Rabies Post-exposure ProphylaxisPhase 1NCT07342257
SYN023 With Rabies Vaccine in Healthy Pediatric Subjects
A Phase 1 study testing SYN023, Rabies Vaccine and HRIG in people with Rabies Post-exposure Prophylaxis, run by Synermore Biologics (Suzhou) Co., Ltd. at 1 site in China.
Trial summary
This study is a randomized, double-blind, active-controlled design. The goal is to evaluate the safety, pharmacokinetics and pharmacodynamic of SYN023 in combination with rabies vaccine in healthy participants under 18 years of age. Participants will: 1. Read more about this study
- Who is it for?
- Ages 0 to 17 yearsHealthy volunteers can take part
- Conditions the study is for
- Rabies Post-exposure Prophylaxis
- What is being tested?
- SYN023, Rabies Vaccine and HRIG
- Type of treatment
- Vaccines, Injection or infusion
- Could I receive a placebo?
- No, everyone receives an active treatment
- How many people
- 108 participants
- Where
- 1 siteChina
- Study dates
- 30 Nov 2024to 23 Jul 2025
- Phase
- Phase 1
- Are there results?
- None posted in the registry
Key requirements
Who can take part, as listed by the sponsor. Only the study team can confirm whether you are eligible, so take this list to your doctor.
- Ages 0 to 17 years
- All sexes
- Healthy volunteers accepted
- Child
Who may be able to join
- Under 18 years of age at enrollment, male or female, with legal identification available.
- Legal guardians of the volunteers voluntarily agree to participate in the study and sign the Informed Consent Form (ICF). Specifically, for volunteers under 8 years old, ICF is signed by legal guardians while fully respecting the child's opinion; for volunteers aged 8-17 years, legal guardians sign the ICF while volunteers themselves sign the ICF for minor volunteers;
- Willing and able to comply with all study procedures, expected to be able to complete all follow-up visits and maintain contact throughout the study period;
- Female volunteers of childbearing potential must have a negative urine pregnancy test prior to investigational product/vaccine administration, be non-lactating, and agree to use effective contraception during the study;
- In good general health with normal physical examination findings, vital signs measurements, and axillary temperature ≤ 37.0℃.
Who cannot join
- Subjects with history of injection of rabies vaccine and/or rabies virus passive immunization agents such as equine immunoglobulin, equine purified F (ab') 2 fragment products and HRIG;
- Subjects with history of being bitten by a dog, cat, ferret, fox, ferret, skunk, bat or raccoon (wound with skin damage) in the past 6 months;
- Subjects who have had pyrexia (≥ 37.3℃) or other acute illness within 7 days before enrollment, or are in acute exacerbation of chronic diseases;
- History or current presence of any autoimmune or immunodeficiency disorders (including but not limited to systemic lupus erythematosus, ankylosing spondylitis, autoimmune thyroid disease, HIV infection, etc.);
- Subjects with loss of splenic function or functional impairment, such as asplenia due to any condition (e.g., splenectomy);
- Subjects with a history of severe allergy to previous vaccination requiring medical intervention, such as generalized urticaria, allergic laryngeal edema, Henoch-Schonlein purpura, local allergic necrosis reaction (Arthus reaction), angioneurotic edema and anaphylactic shock; or known hypersensitivity to any component contained in the investigational products/vaccine;
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- History or current presence of any systemic disease or poorly controlled chronic condition that may interfere with safety or efficacy evaluations as determined by the investigator, including but not limited to hematologic disorders, hepatic/renal diseases, gastrointestinal disorders, respiratory diseases, malignancies, or history of major organ transplantation, etc.;
- History or current presence of severe neurological disorders (e.g., epilepsy, convulsions or seizures [excluding febrile seizures], encephalopathy) or psychiatric illness, or family history of psychiatric disorders;
- Presence of coagulation abnormalities (e.g., coagulation factor deficiency, platelet disorders);
- Administration of immunoglobulins or blood products within 3 months prior to enrollment, or planned use during the study;
- Receipt of systemic immunosuppressants or other immunomodulatory therapies within 3 months prior to enrollment, including but not limited to systemic corticosteroids (e.g., prednisone ≥ 2 mg/kg/day for > 2 weeks), or cytotoxic therapy, or planned administration during the trial;
- Participation in other clinical trials within 3 months prior to enrollment, or planned participation during the study;
- Administration of live-attenuated vaccines within 14 days or subunit/inactivated vaccines within 7 days prior to enrollment;
- Presence of skin lesions, inflammation, ulcers, rashes, or scars at the intended injection site that may interfere with administration or local reaction assessment;
- Any other condition considered by the investigator to render the participant unsuitable for study participation.
