A Trial to Evaluate Safety, Tolerability, and Immune Responses of an Investigational Monovalent Chimpanzee Adenoviral Vectored Sudan Ebolavirus Vaccine in Healthy Adults

NCT06803342 | Active Not Recruiting Phase 2 DMC FDA Drug

• 2 other identifiers: Sabin-00575A50119C00055
• Study Type: interventional
• Target: 200
• Locations: 1 country
• Sites: 4

Brief Summary

A Phase 2, Randomized, Double-blind, Placebo-Controlled Trial to Evaluate Safety, Tolerability, and Immune Responses of an Investigational Monovalent Chimpanzee Adenoviral Vectored Sudan Ebolavirus Vaccine in Healthy Adults

Conditions

Ebola Sudan Virus Disease

Keywords

cAD3-Sudan Vaccine; Sudan Ebolavirus Vaccine; Sudan Ebolavirus (SUDV)

Outcome Measures

Primary Outcomes (1)

• To determine the percentage of vaccinated participants who develop SAEs, AEs, and AESI from cAd3-Sudan Vaccine and placebo

  Count and percentage of vaccinated participants who develop: - serious adverse events (SAEs), - solicited adverse events (AEs), - unsolicited AEs, - adverse event of special interest (AESI), - medically attended adverse events (MAAE), - AE at each intensity level. Estimand 1a (Primary): Count and percentage of vaccinated participants who would develop SAEs, solicited AEs, unsolicited AEs, AESI, MAAE, and AE at each intensity level will be evaluated with each treatment group. A treatment policy strategy is used for assessing safety irrespective of a current (or prior) infection at time of the vaccination. Infections and death (if the participant meet the AE and time window criteria) are included in the endpoint (composite strategy).

  1 Year

Secondary Outcomes (10)

• To determine the geometric mean concentration (GMC) of the antibody response (IgG) to cAd3-Sudan Vaccine at Day 29 post-vaccination.

  29 Days

• To determine geometric mean increase (GMI) of anti-SUDV-GP binding IgG antibodies at Day 29 post-vaccination

  29 Days

• To determine the geometric mean of the ND50 (GMND50) of anti-SUDV-GP neutralizing antibodies on Day 29 post-vaccination.

  29 Days

• To determine the geometric mean increase of the ND50 (GMIND50) of anti-SUDV-GP neutralizing antibodies at Day 29 post-vaccination.

  29 Days

• To determine the percentage of participants (and 95%CI) with seroconversion at Day 29 post-vaccination.

  29 Days

Other Outcomes (4)

• To determine cell-mediated immune response (IFN-γ secreting T cells) to cAd3-Sudan Vaccine at Day 1, Day 15, Day 29, Day 169, and Day 366 in a subset of 40 Participants

  1 year

• To determine cell-mediated immune response (CD4+ T-cells and/or CD8+ T-cells producing IFN-γ and/or IL-2 and/or TNF-α) to cAd3-Sudan Vaccine at Day 1, Day 15, Day 29, Day 169, and Day 366 in a subset of 40 Participants

  1 Year

• To determine the geometric mean concentration (GMC) of anti-SUDV-GP binding IgM antibodies at Day 1, Day 8, Day 15, and Day 29.

  29 Days

Study Arms (2)

cAd3-Sudan Vaccine (1.0 × 10^11 PU)

ACTIVE COMPARATOR

Single dose of cAd3-Sudan Vaccine (1x10\^11 PU) administered intramuscularly (IM) with needle and syringe in a volume of 0.83 mL.

Biological: cAd3-Sudan Vaccine

Placebo 0.9% NaCl solution

PLACEBO COMPARATOR

Single dose of Placebo (0.9% NaCl solution for injection) administered intramuscularly (IM) with needle and syringe in a volume of 0.83 mL.

Biological: Placebo

Interventions

cAd3-Sudan Vaccine BIOLOGICAL

The recombinant chimpanzee adenovirus Type 3-vectored Sudan Ebolavirus vaccine, (cAd3-Sudan) is composed of a cAd3 vector that expresses wild type glycoprotein (WT GP) from the Sudan Gulu ebolavirus strain.

cAd3-Sudan Vaccine (1.0 × 10^11 PU)

Placebo BIOLOGICAL

0.9% NaCl solution for injection.

Placebo 0.9% NaCl solution

Eligibility Criteria

• Age: 18 Years - 70 Years
• Sex: all
• Healthy Volunteers: Yes
• Age Groups: Adult (18-64), Older Adult (65+)

You may qualify if:

