ClinicalTrials.gg
CompletedNCT03961555ARPEPUpdated Jun 29, 2026Results posted

Comparison of SYN023 to Human Rabies Immune Globulin in Post Exposure Prophylaxis of Rabies

A Phase 2 interventional study of SYN023 and HRIG (HyperRab) in Rabies, sponsored by Synermore Biologics Co., Ltd.. Completed at 14 sites in 2 countries. Open to participants aged 18 Years and older. Per ClinicalTrials.gov, last updated 2026-06-29.

Sponsored by Synermore Biologics Co., Ltd. · Phase 2, Interventional, and Prevention

Phase
Phase 2
Study type
Interventional
Enrollment
448
Allocation
Randomized
Ages
18 Years and older
Sex
All
01

Study summary

This is a Phase 2b, double blinded, randomized study of SYN023 compared to HyperRab® (a licensed Rabies immune globulin from human sources, HRIG) for the prevention of rabies as part of post-exposure prophylaxis (PEP). The trial will enroll sequentially two different risk substrata of WHO Category 3 rabies exposure which are Low Risk Group (LRG) and Normal Risk Group (NRG). The enrollment will be stepwise while subject's data will be reviewed by data and safety monitoring board (DSMB) to confirm the safety and permit for next enrollment. Besides, rabies vaccine would be administered within 75 minutes after Study Drug in each group.

This trial is proposed to further the licensure of SYN023 to provide an effective PEP alternative available to those exposed persons who need such a product. A placebo-controlled rabies trial is unethical thus HRIG is selected as the control group. Rabies immune globulin from equine and human sources (HRIG) have been evaluated in many trials and HRIG is the standard of care in the United States.

02

Conditions studied

  • Rabies

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Keywords

  • Post-exposure prophylaxis of Rabies
03

In context

Rabies

114 studies on the registry are indexed under Rabies; 15 are open to participants now.

This study's enrollment of 448 is above the median of 201 across 104 interventional studies indexed under Rabies.

Browse Rabies studies →

Lead sponsor

Synermore Biologics Co., Ltd. is the lead sponsor of 5 studies on the registry; none are open to participants now.

Counted across the registry records on this site, refreshed daily.

04

Who can participate

Ages eligible
18 Years and older
Sexes eligible
All
Accepts healthy volunteers
No

Eligibility criteria

Inclusion Criteria (Low Risk Group):

Subjects must meet all of the following criteria at the time of subject ID assignment:

  1. History of dog, cat, mongoose, fox, ferret, skunk, bat or raccoon bite to trunk, leg, ankle or foot, or lick or scratch with, or of broken skin or mucous membrane saliva or neural tissue contamination, unprotected physical bat contact, scratch or saliva contamination of the head or neck without broken skin all ≤ 54 hours
  2. Has completed the written process and signed informed consent document
  3. Males and females
  4. Is age equal or more than 18 years on Study Day 1
  5. Agrees to stay in contact with the study site for the duration of the study, provide updated contact information as necessary, and has no current plans to move from the study area for the duration of the study
  6. Lives within 2 hour journey by available transportation to study center
  7. For female subjects: agrees to avoid pregnancy from Study Day 1 through Study Day 121. Women physically capable of pregnancy (not sterilized and still menstruating or within 1 year of the last menses if menopausal) in sexual relationships with men must use an acceptable method of avoiding pregnancy during this period. Acceptable methods of avoiding pregnancy include a sterile sexual partner, sexual abstinence (not engaging in sexual intercourse), hormonal (oral, injection, transdermal patch, or implant), vaginal ring, intrauterine device (IUD), or the combination of a condom or diaphragm with spermicide

Inclusion Criteria (Normal Risk Group)

Subjects must meet all of the following criteria at the time of subject ID assignment:

  1. History of dog, cat, mongoose, fox, ferret, skunk, bat or raccoon bite to any body part, lick or scratch with, or of broken skin, mucous membrane saliva or neural tissue contamination, or unprotected physical bat contact all ≤ 54 hours from post exposure prophylaxis (PEP)
  2. Has completed the written informed consent process and signed informed consent document.
  3. Males and females
  4. Is age equal or more than 18 years on Study Day 1
  5. Agrees to stay in contact with the study site for the duration of the study, provide updated contact information as necessary, and has no current plans to move from the study area for the duration of the study
  6. Lives within 2 hour journey by available transportation to study center
  7. For female subjects: agrees to avoid pregnancy from agrees to avoid pregnancy from Study Day 1 through Study Day 121. Women physically capable of pregnancy (not sterilized and still menstruating or within 1 year of the last menses if menopausal) in sexual relationships with men must use an acceptable method of avoiding pregnancy during this period. Acceptable methods of avoiding pregnancy include a sterile sexual partner, sexual abstinence (not engaging in sexual intercourse), hormonal contraceptives (oral, injection, transdermal patch, or implant), vaginal ring, intrauterine device (IUD), or the combination of a condom or diaphragm with spermicide

