Dosage-Escalation Study of the Safety and Immunogenicity of a Novel Rabies Vaccine ChAd155-RG vs. the Comparator RABAVERT Vaccine in Healthy Adult Subjects

A Phase 1, Dosage-Escalation Study of the Safety and Immunogenicity of a Novel Rabies Vaccine ChAd155-RG vs. the Comparator RABAVERT Vaccine in Healthy Adult Subjects

This is a single-center, observer-blinded, dosage-escalation trial to evaluate the safety, tolerability, reactogenicity, and immunogenicity of ChAd155-RG compared with RABAVERT in rabies virus-naïve healthy male and non-pregnant female adult subjects ages 18-49. There are 4 dose groups: Group A will receive ChAd155-RG at the lower dosage (5x1010vp) on Day 1, then placebo injections on Days 8, 15, and 22; Group B will receive ChAd155-RG at the higher dosage (1x1011vp) on Day 1, then placebo injections on Days 8, 15, and 22; Group C will receive ChAd155-RG at the higher dosage (1x1011vp) on Days 1 and 15, and placebo injections on Days 8 and 22; Group D will receive RABAVERT at the standard dose (1 mL) on Days 1, 8, and 22, and a placebo injection on Day 15. Since this is a dosage-escalation study, sentinel subjects will be used at each dosage level before non-sentinel subjects will be enrolled. The study will be conducted at Emory University Vaccine and Treatment Evaluation Unit (VTEU). This trial is expected to take approximately 48 months to complete. The duration of each subject's participation is approximately 13 months, from recruitment through the last study visit. The primary objectives of this study are: 1) Assessment of the safety, tolerability, and reactogenicity of one dose of ChAd155-RG at 5x1010vp per dose, or one or two doses of ChAd155-RG at 1x1011vp per dose; 2) Comparison of the safety, tolerability, and reactogenicity of one or two doses of ChAd155-RG, with three doses of RABAVERT.

Study Overview

• Status: Completed
• Conditions: Rabies; Rabies Immunisation
• Intervention / Treatment: Other: Placebo; Biological: ChAd155-RG; Biological: Rabies Vaccine

Detailed Description

This is a single-center, observer-blinded, Phase 1, dosage-escalation trial to evaluate the safety, tolerability, reactogenicity, and immunogenicity of ChAd155-RG compared with RABAVERT in rabies virus-naïve healthy male and non-pregnant female adult subjects ages 18-49. Subjects who have never received a licensed or investigational rabies virus vaccine, or an Ad-based investigational vaccine, and who have never been exposed to a rabid animal will be eligible for enrollment. There are 4 dose groups: Group A will receive ChAd155-RG at the lower dosage (5x1010vp) on Day 1, then placebo injections on Days 8, 15, and 22; Group B will receive ChAd155-RG at the higher dosage (1x1011vp) on Day 1, then placebo injections on Days 8, 15, and 22; Group C will receive ChAd155-RG at the higher dosage (1x1011vp) on Days 1 and 15, and placebo injections on Days 8 and 22; Group D will receive RABAVERT at the standard dose (1 mL) on Days 1, 8, and 22, and a placebo injection on Day 15. Since this is a dosage-escalation study, sentinel subjects will be used at each dosage level before non-sentinel subjects will be enrolled. The SMC will review the available safety, reactogenicity, AE, and lab data of all the sentinel subjects, and will decide if the remaining non-sentinel subjects should be enrolled. The study will be conducted at Emory University Vaccine and Treatment Evaluation Unit (VTEU). This trial is expected to take approximately 48 months to complete. The duration of each subject's participation is approximately 13 months, from recruitment through the last study visit. The primary objectives of this study are: 1) Assessment of the safety, tolerability, and reactogenicity of one dose of ChAd155-RG at 5x1010vp per dose, or one or two doses of ChAd155-RG at 1x1011vp per dose; 2) Comparison of the safety, tolerability, and reactogenicity of one or two doses of ChAd155-RG, with three doses of RABAVERT. The secondary objective is to assess the serum rabies VNA levels by a standard, WHO-approved, RFFIT, as assessed by immune response kinetics (through approximately 12 months after first dose of vaccine), seroconversion rates, and peak GMT in each treatment arm.

