Ebola Sudan Chimpanzee Adenovirus Vector Vaccine in Healthy Adults

Phase 1

Completed

• Conditions: Ebola Virus
• Interventions: Biological: cAd3-EBO S vaccine

• Registration Number: NCT04041570
• Lead Sponsor: National Institute of Allergy and Infectious Diseases (NIAID)

Brief Summary

RV 508 was a Phase I, open-label, dose-escalation study to examine the safety, tolerability and immunogenicity of an investigational Ebola vaccine in healthy adults. VRC-EBOADC086-00-VP, a chimpanzee adenovirus serotype 3 vector-based Ebola vaccine, encodes wild type (WT) glycoprotein (GP) from the Sudan strain of Ebolavirus and is administered intramuscularly (IM).

Detailed Description

A total of 40 participants were evenly split, with 20 in each of the two dosage groups to receive the investigational cAd3-EBO S vaccine at a dose of either 1x10\^10 particle units (PU) (Group 1) or 1x10\^11 PU (Group 2). The dose escalation plan included daily review of any new safety data by a study clinician, regular review of safety data by the protocol team and a staged enrollment plan with required interim safety reviews. The study began with enrollment of 3 participants into Group 1 (1x10\^10 PU) at a rate of 1 participant per day. After at least 7 days of follow-up for the first 3 vaccinated participants, an interim safety review occurred before enrollment of additional participants into the group. No safety issues were identified; therefore, an additional 17 participants were enrolled to complete Group 1. When there was a minimum of seven days of follow-up safety data from the last enrolled participant in Group 1, an interim safety review occurred. No safety issues were identified, and enrollment of participants into the next dose level (Group 2) began with the enrollment of 3 participants at a rate of 1 participant per day. After at least 7 days of follow-up for the first 3 vaccinated participants in Group 2 (1x10\^11 PU), an interim safety review occurred before the enrollment of additional participants into Group 2. No safety issues were identified, and an additional 17 participants were enrolled to complete Group 2. Participants were followed for approximately 48 weeks.

Study Timeline

• Study Start: 2019-07-02
• Study First Submitted: 2019-07-25
• Study First Submitted QC: 2019-07-30
• Study First Posted: 2019-08-01
• Primary Completion: 2020-09-07
• Study Completion: 2020-09-07
• Results First Submitted: 2021-09-07
• Results First Submitted QC: 2021-10-27
• Results First Posted: 2021-11-24
• Status Verified: 2022-11
• Last Update Submitted: 2022-11-10
• Last Update Posted: 2022-12-06

Recruitment & Eligibility

• Status: COMPLETED
• Sex: All
• Target Recruitment: 40

Inclusion Criteria

1. 18 to 50 years old.

2. Available for clinical follow-up through Week 48 after enrollment.

3. Able to provide proof of identity to the satisfaction of the study clinician completing the enrollment process.

4. Able and willing to provide fingerprints and have their photographs taken including injection site photographs.

5. Must allow home visits

6. Must complete an Assessment of Understanding (AoU) prior to enrollment by answering 9 out of 10 questions at least once in 3 attempts.

7. Able to read (English or Luganda) and willing to complete the informed consent process.

8. In good general health without clinically significant medical history.

9. Physical examination and laboratory results without clinically significant findings and a body mass index (BMI) ≤ 40 within the 56 days prior to enrollment.

10. Laboratory Criteria within 56 days prior to enrollment:

    1. Hemoglobin ≥ 11.0 g/dL for women; ≥12.5 g/dL for men.
    2. White blood cells (WBC) = 2,500-12,000 cells/mm^3.
    3. Total lymphocyte count ≥ 800 cells/mm^3.
    4. Platelets = 125,000 - 400,000/mm^3.
    5. Alanine aminotransferase (ALT) ≤ 1.25 x upper limit of normal.
    6. Serum creatinine ≤ 1 x upper limit of normal.
    7. HIV-uninfected as evidenced by a negative FDA-approved HIV diagnostic test.

    Female-Specific Criteria:

11. Negative β-HCG (human chorionic gonadotropin) pregnancy test; serum β-HCG at screening and urine β-HCG at enrollment if woman is of reproductive potential.

12. Agrees to use an effective means of birth control from at least 21 days prior to enrollment through 24 weeks after study vaccination if assessed to be of reproductive potential.

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Exclusion Criteria

Volunteer has received any of the following substances:

1. Investigational Ebola or Marburg vaccine in a prior clinical trial or prior receipt of a cAd3 adenoviral vectored investigational vaccine.