Exclusion Criteria:

Subjects must have had none of the following at the time of subject ID assignment:

  1. Clinical evidence of rabies infection
  2. Category 3 exposure > 54 hours before Study Drug receipt
  3. History or serological evidence of previous rabies vaccination
  4. Previous receipt of equine or human rabies globulin
  5. History of reaction to equine or human immunoglobulin.
  6. Received immunoglobulin or blood products within 42 days before Study Day 1
  7. Received any drug therapy or investigational vaccine within 60 days before Study Day 1
  8. Planned participation in any other investigational study during the study period.
  9. Receiving systemic medication such as systemic but not limited to systemic corticosteroids
  10. History or laboratory evidence of any past, present, or possible immunodeficiency state including but not limited to any laboratory indication of infection
  11. Previous medical history that may compromise the safety of the subject in the study according to the opinion of the principal investigator
  12. History or evidence on physical examination of any systemic disease or any acute or chronic illness that, in the opinion of the investigator, may interfere with the evaluation of the safety or activity of SYN023
  13. Pregnancy (results of the urine pregnancy test MUST be known before enrollment)
Terms in these criteria, in plain language(7)

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.

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.

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.

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.

Investigational drug or device

A drug or device being studied in a clinical trial.

It may be new, or already approved and being studied for another use, dose or form. Criteria often leave out people who took part in another study of one within a recent period, commonly 30 days or five half-lives.

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.

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.

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.

05

Study design

Phase
Phase 2
Primary purpose
Prevention
Allocation
Randomized
Intervention model
Parallel assignment
Masking
Quadruple (Participant, Care provider, Investigator, Outcomes assessor)
Enrollment
448 participants (actual)

Study arms

  • Experimental
    Low Risk Group: SYN023+Rabies vaccine

    The subjects were enrolled in the study sequentially into 2 different risk substrata of WHO Category 3 rabies exposure, which included Low Risk Group (LRG) and Normal Risk Group (NRG). Bites to the head, neck, genitalia arm or hand are not included in the LRG. The initial 20 subjects in the LRG were to be randomized on a 3:1 (SYN023 to Human Rabies Immune Globulin (HRIG)) ratio. The general 60 subjects in the LRG were to be allocated with a 1:1 randomization to either SYN023 or HRIG treatment arms. SYN023: * Interventions: are administered by direct injection into the wound or by subcutaneous or intramuscular injection when this is not possible * Dosage: 0.3 mg/kg of SYN023 * Frequency/duration: at Day 1 Rabies vaccine: * Interventions: should be administered in deltoid muscle * Dosage: 1 mL after reconstitution * Frequency/duration: Initial LRG subjects received 4 vaccine doses (Days 1, 4, 8,15); General LRG subjects received 5 vaccine doses (Days 1, 4, 8, 15, and 29).

    Biological: SYN023 · Biological: Rabies vaccine

  • Active comparator
    Low Risk Group: Human Rabies Immune Globulin (HRIG)+Rabies vaccine

    The subjects were enrolled in the study sequentially into 2 different risk substrata of WHO Category 3 rabies exposure, which included Low Risk Group (LRG) and Normal Risk Group (NRG). Bites to the head, neck, genitalia arm or hand are not included in the LRG. The initial 20 subjects in the LRG were to be randomized on a 3:1 (SYN023 to Human Rabies Immune Globulin (HRIG)) ratio. The general 60 subjects in the LRG were to be allocated with a 1:1 randomization to either SYN023 or HRIG treatment. HRIG: * Interventions: are administered by direct injection into the wound or by subcutaneous or intramuscular injection when this is not possible * Dosage: 20 IU/kg * Frequency/duration: at Day 1 Rabies vaccine : * Interventions: should be administered in deltoid muscle * Dosage: 1 mL after reconstitution * Frequency/duration: Initial LRG subjects received 4 vaccine doses (Days 1, 4, 8,15); General LRG subjects received 5 vaccine doses (Days 1, 4, 8, 15, and 29)