• Study Type: Interventional
• Enrollment (Actual): 50
• Phase: Phase 1

Contacts and Locations

Study Locations

• United States
  • Georgia
    • Decatur, Georgia, United States, 30030-1705
      • The Hope Clinic of Emory University

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: 18 years to 49 years (Adult)
• Accepts Healthy Volunteers: Yes

Description

Inclusion Criteria:

1. Must be a male or female aged 18-49 years old (inclusive) at the time of first vaccination.
2. Must be able to provide written informed consent.
3. Must have a body mass index (BMI) = / >18.5 and <35.0 kg/m^2

4. Must be in good health based on physical examination, vital signs*, medical history, safety labs**, and the investigator's clinical judgment.

   *Vital signs must be within the normal ranges. If a subject has elevated systolic or diastolic blood pressure, subject may rest for 10 minutes in a quiet room and the blood pressure may be retaken.

   **Safety lab normal ranges will be those used by the reference clinical lab. Protocol-specific criteria for individual subjects are listed in criteria #5.

5. Must have acceptable* lab values within 28 days before enrollment. *Acceptable values include:

   • Hemoglobin: women >11.6 g/dL, men >13.1 g/dL
   • White blood cells: >3,700 but <10,900 cells/mm^3
   • Absolute neutrophil count: = / >1,500 cells/mm^3
   • Absolute lymphocyte count: = / >850 cells/mm^3
   • Platelets: >139,000 but <401,000 per mm^3
   • Urine dipstick (clean urine sample): protein <1+, glucose negative
   • Alanine transaminase and aspartate transaminase (ALT, AST) <1.1 x institutional upper limit of normal (ULN)
   • Total bilirubin <1.1x institutional ULN
   • Blood urea nitrogen (BUN) <1 x institutional ULN
   • Serum creatinine <1x institutional ULN
   • If lab screening tests are out of range, repeating them is permitted once, provided there is an alternative explanation for the out-of-range value.

6. Women of childbearing potential* must have a negative serum pregnancy test at screening and negative urine pregnancy tests within 24 hours before each vaccination.

   • Women of non-childbearing potential, defined as postmenopausal (any age with amenorrhea for = / >12 months without other known or suspected cause for amenorrhea), or surgically sterile [hysterectomy, bilateral tubal ligation, bilateral oophorectomy, or successful Essure(R) placement (permanent, non-surgical, non-hormonal sterilization)] with documented confirmation test = / >3 months after the procedure), are not required to use contraceptive methods.

7. Women of childbearing potential must use an acceptable method of contraception* from 28 days before the first vaccination until = / >60 days after the last vaccination.

   *Acceptable methods of contraception include: prescription oral contraceptives, contraceptive injections, intrauterine device (IUD), implants, vaginal ring, double-barrier method, contraceptive patch, male partner who had a vasectomy at least 6 months prior to study enrollment, abstinence (defined as refraining from heterosexual intercourse during participation in this trial [from 28 days before the first vaccination until = / >60 days after the last vaccination]).

8. Female subjects must agree to not donate eggs (ova, oocytes) from the start of screening until = / >60 days after the last vaccination.

9. Male subjects who have not had a vasectomy* and are sexually active with a woman of childbearing potential must agree to use an acceptable method of contraception**.

   *Men who have had a vasectomy must have had the procedure performed at least 6 months prior to study enrollment.

   **Acceptable methods of contraception must be used from the first vaccination until = / >60 days after the last vaccination, and include: abstinence (defined as refraining from heterosexual intercourse with a female partner of childbearing potential during participation in this trial [from 28 days before the first vaccination until = / >60 days after the last vaccination]; a double-barrier method, such as condom with spermicidal foam/gel/film/cream/suppository and partner with occlusive cap (diaphragm, cervical/vault caps); if the female partner is using an acceptable method of contraception (see Inclusion Criterion #7), a single-barrier method for the male subject is acceptable.

10. Male subjects must agree to not donate sperm from the start of screening until = / >60 days after the last vaccination.
11. Must be available and willing to participate for the duration of this trial.
12. Must have a means to be contacted by telephone.