2. Chronic use of immunomodulators and systemic glucocorticoids in daily doses of glucocorticoid equivalence > 20 mg of prednisolone, for periods exceeding 10 days. Non-steroidal anti-inflammatory drugs [NSAIDS] are permitted. Participants that have used less than the stated glucocorticoid dose may still be excluded at the Investigator's discretion.

3. Blood products within 112 days (16 weeks) prior to enrollment.

4. Investigational research agents within 28 days (4 weeks) prior to enrollment.

5. Live attenuated vaccines within 28 days (4 weeks) prior to enrollment.

6. Subunit or killed vaccines within 14 days (2 weeks) prior to enrollment.

7. Current anti-tuberculosis prophylaxis or therapy.

   Female-specific criteria:

8. Woman who is pregnant, breast-feeding or planning to become pregnant during the first 24 weeks after study vaccine administration.

   Volunteer has a history of any of the following clinically significant conditions:

9. Serious adverse reactions to vaccines such as anaphylaxis, urticaria (hives), respiratory difficulty, angioedema, or abdominal pain.

10. Allergic reaction to excipients in the study vaccine including gentamycin, neomycin or streptomycin.

11. Clinically significant autoimmune disease or immunodeficiency.

12. Asthma that is not well controlled.

13. Positive result on a rapid plasma reagin (RPR) test.

14. Diabetes mellitus (type I or II).

15. Thyroid disease that is not well controlled.

16. A history of hereditary angioedema (HAE), acquired angioedema (AAE), or idiopathic forms of angioedema.

17. Idiopathic urticaria within the last 1 year.

18. Hypertension that is not well controlled.

19. Bleeding disorder diagnosed by a doctor (e.g. factor deficiency, coagulopathy, or platelet disorder requiring special precautions) or significant bruising or bleeding difficulties with IM injections or blood draws.

20. A malignancy that is active, currently being treated, or not surgically cured.

21. Seizure in the past 3 years or treatment for seizure disorder in the past 3 years.

22. Asplenia or functional asplenia.

23. Psychiatric condition that precludes compliance with the protocol; past or present psychoses; or within five years prior to enrollment, history of a suicide plan or attempt.

24. Any medical, psychiatric, social condition, occupational reason or other responsibility that, in the judgment of the investigator, is a contraindication to protocol participation or impairs a volunteer's ability to give informed consent.

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Study & Design

• Study Type: INTERVENTIONAL
• Study Design: SEQUENTIAL

Arm && Interventions

Group	Intervention	Description
Group 1: cAd3-EBO S vaccine (1x10^10 PU)	cAd3-EBO S vaccine	cAd3-EBO S vaccine (1x10\^10 PU) administered intramuscularly (IM) with needle and syringe in a volume of 1 mL
Group 2: cAd3-EBO S vaccine (1x10^11 PU)	cAd3-EBO S vaccine	cAd3-EBO S vaccine (1x10\^11 PU) administered IM with needle and syringe in a volume of 1 mL

