Pan African Clinical Trials Registry
South African Medical Research Council, South African Cochrane Centre
PO Box 19070, Tygerberg, 7505, South Africa
Telephone: +27 21 938 0835 or +27 21 938 0967
Email: pactradmin@mrc.ac.za Website: pactr.samrc.ac.za
Trial no.: PACTR202512762754420 Date of Registration: 08/12/2025
Trial Status: Registered in accordance with WHO and ICMJE standards
TRIAL DESCRIPTION
Public title A Two-Cohort Phase 2, Rapid Response, Open-Label, Randomized Study to Assess Safety, Efficacy and Immunogenicity of an Investigational Monovalent Chimpanzee Adenoviral-Vectored Marburg Virus Vaccine in Adults in an Outbreak Setting
Official scientific title A Two-Cohort Phase 2, Rapid Response, Open-Label, Randomized Study to Assess Safety, Efficacy and Immunogenicity of an Investigational Monovalent Chimpanzee Adenoviral-Vectored Marburg Virus Vaccine in Adults in an Outbreak Setting
Brief summary describing the background and objectives of the trial Currently there are no approved vaccines or therapeutics to treat individuals infected with MARV. Previous studies have evaluated the safety and immunogenicity of the cAd3-Marburg vaccine in a small group of healthy adults up to 50 years of age in the United States (US) (NCT04723602). In the first Phase 2 trial, safety was assessed in 125 adults up to 70 years of age at sites within Uganda and Kenya with immunogenicity analyses in progress (NCT05817422). In the second trial, safety was assessed in 1,708 subjects in an outbreak-response trial in Rwanda where samples from 689+ participants were collected and are pending immunogenicity analyses. The third trial being conducted in 200 adults up to 70 years at multiple sites within the United States is fully enrolled with safety and immunogenicity data being collected. Ethiopia has recently declared an outbreak of MARV and, as of November 5th, 2025, there were 5 laboratory confirmed MARV cases, of whom 3 patients died, and 2 are in isolation and treatment. Daily updates on the outbreak are provided by the Ethiopian MoH. The purpose of this study is to describe the safety, efficacy, and immune response of cAd3-Marburg vaccine during the early stages of a Marburg outbreak in Ethiopia in two cohorts. This trial mirrors and takes advantage of lessons-learned from the cAd3-Marburg trial in response to the 2024 Rwanda Marburg outbreak. Primary Objective To describe the safety and tolerability of cAd3-Marburg vaccine Secondary Objectives To determine the immunogenicity of the cAd3-Marburg vaccine at Study Day 29 and Day 91 To estimate vaccine efficacy: To assess the effect of cAd3-Marburg vaccine between Study Day 11 to Day 22 (days 11 to 21 post vaccination) on the rate of virologically confirmed MVD, regardless of severity
Type of trial CCT
Acronym (If the trial has an acronym then please provide)
Disease(s) or condition(s) being studied Infections and Infestations
Sub-Disease(s) or condition(s) being studied Marburg Virus Disease
Purpose of the trial Prevention: Vaccines
Anticipated trial start date 04/12/2025
Actual trial start date 07/12/2025
Anticipated date of last follow up 30/11/2026
Actual Last follow-up date
Anticipated target sample size (number of participants) 5650
Actual target sample size (number of participants)
Recruitment status Completed
Publication URL
Secondary Ids Issuing authority/Trial register
STUDY DESIGN
Intervention assignment Allocation to intervention If randomised, describe how the allocation sequence was generated Describe how the allocation sequence/code was concealed from the person allocating the participants to the intervention arms Masking If masking / blinding was used
Factorial: participants randomly allocated to either no, one, some or all interventions simultaneously Randomised Simple randomization using a randomization table created by a computer software program Allocation was determined by the holder of the sequence who is situated off site Open-label(Masking Not Used)
INTERVENTIONS
Intervention type Intervention name Dose Duration Intervention description Group size Nature of control
Experimental Group cAd3 Marburg vaccine 1.0 × 10 (11) Particle Unit does on day 1 Once on Day 1 Cohort A Adult participants aged 18 years and above to receive cAd3-Marburg vaccine 650
Experimental Group cAd3 Marburg vaccine 1.0 × 10 (11) Particle Unit Day 1 or Day 22 Cohort B Adult participants aged 18 years and above to receive cAd3-Marburg vaccine 5000