Trial locations and contacts
1 site in 1 country.
China1 site
Yuping Dong Autonomous County Center for Disease Control and Prevention
Tongren, Guizhou, 554000
About this study
Official title: A Randomized, Double-Blind, Active-Controlled, Phase I Clinical Trial to Evaluate the Safety, Pharmacokinetics, and Pharmacodynamics of Zamerovimab and Mazorelvimab Injection (SYN023) in Combination With Rabies Vaccine in Healthy Subjects Under 18 Years of Age
This study is a randomized, double-blind, active-controlled design. The goal is to evaluate the safety, pharmacokinetics and pharmacodynamic of SYN023 in combination with rabies vaccine in healthy participants under 18 years of age.
Participants will:
- Be randomly assigned to receive one of two doses of SYN023 or a dose of HRIG by intramuscular injection on Day 0, along with the first dose of the rabies vaccine.
- Receive additional doses of the rabies vaccine on Days 3, 7, 14, and 28.
- Have all adverse events (within 42 days) and all serious adverse events (within 126 days) after PEP administration collected and recorded.
- Provide several blood samples for pharmacokinetics and pharmacodynamic testing.
- Conditions
- Rabies Post-exposure Prophylaxis
- Being tested
- SYN023, Rabies Vaccine, HRIG
- Keywords
- rabies, pediatric, post-exposure prophylaxis, SYN023
- Medical subject headings
- Rabies
What participants receive
What participants receive. In a randomised study each person is assigned to one group by chance.
SYN023Biological
Also called Zamerovimab and Mazorelvimab Injection
SYN023 should be administered intramuscularly at sites distant from the vaccine injection site, either at the gluteus maximus or vastus lateralis muscles. The investigator should determine appropriate injection sites for multiple-point administration based on the participant's age and body weight. It is recommended that not more than 6 mL be administered per single gluteus maximus or vastus lateralis muscle, with not more than 4 mL per single injection site (younger children may require reduced volumes per muscle and per injection site based on individual circumstances); Injection time: Day 0.
Rabies VaccineBiological
Also called Freeze-dried Rabies Vaccine for Human Use (Vero Cells)
Dosage and administration of Rabies vaccine for human use: 0.5 mL, intramuscular injection in the deltoid muscle; Injection time: Days 0, 3, 7, 14, and 28 (Essen 5-dose regimen).
HRIGBiological
Also called Human Rabies Immunoglobulin
HRIG should be administered intramuscularly at sites distant from the vaccine injection site, either in the gluteus maximus or vastus lateralis muscles. The investigator should determine appropriate injection sites for multiple-point administration based on the participant's age and body weight. It is recommended that not more than 6 mL be administered per single gluteus maximus or vastus lateralis muscle, with not more than 4 mL per single injection site (younger children may require reduced volumes per muscle and per injection site based on individual circumstances); Injection time: Day 0.
| Study group | Role | What they receive |
|---|---|---|
| Low-dose SYN023 combined with rabies vaccine | Experimental | A single intramuscular injection of SYN023 at low dose combined with the Chinese licensed Vero Cell Rabies Vaccine (Essen 5-dose regimen) Receives: Biological: SYN023; Biological: Rabies Vaccine |
| High-dose SYN023 combined with rabies vaccine | Experimental | A single intramuscular injection of SYN023 at high dose combined with the Chinese licensed Vero Cell Rabies Vaccine (Essen 5-dose regimen) Receives: Biological: SYN023; Biological: Rabies Vaccine |
| HRIG combined with rabies vaccine | Active comparator | A single intramuscular injection of Human rabies immunoglobulin (HRIG）combined with the Chinese licensed Vero Cell Rabies Vaccine (Essen 5-dose regimen) Receives: Biological: Rabies Vaccine; Biological: HRIG |
What is being measured
The primary outcome is the main question the study is designed to answer.
Incidence of adverse drug reactions (ADRs) and adverse events (AEs)
Measured: 42 days
Incidence of serious adverse events (SAEs)
Measured: 126 days
Secondary outcomes (8)
Incidence of adverse reactions and adverse events
Measured: 30 minutes and 7 days
Rabies Virus Neutralizing Activity (RVNA) of Geometric Mean Concentration (GMC)
Rabies Virus Neutralizing Activity (RVNA) was assessed using Rapid Fluorescent Focus Inhibition Test (RFFIT).