    Biological: HRIG (HyperRab) · Biological: Rabies vaccine

  • Experimental
    Normal Risk Group: SYN023+Rabies vaccine

    The subjects were enrolled in the study sequentially into 2 different risk substrata of WHO Category 3 rabies exposure, which included Low Risk Group (LRG) and Normal Risk Group (NRG). The NRG were consisted of all WHO Category 3 exposure. Subjects were to be allocated with a 1:1 randomization to either SYN023 or Human Rabies Immune Globulin (HRIG) treatment arms. SYN023: * Interventions: are administered by direct injection into the wound or by subcutaneous or intramuscular injection when this is not possible * Dosage: 0.3 mg/kg of SYN023 * Frequency/duration: at Day 1 Rabies vaccine: * Interventions: should be administered in deltoid muscle * Dosage: 1 mL after reconstitution * Frequency/duration: at Day 1, 4, 8, 15, 29

    Biological: SYN023 · Biological: Rabies vaccine

  • Active comparator
    Normal Risk Group: Human Rabies Immune Globulin (HRIG)+Rabies vaccine

    The subjects were enrolled in the study sequentially into 2 different risk substrata of WHO Category 3 rabies exposure, which included Low Risk Group (LRG) and Normal Risk Group (NRG). The NRG were consisted of all WHO Category 3 exposure. Subjects were to be allocated with a 1:1 randomization to either SYN023 or Human Rabies Immune Globulin (HRIG) treatment arms. HRIG: * Interventions: are administered by direct injection into the wound or by subcutaneous or intramuscular injection when this is not possible * Dosage: 20 IU/kg * Frequency/duration: at Day 1 Rabies vaccine (RabAvert/Rabipur): * Interventions: should be administered in deltoid muscle * Dosage: 1 mL after reconstitution * Frequency/duration: at Day 1, 4, 8, 15, 29

    Biological: HRIG (HyperRab) · Biological: Rabies vaccine

Interventions

  • BiologicalSYN023

    it is administered by direct injection into the wound or by subcutaneous or intramuscular injection when this is not possible

  • BiologicalHRIG (HyperRab)

    it is administered by direct injection into the wound or by subcutaneous or intramuscular injection when this is not possible

  • BiologicalRabies vaccine

    it should be administered in deltoid muscle

    Also known as: RabAvert, Rabipur

06

What researchers measure

Primary outcomes

  1. Rabies Virus Neutralizing Activity (RVNA) of Geometric Mean Concentration (GMC) at Study Day 8

    Rabies Virus Neutralizing Activity (RVNA) was assessed using Rapid Fluorescent Focus Inhibition Test (RFFIT).

    Time frame: Day 8

  2. Rabies Virus Neutralizing Activity (RVNA) of Geometric Mean Concentration (GMC) at Study Day 99

    Rabies Virus Neutralizing Activity (RVNA) was assessed using Rapid Fluorescent Focus Inhibition Test (RFFIT).

    Time frame: Day 99

  3. Percentage of Participants With Rabies Virus Neutralizing Activity (RVNA) ≥0.5 IU/mL at Study Day 99

    Rabies Virus Neutralizing Activity (RVNA) was assessed using Rapid Fluorescent Focus Inhibition Test (RFFIT).

    Time frame: Day 99

  4. Cases of Probable and Confirmed Rabies

    Case Classification Human Rabies * Suspected: A case that is compatible with the clinical case definition * Probable: A suspected case (above) plus history of contact with a suspected rabid animal. * Confirmed: A suspected case that is laboratory-confirmed.

    Time frame: Day 1 to Day 365

Secondary outcomes

  1. Rabies Virus Neutralizing Activity (RVNA) of Geometric Mean Concentration (GMC) at Study Day 4

    Rabies Virus Neutralizing Activity (RVNA) was assessed using Rapid Fluorescent Focus Inhibition Test (RFFIT).

    Time frame: Day 4

  2. 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 1 to Day 15 after administration (AUEC1-15)

    Time frame: Day 1 to Day 15

Other outcomes

  1. Maximum Observed Serum Concentration (Cmax)

    The Cmax of CTB011 and CTB012 derived from non-compartmental analysis.

    Time frame: Day 1 to Day 99

  2. Time of Maximum Observed Serum Concentration (Tmax)

    The Tmax of CTB011 and CTB012 derived from non-compartmental analysis.

    Time frame: Day 1 to Day 99

  3. Area Under the Serum Concentration-time Curve From Time 0 on Study Day 1 to Last Time Point (AUC1-t)

    The Area Under the Serum Concentration-time Curve From Time 0 on Study Day 1 to Last Time Point (AUC1-t) of CTB011 and CTB012 derived from non-compartmental analysis.

    Time frame: Day 1 to Day 99

  4. Area Under the Serum Concentration-time Curve From Time 0 on Study Day 1 to Infinity (AUC1-inf)

    The Area Under the Serum Concentration-time Curve From Time 0 on Study Day 1 to Infinity (AUC1-inf) of CTB011 and CTB012 derived from non-compartmental analysis.

