramuscular injection, e.g., diagnosed thrombocytopenia, any coagulation disorders, or ongoing treatment with anticoagulants, etc.;
• 9. Active malignant tumor, malignant tumor without adequate treatment, malignant tumor with a potential risk of recurrence during the study;
• 10. Active, unstable, severe or uncontrolled cardiovascular and cerebrovascular diseases, thrombotic diseases, blood and lymphatic system diseases, liver and kidney diseases, respiratory diseases, metabolic diseases, musculoskeletal diseases, autoimmune diseases, etc;
• 11. History of diagnosed immunocompromise or immunosuppression, congenital or functional asplenia, or splenectomy before enrollment;
• 12. Long-term (defined as more than 14 consecutive days) systemic use of immunosuppressants, immunostimulants, or other immunomodulatory drugs (e.g., corticosteroids at a dose of ≥ 20 mg/day prednisone or equivalent) within 6 months prior to enrollment; however, inhaled and topical corticosteroids are permitted; or planned administration of the aforementioned agents during the study period;
• 13. Administration of whole blood, plasma, serum, immunoglobulin, or monoclonal antibodies within 3 months prior to enrollment, or planned administration of the aforementioned products during the study period;
• 14. Blood donation or blood loss ≥ 450 mL within one month before enrollment, or planning to donate blood during the study;
• 15. Vaccination with any other vaccines within 30 days prior to enrollment, or planned vaccination with any other vaccines within 30 days after the last dose of the study vaccine;
• 16. Current participation in or planned participation in other clinical trials during the study period;
• 17. For female participants of childbearing potential: positive pregnancy test result prior to enrollment, current pregnancy or lactation, or planned pregnancy within 8 months after enrollment;
• 18. Unable to comply with the study procedures and requirements, or presence of other conditions that make the participant inappropriate for this clinical trial, as judged by the investigators.

Study Plan

How is the study designed?

Design Details

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

Number of Arms

7

Arms and Interventions

Participant Group / Arm	Intervention / Treatment
Placebo Comparator: Placebo	Other: Placebo; 0.9% saline，two-dose vaccination schedule (Month 0, 2)
Experimental: Dosage A of zoster mRNA vaccine SYS6017	Biological: A zoster mRNA vaccine SYS6017; SYS6017，two-dose vaccination schedule (Month 0, 2)
Experimental: Dosage B of zoster mRNA vaccine SYS6017	Biological: A zoster mRNA vaccine SYS6017; SYS6017，two-dose vaccination schedule (Month 0, 2)
Experimental: Dosage C of zoster mRNA vaccine SYS6017	Biological: A zoster mRNA vaccine SYS6017; SYS6017，two-dose vaccination schedule (Month 0, 2)
Experimental: Dosage D of zoster mRNA vaccine SYS6017	Biological: A zoster mRNA vaccine SYS6017; SYS6017，two-dose vaccination schedule (Month 0, 2)
Experimental: Dosage E of zoster mRNA vaccine SYS6017	Biological: A zoster mRNA vaccine SYS6017; SYS6017，two-dose vaccination schedule (Month 0, 2)
Active Comparator: Active Comparator Vaccine	Biological: Active Comparator Vaccine; Recombinant Zoster Vaccine (CHO cell)，two-dose vaccination schedule (Month 0, 2)

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Time Frame
solicited adverse events	within 14 days post each vaccination
unsolicited adverse events	within 30 days post each vaccination
Geometric Mean Concentration (GMC) of anti-gE antibody	On Day 14 and Day 30 after the completion of the full vaccination course
Geometric Mean Fold Increase (GMFI) of anti-gE antibody	On Day 14 and Day 30 after the completion of the full vaccination course
Seroconversion Rate (SCR) of anti-gE antibody	On Day 14 and Day 30 after the completion of the full vaccination course

Secondary Outcome Measures

Outcome Measure	Measure Description	Time Frame
serious adverse events		from the first vaccination through 12 months post the second vaccination
adverse events of special interest		from the first vaccination through 12 months post the second vaccination
pregnancy events reported by the participants		from the first vaccination through 12 months post the second vaccination
Geometric Mean Titer (GMT) of anti-VZV antibody		On Day 14 after the completion of the full vaccination course
Geometric Mean Fold Increase (GMFI) of anti-VZV antibody		On Day 14 after the completion of the full vaccination course
Seroconversion Rate (SCR) of anti-VZV antibody		On Day 14 after the completion of the full vaccination course
cellular immune response	the frequency of peripheral blood mononuclear cell (PBMC) secreting gE-specific cytokines	On Day 14 and Day 30 after the completion of the full vaccination course

Collaborators and Investigators

• Sponsor: CSPC Megalith Biopharmaceutical Co.,Ltd.

Study record dates

Study Major Dates

• Study Start (Estimated): January 10, 2026
• Primary Completion (Estimated): March 10, 2027
• Study Completion (Estimated): May 31, 2027

Study Registration Dates

• First Submitted: December 30, 2025
• First Submitted That Met QC Criteria: January 12, 2026
• First Posted (Actual): January 21, 2026

Study Record Updates

• Last Update Posted (Actual): January 21, 2026
• Last Update Submitted That Met QC Criteria: January 12, 2026
• Last Verified: January 1, 2026

More Information

Terms related to this study

• Additional Relevant MeSH Terms: Varicella Zoster Virus Infection; Infections; Virus Diseases; DNA Virus Infections; Herpesviridae Infections; Herpes Zoster
• Other Study ID Numbers: SYS6017-002

Drug and device information, study documents

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