Measured: Days 3, 7, 14, 42, 98 and 126
Percentage of Participants With Rabies Virus Neutralizing Activity (RVNA) ≥0.5 IU/mL
Rabies Virus Neutralizing Activity (RVNA) was assessed using Rapid Fluorescent Focus Inhibition Test (RFFIT).
Measured: Days 3, 7, 14, 42, 98 and 126
Area Under the Efficacy Curve for the Geometric Mean Concentration (GMC) of Rabies Virus Neutralizing Activity (RVNA)
Rabies Virus Neutralizing Activity (RVNA) was assessed using Rapid Fluorescent Focus Inhibition Test (RFFIT). Area Under the Efficacy Curve for the GMC of RVNA from Study Day 0 to Day 14 after administration (AUEC0-14)
Measured: Day 0 to Day 14
Maximum serum concentration (Cmax)
Cmax for SYN023 mAb components CTB011 and CTB012 will be estimated at Day 0 (pre-dose), Day 3, Day 7, Day 14, Day 42, Day 98 and Day 126 post-dose, using non compartmental analysis.
Measured: 126 days
Time to maximum concentration (Tmax)
Tmax for SYN023 mAb components CTB011 and CTB012 will be estimated at Day 0 (pre-dose), Day 3, Day 7, Day 14, Day 42, Day 98 and Day 126 post-dose, using non compartmental analysis.
Measured: 126 days
Area under the concentration-time curve (AUC0-t and AUC0-∞)
AUC0-t and AUC0-∞ for SYN023 mAb components CTB011 and CTB012 will be estimated at Day 0 (pre-dose), Day 3, Day 7, Day 14, Day 42, Day 98 and Day 126 post-dose, using non compartmental analysis.
Measured: 126 days
Terminal half-life (t1/2)
t1/2 for SYN023 mAb components CTB011 and CTB012 will be estimated at Day 0 (pre-dose), Day 3, Day 7, Day 14, Day 42, Day 98 and Day 126 post-dose, using non compartmental analysis.
Measured: 126 days
Timeline
From the start of the study to its completion; the mark is today. Estimated dates are the sponsor’s plan.
- First posted15 Jan 2026
- Study start30 Nov 2024
- Primary completion9 May 2025
- Study completion23 Jul 2025
Resources
- Official record on ClinicalTrials.govThe registry entry this page is built from, with its full change history.
- Other trials for Rabies Post-exposure ProphylaxisStudies of the same condition, open and under way.
- What the trial phases meanHow a treatment moves from first tests in people to approval.
More details
For doctors and researchers: how the study is designed, who runs it, and its registry IDs.
Study design
- Study type
- Interventional
- Phase
- Phase 1
- Primary purpose
- Treatment
- Allocation
- Randomised
- Intervention model
- Parallel groups
- Masking
- Quadruple blind
- Who is masked
- Participant, Care provider, Investigator, Outcomes assessor
- Enrolment
- 108 participants (actual)
Sponsor and investigators
- Lead sponsor
- Synermore Biologics (Suzhou) Co., Ltd.
- Sponsor type
- Industry (pharma, biotech, devices)
- Collaborators
- Guizhou Center for Disease Control and Prevention
- Responsible party
- Sponsor
IDs, dates and publications
- ClinicalTrials.gov ID
- NCT07342257
- Sponsor's protocol ID
- SYN023-007
- Status last verified
- Dec 2025
- First submitted
- 24 Dec 2025
- Last updated
- 15 Jan 2026
- Results posted
- No
- Data monitoring committee
- No
- FDA-regulated drug
- No
- FDA-regulated device
- No
Study at a glance
From the registry record, last updated by the sponsor on 15 Jan 2026. Recruitment status is as the sponsor reported it: confirm with the study team.
- Official title
- A Randomized, Double-Blind, Active-Controlled, Phase I Clinical Trial to Evaluate the Safety, Pharmacokinetics, and Pharmacodynamics of Zamerovimab and Mazorelvimab Injection (SYN023) in Combination With Rabies Vaccine in Healthy Subjects Under 18 Years of Age
- ClinicalTrials.gov ID
- NCT07342257
- Acronym / sponsor ID
- SYN023-007
- Conditions
- Rabies Post-exposure Prophylaxis
- Keywords
- rabies, pediatric, post-exposure prophylaxis, SYN023
- Phase
- Phase 1
- Study type
- Interventional
- Recruitment status
- Completed
- Enrolment
- 108 participants (actual)
- Lead sponsor
- Synermore Biologics (Suzhou) Co., Ltd.Industry (pharma, biotech, devices)
- Collaborators
- Guizhou Center for Disease Control and Prevention
- Study start
- 30 Nov 2024 (actual)
- Primary completion
- 9 May 2025 (actual)
- Study completion
- 23 Jul 2025 (actual)
- First posted
- 15 Jan 2026 (actual)
- Results
- Not posted in the source record
Clinical summary
The research question as the sponsor registered it. This describes what the study plans to test, not what it found.