    Time frame: Day 1 to Day 99

  5. Terminal Half-life (t1/2)

    The t1/2 of CTB011 and CTB012 derived from non-compartmental analysis.

    Time frame: Day 1 to Day 99

  6. Terminal Elimination Rate Constant (λz)

    The λz of CTB011 and CTB012 derived from non-compartmental analysis.

    Time frame: Day 1 to Day 99

  7. Apparent Clearance (CL/F)

    The CL/F of CTB011 and CTB012 derived from non-compartmental analysis.

    Time frame: Day 1 to Day 99

  8. Apparent Volume of Distribution (Vd/F)

    The Vd/F of CTB011 and CTB012 derived from non-compartmental analysis.

    Time frame: Day 1 to Day 99

  9. Anti-CTB011 and Anti-CTB012 Antibody

    Count of Subjects With Antibodies (CTB011 and CTB012) Status by Time Point

    Time frame: Day 1 to Day 99

  10. Number of Subjects With at Least 1 Adverse Event

    The number of subjects with at least 1 unsolicited or solicited adverse events. Solicited adverse events: subjects were specifically asked about local adverse events (injection site pain, tenderness, redness swelling, warmth, skin disruption, regional lymphadenopathy) and non-local adverse events (headache, arthralgia, myalgia, rash, pruritus, urticaria, dyspnea, chest pain, cough, fever, chills) up to Study Day 8. Unsolicited adverse events were collected from Study Day 1 to Study Day 43.

    Time frame: Solicited adverse events: Day 1 to day 8, Unsolicited adverse events:Day 1 to day 43

07

Results

Posted Jan 16, 2026

Participant flow

Participant flow — Overall Study
MilestoneLow Risk Group: SYN023+Rabies VaccineLow Risk Group: Human Rabies Immune Globulin (HRIG)+Rabies VaccineNormal Risk Group: SYN023+Rabies VaccineNormal Risk Group: Human Rabies Immune Globulin (HRIG)+Rabies Vaccine
Started4535184184
Completed4534178178
Not completed0166
Withdrew: Lost to follow-up0010
Withdrew: Withdrawal by subject0024
Withdrew: Death0100
Withdrew: Other0022
Withdrew: No treatment received0010

Outcome measures

PrimaryRabies Virus Neutralizing Activity (RVNA) of Geometric Mean Concentration (GMC) at Study Day 8

Rabies Virus Neutralizing Activity (RVNA) was assessed using Rapid Fluorescent Focus Inhibition Test (RFFIT).

Time frame:
Day 8
Reported as:
Geometric mean · IU/mL
Rabies Virus Neutralizing Activity (RVNA) of Geometric Mean Concentration (GMC) at Study Day 8
IU/mLLow Risk Group: SYN023+Rabies VaccineLow Risk Group: Human Rabies Immune Globulin (HRIG)+Rabies VaccineNormal Risk Group: SYN023+Rabies VaccineNormal Risk Group: Human Rabies Immune Globulin (HRIG)+Rabies Vaccine
Rabies Virus Neutralizing Activity (RVNA) of Geometric Mean Concentration (GMC) at Study Day 84.70 ± 0.370.13 ± 0.103.30 ± 0.610.17 ± 1.39
PrimaryRabies Virus Neutralizing Activity (RVNA) of Geometric Mean Concentration (GMC) at Study Day 99

Rabies Virus Neutralizing Activity (RVNA) was assessed using Rapid Fluorescent Focus Inhibition Test (RFFIT).

Time frame:
Day 99
Reported as:
Geometric mean · IU/mL
Rabies Virus Neutralizing Activity (RVNA) of Geometric Mean Concentration (GMC) at Study Day 99
IU/mLLow Risk Group: SYN023+Rabies VaccineLow Risk Group: Human Rabies Immune Globulin (HRIG)+Rabies VaccineNormal Risk Group: SYN023+Rabies VaccineNormal Risk Group: Human Rabies Immune Globulin (HRIG)+Rabies Vaccine
Rabies Virus Neutralizing Activity (RVNA) of Geometric Mean Concentration (GMC) at Study Day 990.66 ± 1.131.72 ± 1.830.97 ± 1.211.47 ± 1.60
PrimaryPercentage of Participants With Rabies Virus Neutralizing Activity (RVNA) ≥0.5 IU/mL at Study Day 99

Rabies Virus Neutralizing Activity (RVNA) was assessed using Rapid Fluorescent Focus Inhibition Test (RFFIT).