• Able and willing to complete and provide informed consent prior to any trial procedure including optional consent for retention of blood samples for potential future testing and assay development. As part of the informed consent process, the participant must complete a Test of Understanding (ToU) about the study and answer at least 90% of the questions correctly at least once in three attempts;
• Male or non-pregnant female 18 to 70 (inclusive) years of age at time of consent;
• Is capable of understanding and agrees to comply with planned trial procedures and to be available for all clinic follow-up for all planned trial visits;
• Able to provide proof of identity to the satisfaction of the trial clinician completing the enrollment process; has a means to be contacted and to contact the investigator during the trial;
• Agree not to receive any vaccine within 3 months of trial vaccination (prior and after) trial;
• Agree not to donate bone marrow, blood, or blood products until 3 months after the trial vaccination;
• In good general health without clinically significant medical conditions, based on medical history, physical examination, vital signs, and clinical laboratory results as deemed acceptable by PI;
• Clinical laboratory results within 28 days prior to vaccination within the testing laboratory reference ranges (or deemed not clinically significant by the PI) for the following parameters: White blood cells (WBC), Complete blood count (CBC), Red blood cells (RBC), Hemoglobin (HGB), total lymphocyte count, coagulation tests to include prothrombin time in terms of INR, fibrinogen, protein C, d-dimer, and chemistry tests to include alanine aminotransferase (ALT), aspartate aminotransferase (AST), and serum creatinine. A laboratory result that is outside the reference range and is deemed not clinically significant by the PI will not exclude the participant;
• Has a body mass index (BMI) \>17 and ≤ 37 at screening.
• Female participant specific criteria:
• Negative pregnancy serum test at screening, and negative urine pregnancy test before vaccination AND:
• Use of oral, implantable, transdermal or injectable contraceptives for 21 days prior to vaccination and for at least 24 weeks after vaccination, UNLESS the participant fulfills one of the following criteria:
• At least 1 year post-menopausal.
• Surgically sterile.
• Use of another reliable form of contraception must be approved by the Investigator (e.g., double barrier method, intrauterine device, contraceptive patches).

You may not qualify if:

• Participant is female and is breastfeeding or plans to become pregnant or breastfeed from trial vaccination through 24 weeks post-vaccination
• Has any medical disease or condition that, in the opinion of the investigator, precludes trial participation. This includes any acute, subacute, intermittent, or chronic medical disease or condition that would place the Participant at an unacceptable risk of injury, render the Participant unable to meet the requirements of the protocol, or may interfere with the evaluation of responses or the Participant's successful completion of the trial; (Chronic conditions that are well-controlled and medically stable, i.e. no relevant change in treatment for medical reasons occurred in the last 6 months, are allowed at the discretion of the PI, e.g. hypertension, asthma, thyroid disease) Any confirmed or suspected immunosuppressive or immunodeficient condition resulting from disease (e.g., malignancy, Human Immunodeficiency Virus \[HIV\] infection) or immunosuppressive/cytotoxic therapy (e.g., medications used during cancer chemotherapy, organ transplantation or to treat autoimmune disorders) and any infection requiring IV antibiotics or hospitalization within 90 days prior to screening.
• History of Guillain-Barré syndrome
• History of allergy to any component of the vaccine
• Serology screen positive for infectious diseases (hepatitis B, hepatitis C, HIV, Human T-cell leukemia virus (HTLV), Syphilis);
• Known prior exposure to Sudan Ebolavirus or prior diagnosis of Sudan Ebolavirus Disease, determined from the participant's reported medical history
• History of or active status of any of the following clinically significant conditions:
• Serious adverse reactions to vaccines such as anaphylaxis, urticaria (hives), respiratory difficulty, angioedema, or abdominal pain;
• Allergic reaction to excipients in the trial vaccine including gentamycin, neomycin or streptomycin;
• Diabetes mellitus Type I or Type II (even if stable)
• Tuberculosis
• Hereditary angioedema (HAE), acquired angioedema (AAE), or idiopathic forms of angioedema;
• Idiopathic urticaria within the last year
• Seizure in the past 3 years or treatment for seizure disorder in the past 3 years (even if stable);
• Asplenia or functional asplenia;

Sponsors & Collaborators

• Albert B. Sabin Vaccine Institute: lead
• Biomedical Advanced Research and Development Authority: collaborator

Study Sites (4)

Synexus Clinical Research US, Inc.

Phoenix, Arizona, 85020, United States

Location

Optimal Research; LLC

Melbourne, Florida, 32934, United States

Location

Synexus Clinical Research US, Inc.

Chicago, Illinois, 60602, United States

Location

Synexus Clinical Research US, Inc.

San Antonio, Texas, 78229, United States

Location

Study Design

• Study Type: interventional
• Phase: phase 2
• Allocation: RANDOMIZED
• Masking: QUADRUPLE
• Who Masked: PARTICIPANT, CARE PROVIDER, INVESTIGATOR, OUTCOMES ASSESSOR
• Masking Details: Sponsor
• Purpose: PREVENTION
• Intervention Model: PARALLEL
• Sponsor Type: OTHER
• Responsible Party: SPONSOR

Model Details: Participants will be randomized 4:1 to receive the cAd3-Sudan Vaccine at 1.0 × 10\^11 PU dose or placebo at Day 1.

Study Record Dates

• First Submitted: January 27, 2025
• First Posted: January 31, 2025
• Study Start: June 26, 2025
• Primary Completion (Estimated): February 1, 2027
• Study Completion (Estimated): April 1, 2027
• Last Updated: February 10, 2026

Record last verified: 2026-02

Data Sharing

• IPD Sharing: Will share
• Shared Documents: CSR
• Time Frame: The sponsor will also publish results in a manuscript in a peer reviewed journal, which requires a published study protocol. The sponsor expects this will be completed by late 2027.

Locations

US (4)