Primary Outcome Measures

Name	Time	Method
Number of Participants Reporting Local Reactogenicity Signs and Symptoms for 7 Days After the cAd3-EBO S Vaccine Administration	7 days after study product administration	Participants recorded the occurrence of solicited symptoms on a diary card for 7 days after the study product administration and reviewed the diary card with clinic staff at a follow up visit. Participants were counted once for each symptom at the worst severity if they indicated experiencing the symptom more than one time at any severity during the reporting period. The number reported for "Any Local Symptom" is the number of participants reporting any local symptom at the worst severity. Reactogenicity grading (Mild, Moderate, Severe) was done using the Toxicity Grading Scale for Healthy Adult and Adolescent Volunteers Enrolled in Preventive Vaccine Clinical Trials, modified from FDA Guidance - September 2007.
Number of Participants With Serious Adverse Events (SAEs)	Through 48 weeks after study product administration	SAEs were recorded from receipt of the study product administration through the last expected study visit at Week 48. The relationship between a SAE and the study product was assessed by the investigator based on clinical judgment and the definitions outlined in the protocol. A participant with multiple experiences of the same event is counted once using the event of worst severity.
Number of Participants With One or More Unsolicited Non-Serious Adverse Events (AEs)	Through 28 days after study product administration	Unsolicited AEs and attribution assessments were recorded in the study database from receipt of the study product administration through the visit scheduled for 28 days after study product administration. At other time periods greater than 28 days after the study product administration, only serious AEs (SAEs reported as a separate outcome and in the AE module), and new chronic medical conditions that required ongoing medical management were recorded through the last study visit. The relationship between an AE and the study product was assessed by the investigator based on clinical judgment and the definitions outlined in the protocol. A participant with multiple experiences of the same event is counted once using the event of worst severity.
Number of Participants Reporting Systemic Reactogenicity Signs and Symptoms for 7 Days After the cAd3-EBO S Vaccine Administration	7 days after study product administration	Participants recorded the occurrence of solicited symptoms on a diary card for 7 days after the study product administration and reviewed the diary card with clinic staff at a follow up visit. Participants were counted once for each symptom at the worst severity if they indicated experiencing the symptom more than one time at any severity during the reporting period. The number reported for "Any Systemic Symptom" is the number of participants reporting any systemic symptom at the worst severity. The majority of the reactogenicity grading (Mild, Moderate, Severe) was done using the Toxicity Grading Scale for Healthy Adult and Adolescent Volunteers Enrolled in Preventive Vaccine Clinical Trials, modified from FDA Guidance - September 2007. The Division of AIDS AE Grading Table, Corrected Version 2.1 was used to grade reported events of joint pain (arthralgia).
Total Number of Participants Reporting Any Reactogenicity Signs and Symptoms for 7 Days After the cAd3-EBO S Vaccine Administration	7 days after study product administration	Participants recorded the occurrence of solicited symptoms on a diary card for 7 days after the study product administration.
Number of Participants With Abnormal Laboratory Measures of Safety	Through 48 weeks after study product administration	Any abnormal laboratory results recorded as unsolicited AEs are summarized. Labs included hematology (hemoglobin, hemoglobin change from baseline, hematocrit percent, mean corpuscular volume (MCV), platelets, and white blood cell (WBC), red blood cell (RBC) and lymphocyte counts) and chemistry (alanine aminotransferase (ALT) and creatinine). Complete blood count (CBC) with total lymphocyte count results were collected at screening (≤ 56 days before enrollment), Day 0 prior to study product administration (baseline), Day 3, and Weeks 2, 4, 8 and 24. Creatinine and ALT results were collected at screening, Day 0, Day 3 and Weeks 2, 4 and 8. Institutional laboratory normal ranges as well as the Toxicity Grading Scale for Healthy Adult and Adolescent Volunteers Enrolled in Preventative Vaccine Clinical Trials, modified from FDA Guidance-September 2007 were used. Neutrophil results were not collected in the study database but were captured in the subject's laboratory results documentation.

Secondary Outcome Measures

Name	Time	Method
Baseline-subtracted Geometric Mean Titers of cAd3-EBO S Antibodies After the cAd3-EBO S Vaccine Administration	Through 28 days after study product administration	Baseline (Day 0)-subtracted geometric mean titer (GMT) was calculated along with 95% confidence intervals at Week 4 for each dose group.
Percentage of Participants With Positive Ebola-specific T Cell Responses After the cAd3-EBO S Vaccine Administration	Through 28 days after study product administration	T cell response was measured by Intracellular Cytokine Staining (ICS) assays using Peripheral Blood Mononuclear Cells (PBMCs) at 4 weeks after vaccination. The percentage of participants with T cell responses with Clopper-Pearson 95% Confidence Intervals are presented. Positivity is defined as a response over calculated thresholds determined by the trial statistician.
Geometric Mean Titers of Antibodies to the Recombinant Chimpanzee Adenovirus Serotype 3 (cAd3) Vector at 28 Days After the cAd3-EBO S Vaccine Administration	Through 28 days after study product administration	Vaccine-induced, cAd3-specific antibody responses as measured by neutralization assay. Participant blood samples were tested for cAd3-specific neutralizing activity, prior to and following vaccination, using a luciferase reporter gene virus neutralization assay as previously described (Clin Vaccine Immunol 2014; 21:783-6, References Section).
Percentage of Participants With a Positive Ebola-Specific Antibody Response After the cAd3-EBO S Vaccine Administration	Through 28 days after study product administration	A positive response is defined as a significant increase in the ELISA titer post vaccination (Week 4) compared to baseline. For each participant, a t-test was performed to compare the post vaccination titers versus those at baseline. A participant is defined as a positive responder if the one-sided t-test has a p-value \< 0.05.
Magnitude of T Cell Response as a Percentage of EBO S-specific T Cell Subset After the cAd3-EBO S Vaccine Administration	Through 28 days after study product administration	Median and interquartile ranges presented for percentage of EBO S-specific CD4 and CD8 memory T cells based on cytokine production at Week 4 for each dose group.

Trial Locations

Locations (1)

Makerere University-Walter Reed Project; 🇺🇬 Kampala, Uganda