Time frame:
Day 99
Reported as:
Count of participants · Participants
Percentage of Participants With Rabies Virus Neutralizing Activity (RVNA) ≥0.5 IU/mL at Study Day 99
ParticipantsLow Risk Group: SYN023+Rabies VaccineLow Risk Group: Human Rabies Immune Globulin (HRIG)+Rabies VaccineNormal Risk Group: SYN023+Rabies VaccineNormal Risk Group: Human Rabies Immune Globulin (HRIG)+Rabies Vaccine
Percentage of Participants With Rabies Virus Neutralizing Activity (RVNA) ≥0.5 IU/mL at Study Day 993028138142
PrimaryCases of Probable and Confirmed Rabies

Case Classification Human Rabies * Suspected: A case that is compatible with the clinical case definition * Probable: A suspected case (above) plus history of contact with a suspected rabid animal. * Confirmed: A suspected case that is laboratory-confirmed.

Time frame:
Day 1 to Day 365
Reported as:
Number · participants
Cases of Probable and Confirmed Rabies
participantsLow Risk Group: SYN023+Rabies VaccineLow Risk Group: Human Rabies Immune Globulin (HRIG)+Rabies VaccineNormal Risk Group: SYN023+Rabies VaccineNormal Risk Group: Human Rabies Immune Globulin (HRIG)+Rabies Vaccine
Cases of Probable and Confirmed Rabies0000
SecondaryRabies Virus Neutralizing Activity (RVNA) of Geometric Mean Concentration (GMC) at Study Day 4

Rabies Virus Neutralizing Activity (RVNA) was assessed using Rapid Fluorescent Focus Inhibition Test (RFFIT).

Time frame:
Day 4
Reported as:
Geometric mean · IU/mL
Rabies Virus Neutralizing Activity (RVNA) of Geometric Mean Concentration (GMC) at Study Day 4
IU/mLLow Risk Group: SYN023+Rabies VaccineLow Risk Group: Human Rabies Immune Globulin (HRIG)+Rabies VaccineNormal Risk Group: SYN023+Rabies VaccineNormal Risk Group: Human Rabies Immune Globulin (HRIG)+Rabies Vaccine
Rabies Virus Neutralizing Activity (RVNA) of Geometric Mean Concentration (GMC) at Study Day 43.30 ± 1.270.12 ± 0.363.30 ± 0.600.14 ± 0.82
SecondaryArea 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 1 to Day 15 after administration (AUEC1-15)

Time frame:
Day 1 to Day 15
Reported as:
Geometric mean · day*IU/mL
Area Under the Efficacy Curve for the Geometric Mean Concentration (GMC) of Rabies Virus Neutralizing Activity (RVNA)
day*IU/mLLow Risk Group: SYN023+Rabies VaccineLow Risk Group: Human Rabies Immune Globulin (HRIG)+Rabies VaccineNormal Risk Group: SYN023+Rabies VaccineNormal Risk Group: Human Rabies Immune Globulin (HRIG)+Rabies Vaccine
Area Under the Efficacy Curve for the Geometric Mean Concentration (GMC) of Rabies Virus Neutralizing Activity (RVNA)42.91 ± 0.445.79 ± 1.4346.00 ± 0.579.81 ± 2.29
Other pre-specifiedMaximum Observed Serum Concentration (Cmax)

The Cmax of CTB011 and CTB012 derived from non-compartmental analysis.

Time frame:
Day 1 to Day 99
Reported as:
Geometric mean · ng/mL
Maximum Observed Serum Concentration (Cmax)
ng/mLLow Risk Group: SYN023+Rabies VaccineNormal Risk Group: SYN023+Rabies Vaccine
Cmax for CTB011903 ± 23.8700 ± 25.9
Cmax for CTB012916.5 ± 31.3628 ± 32.6
Other pre-specifiedTime of Maximum Observed Serum Concentration (Tmax)

The Tmax of CTB011 and CTB012 derived from non-compartmental analysis.

Time frame:
Day 1 to Day 99
Reported as:
Median · day
Time of Maximum Observed Serum Concentration (Tmax)
dayLow Risk Group: SYN023+Rabies VaccineNormal Risk Group: SYN023+Rabies Vaccine
Tmax for CTB0112.93 ± 0.232.89 ± 0.34
Tmax for CTB0122.87 ± 0.342.89 ± 0.34
Other pre-specifiedArea Under the Serum Concentration-time Curve From Time 0 on Study Day 1 to Last Time Point (AUC1-t)

The Area Under the Serum Concentration-time Curve From Time 0 on Study Day 1 to Last Time Point (AUC1-t) of CTB011 and CTB012 derived from non-compartmental analysis.