Control Group Not applicable Not applicable Not applicable Not applicable 0 Placebo
ELIGIBILITY CRITERIA
List inclusion criteria List exclusion criteria Age Category Minimum age Maximum age Gender
Each participant must meet all of the following criteria to be enrolled in this study: 1. Male and non-pregnant female participants ≥18 years who are able and willing to complete and provide written informed consent prior to any study procedure. Note: Participants can be enrolled even if they do not provide optional consent for retention of blood samples for potential future testing and assay development. 2. Is capable of understanding and agrees to comply with planned study procedures and to be available for all clinic follow-up for all planned study visits. 3. Able to provide proof of identity to the satisfaction of the study clinician, completing the enrollment process. 4. Has a means to be contacted and to contact the investigator during the study. 5. Agree not to receive any vaccine within 28 days from study vaccination (prior and after) 6. Agree not to donate bone marrow, blood, or blood products until 3 months after the study vaccination. 7. 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 the principal investigator. Participants meeting any of the following criteria will be excluded from the study: 1. Pregnant or lactating female or plans to become pregnant or breastfeed 2. Has any medical disease or condition that, in the opinion of the investigator, precludes study participation. 3. Known prior diagnosis of MVD, including active Marburg infection, determined from the participant’s reported medical history. 4. History of or active status of any of the following clinically significant conditions: • Serious adverse reactions to vaccines • Allergic reaction to excipients in the IP • History of Diabetes mellitus Type I or Type II • Active Tuberculosis. • Hereditary angioedema, acquired angioedema, or idiopathic forms of angioedema. • Idiopathic urticaria within the last year • Bleeding disorder diagnosed by a doctor or use of anticoagulant medications • Major thrombotic event or heparin-induced thrombocytopenia or vaccine-induced thrombotic thrombocytopenia (VITT) • History of malignancy of any organ system, treated or untreated, within the past 5 years from screening. 5. Has a clinically significant acute illness (this does not include minor illnesses) or temperature ≥38.0°Celsius (≥100.4°Fahrenheit) within 24 hours of the planned dose of IP 6. Receipt of any of the following substances: • Received an investigational vaccine or drug 28 days before, during and after the planned administration of the first dose of IP. • Receipt of remdesivir within 6 days prior to receipt of IP • Use of immunomodulators or systemic glucocorticoids in daily doses of glucocorticoid equivalence >20 mg of prednisolone in the last 90 days, and for periods exceeding 10 days. Nonsteroidal anti-inflammatory drugs are permitted. • Receipt of blood products within 3 months prior to enrollment. 7. Current anti-tuberculosis prophylaxis or therapy. 8. Abnormality or permanent body art in deltoid region that would interfere with ability to observe or assess injection site reactions. 80 and over: 80+ Year,Adolescent: 13 Year(s)-17 Year(s),Adult: 18 Year(s)-44 Year(s),Aged: 65 Year(s)-79 Year(s),Middle Aged: 45 Year(s)-64 Year(s) 18 Year(s) 100 Year(s) Both
ETHICS APPROVAL
Has the study received appropriate ethics committee approval Date the study will be submitted for approval Date of approval Name of the ethics committee
Yes 02/01/2026 AHRI ALERT Ethics Review Committee AAERC
Ethics Committee Address
Street address City Postal code Country
Jimma Road, ALERT Compound P.O. Box 1005 Addis Ababa, Ethiopia Addis Ababa 00000 Ethiopia
OUTCOMES
Type of outcome Outcome Timepoint(s) at which outcome measured
Primary Outcome Count and percentage of vaccinated participants who develop: • SAEs, • solicited AEs, • unsolicited AEs, • AESI, • MAAE, • AE at each intensity level Count and percentage of vaccinated participants who would develop SAEs, solicited AEs, unsolicited AEs, AESI, MAAE, and AE at each intensity level will be described for the cohort. 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 they meet the AE and time window criteria) are included in the endpoint (composite strategy). D4 D8 D15 D29 D91
Secondary Outcome Quantitate antibody titers evolution from Study Day 1 to Day 29 to Day 91 (anti-Marburg antibodies) in Cohort A participants Day 1 to Day 29 to Day 91