Exclusion Criteria:

1. Was ever vaccinated with a licensed or investigational rabies vaccine* or was diagnosed with rabies exposure, infection, or disease.

   *Includes RABAVERT and Imovax. Subject's verbal history will suffice.

2. Has a higher risk than the average US resident with regard to exposure to rabies, per the Rabavert package insert and rabies vaccination recommendations from the CDC*.

   • People at high risk of exposure to rabies, such as veterinarians, animal handlers, rabies laboratory workers, spelunkers, and rabies biologics production workers.
   • People whose activities bring them into frequent contact with rabies virus or with possibly rabid animals.
   • International travelers who are likely to come in contact with animals in parts of the world where rabies is common.
3. Was ever vaccinated with a licensed or investigational Ad vector or Ad vaccine.
4. Is currently taking chloroquine or hydroxychloroquine.
5. Was diagnosed with laboratory-confirmed COVID-19 (PCR or antigen-based test) in the preceding 28 days.
6. Positive serology for HIV antibody, HCV antibody, or Hepatitis B surface antigen (HBsAg).

7. Has known allergy or history of anaphylaxis or other serious adverse reaction to a vaccine or vaccine products*.

   *Including egg products, aminoglycosides, gelatin, sorbitol, tris (hydroxymethyl)-amino methane (THAM), or any of the constituents of the study vaccines.

8. Has severe allergy or anaphylaxis to latex.

9. Has an acute illness or temperature = / >38.0 Degrees Celsius on Day 1*.

   *Subjects with fever or acute illness on the day of vaccination may be re-assessed and enrolled if healthy or only minor residual symptoms remain within 3 days.

10. Female subjects who are pregnant or breastfeeding, or planning to become pregnant while enrolled in this trial and at least 60 days after last vaccination.
11. Has history of autoimmune disease, or clinically significant cardiac, pulmonary, hepatic, rheumatologic, or renal disease by history, physical examination, and/or lab studies.

12. Has history of malignancy other than squamous cell or basal cell skin cancer, unless there has been surgical excision that is considered to have achieved cure*.

    *Subjects with a history of skin cancer must not be vaccinated at the previous tumor site.

13. Has known or suspected congenital or acquired immunodeficiency, or recent history or current use of immunosuppressive therapy*.

    *Anti-cancer chemotherapy or radiation therapy within the preceding 6 months, or long-term (= / >2 weeks within the previous 3 months) systemic corticosteroid therapy (at a dosage of = / >0.5 mg/kg/day). Intranasal or topical prednisone (or equivalent) are allowed.

14. Is post-organ and/or stem cell transplant, whether or not on chronic immunosuppressive therapy.
15. Had major surgery (per the investigator's judgment) within 4 weeks before study entry or planned major surgery during this trial.

16. Has history of diabetes mellitus type 1 or type 2, including cases controlled with diet alone.

    *Note: history of isolated gestational diabetes is not an exclusion criterion.

17. Has history of thyroidectomy, or thyroid disease requiring medication in the last 12 months.

18. Has history of hypertension, even if medically controlled.

    *Note: Vital signs must be normal by protocol toxicity grading scale. In the event of an abnormal heart rate or blood pressure due to physiological variation or activity, the subject may rest for 10 minutes in a quiet room, and then blood pressure and/or heart rate re-measured. Repeated vital signs may be used to determine eligibility.

19. Received live attenuated vaccines from 30 days before first vaccination until 30 days after final vaccination*.

    *Not including licensed or authorized COVID-19 vaccines.

20. Received killed or inactivated vaccines from 14 days before first vaccination until 30 days after final vaccination*.

    *Not including licensed COVID-19 vaccines

21. Received experimental therapeutic agents within 3 months before first vaccination or plans to receive any experimental therapeutic agents during this trial*.

    *That that in the opinion of the investigator would interfere with safety or immunogenicity assessments.

22. Is currently participating or plans to participate in another clinical study which would involve receipt of the following:*

    * An investigational product, blood drawing, or an invasive medical procedure that would require administration of anesthetics, intravenous (IV) dyes, or removal of tissue during this trial and, in the opinion of the investigator, would interfere with safety or immunogenicity assessments.