This study is a randomized, double-blind, active-controlled design. The goal is to evaluate the safety, pharmacokinetics and pharmacodynamic of SYN023 in combination with rabies vaccine in healthy participants under 18 years of age.
Participants will:
- Be randomly assigned to receive one of two doses of SYN023 or a dose of HRIG by intramuscular injection on Day 0, along with the first dose of the rabies vaccine.
- Receive additional doses of the rabies vaccine on Days 3, 7, 14, and 28.
- Have all adverse events (within 42 days) and all serious adverse events (within 126 days) after PEP administration collected and recorded.
- Provide several blood samples for pharmacokinetics and pharmacodynamic testing.
Study design
- Primary purpose
- Treatment
- Allocation
- Randomised
- Intervention model
- Parallel groups
- Masking
- Quadruple blind (participant, care provider, investigator, outcomes assessor)
- Number of arms
- 3
| Arm | Type | Receives |
|---|---|---|
| Low-dose SYN023 combined with rabies vaccine | Experimental | Biological: SYN023, Biological: Rabies VaccineA single intramuscular injection of SYN023 at low dose combined with the Chinese licensed Vero Cell Rabies Vaccine (Essen 5-dose regimen) |
| High-dose SYN023 combined with rabies vaccine | Experimental | Biological: SYN023, Biological: Rabies VaccineA single intramuscular injection of SYN023 at high dose combined with the Chinese licensed Vero Cell Rabies Vaccine (Essen 5-dose regimen) |
| HRIG combined with rabies vaccine | Active comparator | Biological: Rabies Vaccine, Biological: HRIGA single intramuscular injection of Human rabies immunoglobulin (HRIG）combined with the Chinese licensed Vero Cell Rabies Vaccine (Essen 5-dose regimen) |
Who may qualify
- Ages
- 0 to 17 years
- Sex
- All
- Healthy volunteers
- Accepted
- Age groups
- Child
Key inclusion criteria (5 listed)
- Under 18 years of age at enrollment, male or female, with legal identification available.
- Legal guardians of the volunteers voluntarily agree to participate in the study and sign the Informed Consent Form (ICF). Specifically, for volunteers under 8 years old, ICF is signed by legal guardians while fully respecting the child's opinion; for volunteers aged 8-17 years, legal guardians sign the ICF while volunteers themselves sign the ICF for minor volunteers;
- Willing and able to comply with all study procedures, expected to be able to complete all follow-up visits and maintain contact throughout the study period;
- Female volunteers of childbearing potential must have a negative urine pregnancy test prior to investigational product/vaccine administration, be non-lactating, and agree to use effective contraception during the study;
- In good general health with normal physical examination findings, vital signs measurements, and axillary temperature ≤ 37.0℃.
Key exclusion criteria (15 listed)
- Subjects with history of injection of rabies vaccine and/or rabies virus passive immunization agents such as equine immunoglobulin, equine purified F (ab') 2 fragment products and HRIG;
- Subjects with history of being bitten by a dog, cat, ferret, fox, ferret, skunk, bat or raccoon (wound with skin damage) in the past 6 months;
- Subjects who have had pyrexia (≥ 37.3℃) or other acute illness within 7 days before enrollment, or are in acute exacerbation of chronic diseases;
- History or current presence of any autoimmune or immunodeficiency disorders (including but not limited to systemic lupus erythematosus, ankylosing spondylitis, autoimmune thyroid disease, HIV infection, etc.);
- Subjects with loss of splenic function or functional impairment, such as asplenia due to any condition (e.g., splenectomy);
Eligibility is decided by the study team after screening; this overview does not establish that a patient qualifies. Full inclusion and exclusion criteria.