Time frame:
Day 1 to Day 99
Reported as:
Geometric mean · day*ng/mL
Area Under the Serum Concentration-time Curve From Time 0 on Study Day 1 to Last Time Point (AUC1-t)
day*ng/mLLow Risk Group: SYN023+Rabies VaccineNormal Risk Group: SYN023+Rabies Vaccine
AUC1-t for CTB01119500 ± 22.77640 ± 33.6
AUC1-t for CTB01217250 ± 34.26660 ± 33.7
Other pre-specifiedArea Under the Serum Concentration-time Curve From Time 0 on Study Day 1 to Infinity (AUC1-inf)

The Area Under the Serum Concentration-time Curve From Time 0 on Study Day 1 to Infinity (AUC1-inf) of CTB011 and CTB012 derived from non-compartmental analysis.

Time frame:
Day 1 to Day 99
Reported as:
Geometric mean · day*ng/mL
Area Under the Serum Concentration-time Curve From Time 0 on Study Day 1 to Infinity (AUC1-inf)
day*ng/mLLow Risk Group: SYN023+Rabies VaccineNormal Risk Group: SYN023+Rabies Vaccine
AUC1-inf for CTB01122200 ± 24.1—
AUC1-inf for CTB01223700 ± 16.9—
Other pre-specifiedTerminal Half-life (t1/2)

The t1/2 of CTB011 and CTB012 derived from non-compartmental analysis.

Time frame:
Day 1 to Day 99
Reported as:
Geometric mean · day
Terminal Half-life (t1/2)
dayLow Risk Group: SYN023+Rabies VaccineNormal Risk Group: SYN023+Rabies Vaccine
t1/2 for CTB01116.3 ± 27.716.6
t1/2 for CTB01216.9 ± 32.721.3
Other pre-specifiedTerminal Elimination Rate Constant (λz)

The λz of CTB011 and CTB012 derived from non-compartmental analysis.

Time frame:
Day 1 to Day 99
Reported as:
Geometric mean · 1/day
Terminal Elimination Rate Constant (λz)
1/dayLow Risk Group: SYN023+Rabies VaccineNormal Risk Group: SYN023+Rabies Vaccine
λz for CTB0110.0428 ± 27.70.0417
λz for CTB0120.0416 ± 32.70.0325
Other pre-specifiedApparent Clearance (CL/F)

The CL/F of CTB011 and CTB012 derived from non-compartmental analysis.

Time frame:
Day 1 to Day 99
Reported as:
Geometric mean · mL/day
Apparent Clearance (CL/F)
mL/dayLow Risk Group: SYN023+Rabies VaccineNormal Risk Group: SYN023+Rabies Vaccine
CL/F for CTB011878.5 ± 24.2—
CL/F for CTB012823.5 ± 24.3—
Other pre-specifiedApparent Volume of Distribution (Vd/F)

The Vd/F of CTB011 and CTB012 derived from non-compartmental analysis.

Time frame:
Day 1 to Day 99
Reported as:
Geometric mean · mL
Apparent Volume of Distribution (Vd/F)
mLLow Risk Group: SYN023+Rabies VaccineNormal Risk Group: SYN023+Rabies Vaccine
Vd/F for CTB01117450 ± 29.2—
Vd/F for CTB01216450 ± 17.4—
Other pre-specifiedAnti-CTB011 and Anti-CTB012 Antibody

Count of Subjects With Antibodies (CTB011 and CTB012) Status by Time Point

Time frame:
Day 1 to Day 99
Reported as:
Count of participants · Participants
Anti-CTB011 and Anti-CTB012 Antibody
ParticipantsNormal Risk Group: SYN023+Rabies VaccineNormal Risk Group: Human Rabies Immune Globulin (HRIG)+Rabies Vaccine
Day 1 (baseline) — Either is positive4146
Day 1 (baseline) — Both are negative113109
Day 15 — Either is positive4339
Day 15 — Both are negative111117
Day 99 — Either is positive4836
Day 99 — Both are negative105117
Other pre-specifiedNumber of Subjects With at Least 1 Adverse Event

The number of subjects with at least 1 unsolicited or solicited adverse events. Solicited adverse events: subjects were specifically asked about local adverse events (injection site pain, tenderness, redness swelling, warmth, skin disruption, regional lymphadenopathy) and non-local adverse events (headache, arthralgia, myalgia, rash, pruritus, urticaria, dyspnea, chest pain, cough, fever, chills) up to Study Day 8. Unsolicited adverse events were collected from Study Day 1 to Study Day 43.

Time frame:
Solicited adverse events: Day 1 to day 8, Unsolicited adverse events:Day 1 to day 43
Reported as:
Count of participants · Participants
Number of Subjects With at Least 1 Adverse Event
ParticipantsLow Risk Group: SYN023+Rabies VaccineLow Risk Group: Human Rabies Immune Globulin (HRIG)+Rabies VaccineNormal Risk Group: SYN023+Rabies VaccineNormal Risk Group: Human Rabies Immune Globulin (HRIG)+Rabies Vaccine
Unsolicited Treatment-Emergent Adverse Events9113528
Solicited Treatment-Emergent Adverse Events3177

Adverse events

Collected over 365 days. Non-serious events are listed at a 0% frequency threshold.