    -Includes endoscopy, bronchoscopy, and administration of IV contrast.

23. Received blood products or immunoglobulin in the 3 months before study entry or planned use during this trial.
24. Donated a unit of blood or blood products within 8 weeks before Day 1 or plans to donate blood or blood products during this trial.
25. Has major psychiatric illness in the past 12 months that in the opinion of the investigator would preclude participation.
26. Has current alcohol use or current or past abuse of recreational or narcotic drugs by history as judged by the investigator to potentially interfere with study adherence.
27. Has a history of chronic urticaria.
28. Has tattoos, scars, or other marks on both deltoid areas which would, in the opinion of the investigator, interfere with assessment of the vaccination site.

29. Is a site employee* or staff who are paid entirely or partially by/through the OCRR contract for this trial, or staff who are supervised by the Principal Investigator (PI) or sub-investigators.

    *Including the PI, sub-investigators listed on Form FDA 1572 or Investigator of Record Form.

30. In the opinion of the investigator cannot communicate reliably, is unlikely to adhere to the requirements of this trial, or has any condition which would limit the ability to complete this trial.
31. Has history of Guillain-Barre syndrome, meningitis, encephalitis, neuroparalysis, transient paralysis, myelitis, retrobulbar neuritis, multiple sclerosis, vertigo, or visual disturbances.
32. Has a history of arterial or venous thrombosis, or thrombocytopenia that required medical attention.

Study Plan

How is the study designed?

Design Details

• Primary Purpose: Prevention
• Allocation: Randomized
• Interventional Model: Sequential Assignment
• Masking: Double

Number of Arms

4

Arms and Interventions

Participant Group / Arm	Intervention / Treatment
Experimental: Arm A; One dose (1 ml (5x10^10 vp)) of ChAd155-RG vaccine administered intramuscularly on Day 1, and 1 ml of matching placebo administered intramuscularly on Days 8, 15, 22. N=14 (3 sentinel, 11 non-sentinel)	Other: Placebo; 0.9% Sodium Chloride, USP injection.; Biological: ChAd155-RG; The ChAd155-RG Vaccine consists of a replication-defective group C ChAd, ChAd155, expressing RG under the control of the CMV promoter. The RG sequence cloned into the ChAd155 vector is a medoid, a natural viral strain with the highest average percent of amino acid identity among all RG sequences annotated in the NCBI database. The selected RG (NCBI strain AGN94271) shares an average 94% percent identity to the RGs in current vaccines.
Experimental: Arm B; One dose (1 ml (1x10^11 vp)) of ChAd155-RG vaccine administered intramuscularly on Day 1, and 1 ml of matching placebo administered intramuscularly on Days 8, 15, 22. N=14 (3 sentinel, 11 non-sentinel)	Other: Placebo; 0.9% Sodium Chloride, USP injection.; Biological: ChAd155-RG; The ChAd155-RG Vaccine consists of a replication-defective group C ChAd, ChAd155, expressing RG under the control of the CMV promoter. The RG sequence cloned into the ChAd155 vector is a medoid, a natural viral strain with the highest average percent of amino acid identity among all RG sequences annotated in the NCBI database. The selected RG (NCBI strain AGN94271) shares an average 94% percent identity to the RGs in current vaccines.
Experimental: Arm C; Two doses (1 ml (1x10^11 vp) each) of ChAd155-RG vaccine administered intramuscularly on Day 1 (first dose) and Day 15 (second dose), and 1 ml of matching placebo administered intramuscularly on Days 8 and 22. N=10	Other: Placebo; 0.9% Sodium Chloride, USP injection.; Biological: ChAd155-RG; The ChAd155-RG Vaccine consists of a replication-defective group C ChAd, ChAd155, expressing RG under the control of the CMV promoter. The RG sequence cloned into the ChAd155 vector is a medoid, a natural viral strain with the highest average percent of amino acid identity among all RG sequences annotated in the NCBI database. The selected RG (NCBI strain AGN94271) shares an average 94% percent identity to the RGs in current vaccines.
Active Comparator: Arm D; Three doses (1 ml each) of RABAVERT vaccine administered intramuscularly on Day 1 (first dose), Day 8 (second dose), and Day 22 (third dose), and 1 ml of matching placebo administered intramuscularly on Day 15. N=12 (2 sentinel, 10 non-sentinel)	Other: Placebo; 0.9% Sodium Chloride, USP injection.; Biological: Rabies Vaccine; The RABAVERT Vaccine is an inactivated, purified chick embryo cell vaccine (PCECV). It consists of lyophilized rabies virus (strain Flury LEP) that has been propagated in chicken fibroblasts, inactivated with beta-propiolactone, and concentrated and purified by centrifugation