Interventions
| Intervention | Type | Arms |
|---|---|---|
| SYN023Also: Zamerovimab and Mazorelvimab InjectionSYN023 should be administered intramuscularly at sites distant from the vaccine injection site, either at the gluteus maximus or vastus lateralis muscles. The investigator should determine appropriate injection sites for multiple-point administration based on the participant's age and body weight. It is recommended that not more than 6 mL be administered per single gluteus maximus or vastus lateralis muscle, with not more than 4 mL per single injection site (younger children may require reduced volumes per muscle and per injection site based on individual circumstances); Injection time: Day 0. | Biological | High-dose SYN023 combined with rabies vaccine, Low-dose SYN023 combined with rabies vaccine |
| Rabies VaccineAlso: Freeze-dried Rabies Vaccine for Human Use (Vero Cells)Dosage and administration of Rabies vaccine for human use: 0.5 mL, intramuscular injection in the deltoid muscle; Injection time: Days 0, 3, 7, 14, and 28 (Essen 5-dose regimen). | Biological | HRIG combined with rabies vaccine, High-dose SYN023 combined with rabies vaccine, Low-dose SYN023 combined with rabies vaccine |
| HRIGAlso: Human Rabies ImmunoglobulinHRIG should be administered intramuscularly at sites distant from the vaccine injection site, either in the gluteus maximus or vastus lateralis muscles. The investigator should determine appropriate injection sites for multiple-point administration based on the participant's age and body weight. It is recommended that not more than 6 mL be administered per single gluteus maximus or vastus lateralis muscle, with not more than 4 mL per single injection site (younger children may require reduced volumes per muscle and per injection site based on individual circumstances); Injection time: Day 0. | Biological | HRIG combined with rabies vaccine |
Primary outcome
Incidence of adverse drug reactions (ADRs) and adverse events (AEs)
Time frame: 42 days
Incidence of serious adverse events (SAEs)
Time frame: 126 days
8 secondary outcomes
Incidence of adverse reactions and adverse events
Time frame: 30 minutes and 7 days
Rabies Virus Neutralizing Activity (RVNA) of Geometric Mean Concentration (GMC)
Time frame: Days 3, 7, 14, 42, 98 and 126
Percentage of Participants With Rabies Virus Neutralizing Activity (RVNA) ≥0.5 IU/mL
Time frame: Days 3, 7, 14, 42, 98 and 126
Area Under the Efficacy Curve for the Geometric Mean Concentration (GMC) of Rabies Virus Neutralizing Activity (RVNA)
Time frame: Day 0 to Day 14
Maximum serum concentration (Cmax)
Time frame: 126 days
Time to maximum concentration (Tmax)
Time frame: 126 days
Area under the concentration-time curve (AUC0-t and AUC0-∞)
Time frame: 126 days
Terminal half-life (t1/2)
Time frame: 126 days
Results and safety
The study is completed, but results are not available in the source record. That does not mean the treatment did or did not work.
Research links
- Official record on ClinicalTrials.govLast updated by the sponsor 15 Jan 2026.
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Referral and contact
AzTrials does not enrol participants or take referrals. Contact the study team or a site listed below; they decide who can take part. This study is not recruiting at the moment.
The record lists no contact. Use the official record to reach the sponsor.
1 site in 1 country: see every site and its status.
Questions about this trial
What is this clinical trial studying?
A Phase 1 study testing SYN023, Rabies Vaccine and HRIG in people with Rabies Post-exposure Prophylaxis, run by Synermore Biologics (Suzhou) Co., Ltd. at 1 site in China.
The full registered description is in the About this study section and the official record.
Who may be eligible to take part?
The sponsor lists 5 inclusion and 15 exclusion criteria. Eligibility is decided by the study team after screening, so read the full criteria and contact a listed site.
Is this clinical trial currently recruiting?
The record says: finished, as of the sponsor's last update on 15 Jan 2026. Status can change between updates, so confirm with the study contact before making plans.
Where is the study taking place?
The record lists 1 site in China. Whether a site is taking part right now should be confirmed with that site. See every site.
What are the possible benefits and risks?
They depend on the study and the treatment, and no study can promise a benefit. The study team explains the known risks during informed consent, before anyone joins; the record itself does not list them.
What does this phase mean?
Phase 1 studies test a treatment in a small group of people for the first time or in a new way, mainly to check safety and find the right dose.
Not every study follows the same path, and some studies (observational studies, device studies) have no phase.
Are results available for this study?
The study is completed, but results are not available in the source record. That does not mean the treatment did or did not work.
How can a doctor refer a patient or contact the research team?
The record lists no contact. The official record names the sponsor, who can be asked directly. AzTrials does not enrol participants or take referrals.
What does the primary outcome measure?
Incidence of adverse drug reactions (ADRs) and adverse events (AEs) (time frame: 42 days). The study lists 2 primary outcomes in all. It is what the study was designed to measure, not a finding.
Where can I read the original study information?
Does a listing mean the treatment is approved or proven to work?
No. A listing means the study is registered. It does not show that the treatment is safe, works, or is approved by a regulator.
How often is this information updated?
AzTrials copies changed records from ClinicalTrials.gov every night and reloads the whole registry every week. The sponsor last updated this record on 15 Jan 2026.