Adverse event summary by group
GroupDeathsSeriousOther
LRG: SYN023+Rabies Vaccine0/45 (0%)0/45 (0%)9/45 (20%)
LRG: HRIG+Rabies Vaccine1/35 (2.9%)1/35 (2.9%)11/35 (31.4%)
NRG: SYN023+Rabies Vaccine0/183 (0%)1/183 (0.5%)40/183 (21.9%)
NRG: HRIG+Rabies Vaccine0/184 (0%)2/184 (1.1%)30/184 (16.3%)
Most frequent serious events
Most frequent serious events
EventLRG: SYN023+Rabies VaccineLRG: HRIG+Rabies VaccineNRG: SYN023+Rabies VaccineNRG: HRIG+Rabies Vaccine
Breast cancer recurrentNeoplasms benign, malignant and unspecified (incl cysts and polyps)0/451/350/1830/184
Ruptured ectopic pregnancyPregnancy, puerperium and perinatal conditions0/450/351/1830/184
LeptospirosisInfections and infestations0/450/350/1831/184
Cerebrovascular accidentNervous system disorders0/450/350/1831/184
Most frequent other events
Showing 10 of 74
Most frequent other events
EventLRG: SYN023+Rabies VaccineLRG: HRIG+Rabies VaccineNRG: SYN023+Rabies VaccineNRG: HRIG+Rabies Vaccine
Upper respiratory tract infectionInfections and infestations1/454/352/1834/184
Urinary tract infectionInfections and infestations2/450/355/1832/184
ChillsGeneral disorders2/450/350/1830/184
Eosinophil count increasedInvestigations0/450/356/1830/184
NasopharyngitisInfections and infestations0/451/353/1830/184
Pyelonephritis acuteInfections and infestations0/451/350/1830/184
Muscle strainInjury, poisoning and procedural complications0/451/350/1831/184
Glucose tolerance impairedMetabolism and nutrition disorders0/451/350/1830/184
HypokalaemiaMetabolism and nutrition disorders0/451/350/1830/184
HeadacheNervous system disorders0/451/355/1835/184

Baseline characteristics

Baseline characteristics were summarized by treatment group for all subjects in the As-treated Population. The as-treated population grouped by actual treatment received included all randomly assigned subjects with at least one dose of study treatment.

Age, Continuous
Age, Continuous(years)Low Risk Group: SYN023+Rabies VaccineLow Risk Group: Human Rabies Immune Globulin (HRIG)+Rabies VaccineNormal Risk Group: SYN023+Rabies VaccineNormal Risk Group: Human Rabies Immune Globulin (HRIG)+Rabies VaccineTotal
Mean38.0 ± 14.2638.4 ± 13.7331.9 ± 11.3331.3 ± 12.4934.9 ± 12.95
Sex: Female, Male
Sex: Female, Male(Participants)Low Risk Group: SYN023+Rabies VaccineLow Risk Group: Human Rabies Immune Globulin (HRIG)+Rabies VaccineNormal Risk Group: SYN023+Rabies VaccineNormal Risk Group: Human Rabies Immune Globulin (HRIG)+Rabies VaccineTotal
Female24188584211
Male211798100236
Race/Ethnicity, Customized
Race/Ethnicity, Customized(Participants)Low Risk Group: SYN023+Rabies VaccineLow Risk Group: Human Rabies Immune Globulin (HRIG)+Rabies VaccineNormal Risk Group: SYN023+Rabies VaccineNormal Risk Group: Human Rabies Immune Globulin (HRIG)+Rabies VaccineTotal
Asian4535183184447
Race/Ethnicity, Customized
Race/Ethnicity, Customized(Participants)Low Risk Group: SYN023+Rabies VaccineLow Risk Group: Human Rabies Immune Globulin (HRIG)+Rabies VaccineNormal Risk Group: SYN023+Rabies VaccineNormal Risk Group: Human Rabies Immune Globulin (HRIG)+Rabies VaccineTotal
Hispanic or Latino00022
Not Hispanic or Latino4535183182445
Region of Enrollment
Region of Enrollment(participants)Low Risk Group: SYN023+Rabies VaccineLow Risk Group: Human Rabies Immune Globulin (HRIG)+Rabies VaccineNormal Risk Group: SYN023+Rabies VaccineNormal Risk Group: Human Rabies Immune Globulin (HRIG)+Rabies VaccineTotal
Philippines4535183184447
BMI
BMI(kg/m^2)Low Risk Group: SYN023+Rabies VaccineLow Risk Group: Human Rabies Immune Globulin (HRIG)+Rabies VaccineNormal Risk Group: SYN023+Rabies VaccineNormal Risk Group: Human Rabies Immune Globulin (HRIG)+Rabies VaccineTotal
Mean24.70 ± 4.61223.66 ± 4.73223.89 ± 4.78723.69 ± 4.57324.25 ± 4.664
08