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Number and Percentage of Participants With Solicited Injection Site Reactogenicity Events in Each Treatment Arm and Overall	Injection site reactogenicity events were solicited on a memory aid completed by participants from the time of each vaccination through Day 7 following each vaccination. Injection site reactogenicity events included pruritus, erythema, ecchymosis, induration/swelling, pain, and tenderness. Each event was graded as mild, moderate, or severe. Participants are counted according to their maximum severity of injection site event reported. Participants reporting no injection site events are counted under "None".	Day 1 through Day 29
Number and Percentage of Participants With Solicited Systemic Reactogenicity Events in Each Treatment Arm and Overall	Systemic reactogenicity events were solicited on a memory aid completed by participants from the time of each vaccination through Day 7 following each vaccination. Systemic reactogenicity events included fever, chills/shivering/sweating, fatigue, malaise, myalgia and arthralgia (exclusive of the injection site), headache, and nausea. Each event was graded as mild, moderate, or severe. Participants are counted according to their maximum severity of systemic event reported. Participants reporting no systemic events are counted under "None".	Day 1 through Day 29
Number and Percentage of Participants With Serious Adverse Events (SAEs) Considered Study Vaccine-Related in Each Treatment Arm and Overall	An AE or suspected AE was considered "serious" if, in the view of either the investigator or sponsor, it resulted in any of the following outcomes: death, a life-threatening AE, inpatient hospitalization or prolongation of existing hospitalization, a persistent or significant incapacity or substantial disruption of the ability to conduct normal life functions, or a congenital anomaly/birth defect. Events were determined to be related if there was a reasonable possibility that the study product caused the AE; that is, there was evidence to suggest a causal relationship between the study product and the AE. Each event was graded as mild, moderate, or severe. Participants are counted according to their maximum severity of event reported. Participants reporting no vaccine-related SAEs are counted under "None".	Day 1 through Day 381
Number and Percentage of Participants With Study Vaccine-related Lab Adverse Events (AEs) in Each Treatment Arm and Overall	Clinical safety lab parameters evaluated after receipt of vaccine (on Days 2, 8, 16, and Day 22) included WBCs, hemoglobin, platelets, absolute neutrophil count, absolute lymphocyte count, ALT, AST, total bilirubin, BUN, and creatinine. Lab events were assessed for relatedness and were determined to be related if there was a reasonable possibility that the study product caused the AE; that is, there was evidence to suggest a causal relationship between the study product and the AE. Each lab event was graded as mild, moderate, or severe. Participants are counted according to their maximum severity of event reported. Participants reporting no lab events are counted under "None".	Day 1 through Day 22
Number and Percentage of Participants With Unsolicited Study Vaccine-related Adverse Events (AEs) in Each Treatment Arm and Overall	Adverse events were defined as any untoward medical occurrence in a patient or clinical investigation participant administered a study product regardless of its causal relationship to the study product administration. Unsolicited, non-serious AEs were collected from participants from Day 1 through Day 28 after the last vaccination (Day 50). Events were determined to be related if there was a reasonable possibility that the study product caused the AE; that is, there was evidence to suggest a causal relationship between the study product and the AE. Each event was graded as mild, moderate, or severe. Participants are counted according to their maximum severity of event reported. Participants reporting no vaccine-related AEs are counted under "None".	Day 1 through Day 50
Number and Percentage of Participants With New Onset of a Chronic Medical Condition in Each Treatment Arm and Overall	Participants were queried at each visit for the occurrence of new onset chronic medical conditions throughout the duration of the study.	Day 1 through Day 381
Number and Percentage of Participants With Serious Adverse Events (SAEs) in Each Treatment Arm and Overall	An AE or suspected AE was considered "serious" if, in the view of either the investigator or sponsor, it resulted in any of the following outcomes: death, a life-threatening AE, inpatient hospitalization or prolongation of existing hospitalization, a persistent or significant incapacity or substantial disruption of the ability to conduct normal life functions, or a congenital anomaly/birth defect. Each event was graded as mild, moderate, or severe. Participants are counted according to their maximum severity of event reported. Participants reporting no SAEs are counted under "None".	Day 1 through Day 381