Study locations

14 sites
  • University of Florida
    Gainesville, Florida 32610, United States
  • University of Iowa
    Iowa City, Iowa 52242, United States
  • Clinical Research Solutions PC -Milan
    Milan, Tennessee 38358, United States
  • University of Virginia
    Charlottesville, Virginia 22903, United States
  • Medical College of Wisconsin
    Milwaukee, Wisconsin 53226, United States
  • Baguio General Hospital and Medical Center
    Baguio City, Benguet 2600, Philippines
  • De La Salle Health Sciences Institute Independent Ethics Committee
    Cavite City, Calabarzon 4114, Philippines
  • Southern Philippines Medical Center
    Davao City, Davao (Region XI) 8000, Philippines
  • Manila Doctors Hospital Institutional Review Board
    Manila, National Capital Region 1000, Philippines
  • Asian Hospital and Medical Center
    Muntinlupa, National Capital Region 1780, Philippines
  • Center of Excellence in Drug Research, Evaluation and Studies, Inc.
    Muntinlupa, National Capital Region 1781, Philippines
  • Research Institute For Tropical Medicine
    Muntinlupa, National Capital Region 1781, Philippines
  • Far Eastern University Hospital Nicanor Reyes Medical Foundation
    Quezon City, National Capital Region 1118, Philippines
  • Mary Johnston Hospital
    Manila, Philippines
09

References and documents

Publications

  • Quiambao BP, Payumo RA, Roa C, Borja-Tabora CF, Emmeline Montellano M, Reyes MRL, Zoleta-De Jesus L, Capeding MR, Solimen DP, Barez MY, Reid C, Chuang A, Tsao E, McClain JB. A phase 2b, Randomized, double blinded comparison of the safety and efficacy of the monoclonal antibody mixture SYN023 and human rabies immune globulin in patients exposed to rabies. Vaccine. 2024 Sep 17;42(22):126018. doi: 10.1016/j.vaccine.2024.05.066. Epub 2024 Jun 4. PubMed 38834432 ↗

Study documents

PDFs hosted by the registry, ClinicalTrials.gov.

Individual participant data

Plan to share: No

10

Timeline

Tracking since Sep 25, 2026
ElapsedEstimatedEstimated, not yet reached

Ran from Sep 2019 to primary completion in Dec 2021, 27 months.

Results were first posted in Jan 2026, 4 years after primary completion.

How these figures are worked out, and which studies are left out of them.

Registered
May 16, 2019
First posted
May 23, 2019
StartActual
Sep 3, 2019
Primary completionActual
Dec 23, 2021
CompletionActual
Dec 23, 2021
Results first posted
Jan 16, 2026
Last update
Jun 29, 2026
What these dates mean
Start.
When the first participant enrolled; while estimated, when the study expects to open to recruitment.
Primary completion.
When the last participant was examined or treated to collect data for the study's main question, its primary outcome. A study that stopped early gives the date its data collection stopped.
Completion.
When the last participant's last visit took place, for every outcome, secondary ones and side effects included: the end of the study. Often later than primary completion, sometimes the same day.
Actual and Est.
Actual means the registry says the date has happened. Est. (estimated) is a date the sponsor plans or expects. It can still move, and the sponsor is expected to change it to actual once it has passed.
No changes since tracking began. The registry record was last updated on Jun 29, 2026, before this site started recording changes on Sep 25, 2026. Its history is on ClinicalTrials.gov ↗
11

Registry details

Key details

Study ID
NCT03961555
Lead sponsor
Synermore Biologics Co., Ltd.
Collaborators
Synermore Biologics USA Limited
Responsible party
Sponsor
First posted
May 23, 2019
Start date
Sep 3, 2019
Primary completion
Dec 23, 2021
Completion
Dec 23, 2021
Results posted
Jan 16, 2026
Last update
Jun 29, 2026

Oversight

Data monitoring committee
Yes
FDA-regulated drug
Yes
FDA-regulated device
No
View the source record on ClinicalTrials.gov ↗

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This study is completed, as verified in Jun 2026. You cannot join it, but the record below documents what was studied.

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Discussion

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Studies of the drug tested here: SYN023

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