Secondary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Percentage of Participants Seroconverting to Rabies Virus in Each Treatment Arm and Overall	Serum samples for rabies VNA were collected prior to vaccination (Day 1) and on Day 8, Day 15, Day 22, Day 29, Day 91, Day 181, and Day 381. Results from the rabies VNA RFFIT assay were reported in IU/mL, with a typical range of 1-15 IU/mL. Results beyond 15 IU/mL required dilution and retesting per the lab's standard operating procedures. The lower limit of quantification for the RFFIT assay is 0.1 IU/mL; values below the LLOQ were imputed as 1/2 the LLOQ, or 0.05 IU/mL. Seroconverting to rabies virus is defined as VNA concentration =0.5 IU/mL post-vaccination.	Day 8, Day 15, Day 22, Day 29, Day 91, Day 181, and Day 381
Rabies VNA Geometric Mean Titer	Serum samples for rabies VNA were collected prior to vaccination (Day 1) and on Day 8, Day 15, Day 22, Day 29, Day 91, Day 181, and Day 381. Results from the rabies VNA RFFIT assay were reported in IU/mL, with a typical range of 1-15 IU/mL. Results beyond 15 IU/mL required dilution and retesting per the lab's standard operating procedures. The lower limit of quantification for the RFFIT assay is 0.1 IU/mL; values below the LLOQ were imputed as 1/2 the LLOQ, or 0.05 IU/mL. The geometric mean titer was calculated for each study arm at each immunogenicity time point.	Day 1, Day 8, Day 15, Day 22, Day 29, Day 91, Day 181, and Day 381
Peak Rabies VNA Geometric Mean Titer	Serum samples for rabies VNA were collected prior to vaccination (Day 1) and on Day 8, Day 15, Day 22, Day 29, Day 91, Day 181, and Day 381. Results from the rabies VNA RFFIT assay were reported in IU/mL, with a typical range of 1-15 IU/mL. Results beyond 15 IU/mL required dilution and retesting per the lab's standard operating procedures. The lower limit of quantification for the RFFIT assay is 0.1 IU/mL; values below the LLOQ were imputed as 1/2 the LLOQ, or 0.05 IU/mL. Peak geometric mean titer was defined for each study arm as the geometric mean of the highest titer per participant across all post-vaccination antibody timepoints.	Day 8 through Day 381

Collaborators and Investigators

• Sponsor: National Institute of Allergy and Infectious Diseases (NIAID)

Study record dates

Study Major Dates

• Study Start (Actual): September 19, 2019
• Primary Completion (Actual): March 24, 2023
• Study Completion (Actual): March 24, 2023

Study Registration Dates

• First Submitted: July 11, 2019
• First Submitted That Met QC Criteria: July 11, 2019
• First Posted (Actual): July 15, 2019

Study Record Updates

• Last Update Posted (Actual): April 10, 2024
• Last Update Submitted That Met QC Criteria: March 14, 2024
• Last Verified: July 5, 2019

More Information

Terms related to this study

• Keywords: Safety; Vaccine; Adults; Healthy; Immunogenicity; Rabies; ChAd155-RG; Dosage-Escalation; RABAVERT
• Additional Relevant MeSH Terms: RNA Virus Infections; Virus Diseases; Infections; Mononegavirales Infections; Rhabdoviridae Infections; Rabies
• Other Study ID Numbers: 17-0089; HHSN272201300018I

Drug and device information, study documents

• Studies a U.S. FDA-regulated drug product: Yes
• Studies a U.S. FDA-regulated device product: No
• product manufactured in and exported from the U.S.: No