Secondary Outcome New cases of MVD are ascertained through active surveillance and case detection reports through the national MVD surveillance system. Day 11 to Day 22 - days 10 to 21 post vaccination
Secondary Outcome All Cohort B participants will contribute to efficacy analysis assessed between Study Day 10 to Day 22, group receiving cAd3-Marburg on Study Day 1 will be compared to group receiving cAd3-Marburg on Study Day 22. Select Cohort A participants may be described in efficacy analysis as appropriate. Day 11 to Day 22 - days 10 to 21 post vaccination
Secondary Outcome New cases of MVD are ascertained through active surveillance and case detection reports through the national MVD surveillance system. Day 11 to Day 22 - days 10 to 21 post vaccination
Secondary Outcome All Cohort B participants will contribute to efficacy analysis assessed between Study Day 10 to Day 22, group receiving cAd3-Marburg on Study Day 1 will be compared to group receiving cAd3-Marburg on Study Day 22. Select Cohort A participants may be described in efficacy analysis as appropriate. Day 11 to Day 22 - days 10 to 21 post vaccination
RECRUITMENT CENTRES
Name of recruitment centre Street address City Postal code Country
Armauer Hansen Research Institute AHRI Jimma Road, ALERT Compound, Addis Ababa, Ethiopia Addis Ababa 1005 Ethiopia
Jinka South Ethiopia Regional State, Ethiopia Jinka 4213 Ethiopia
Hawassa South Ethiopia Regional State, Ethiopia Hawassa 1560 Ethiopia
Sodo South Ethiopia Regional State, Ethiopia Wolaita Sodo 4620 Ethiopia
FUNDING SOURCES
Name of source Street address City Postal code Country
Coalition for Epidemic Preparedness Innovations CEPI 1901 Pennyslyvania Avenue, NW, Suite 1003 Washington DC 20006 United States of America
SPONSORS
Sponsor level Name Street address City Postal code Country Nature of sponsor
Primary Sponsor Ethiopian Ministry of Health 1234 Sudan Street Addis Ababa, Ethiopia Addis Ababa Ethiopia Government Institution
COLLABORATORS
Name Street address City Postal code Country
Sabin Vaccine Institute Inc 2000 Pennsylvania Avenue, NW, Suite Washington DC 20006 United States of America
CONTACT PEOPLE
Role Name Email Phone Street address
Principal Investigator Kassa Haile kassa.haile@ahri.gov.et +251911396555 P.O Box 1005 Armauer Hansen Research Institute
City Postal code Country Position/Affiliation
Addis Ababa Ethiopia Principal Investigator
Role Name Email Phone Street address
Scientific Enquiries Aschalew Worku aschalew.worku@moh.gov.et 251115517011 1234 Sudan Street, Addis Ababa, Ethiopia
City Postal code Country Position/Affiliation
Addis Ababa Ethiopia Sponsor Contact Person for Consultations
Role Name Email Phone Street address
Principal Investigator Tesfaye Gelanew tesfaye.gelanew@ahri.gov.et 251980153960 P.O Box 1005 Armauer Hansen Research Institute
City Postal code Country Position/Affiliation
Addis Ababa Ethiopia Co Principal Investigator
Role Name Email Phone Street address
Public Enquiries Ethiopian Ministry of Health info@moh.gov.et 0251115517011 1234 Sudan Street
City Postal code Country Position/Affiliation
Addis Ababa Ethiopia Sponsor
Role Name Email Phone Street address
Public Enquiries Armauer Hansen Research Institute info@ahri.gov.et 251113483752 Jimma Road, ALERT Compound, Addis Ababa, Ethiopia
City Postal code Country Position/Affiliation
Addis Ababa Ethiopia Site
Role Name Email Phone Street address
Scientific Enquiries Armauer Hansen Research Institute info@ahri.gov.et 251113483752 Jimma Road, ALERT Compound, Addis Ababa, Ethiopia
City Postal code Country Position/Affiliation
Addis Ababa Ethiopia Site
Role Name Email Phone Street address
Scientific Enquiries Ethiopian Ministry of Health info@moh.gov.et 0251115517011 1234 Sudan Street
City Postal code Country Position/Affiliation
Addis Ababa Ethiopia Sponsor
Role Name Email Phone Street address
Scientific Enquiries Kassa Haile kassa.haile@ahri.gov.et +251911396555 P.O Box 1005 Armauer Hansen Research Institute
City Postal code Country Position/Affiliation
Addis Ababa Ethiopia Principal Investigator
Role Name Email Phone Street address
Scientific Enquiries Tesfaye Gelanew tesfaye.gelanew@ahri.gov.et +251980153960 P.O Box 1005 Armauer Hansen Research Institute
City Postal code Country Position/Affiliation
Addis Ababa Ethiopia Co Principal Investigator
REPORTING
Share IPD Description Additional Document Types Sharing Time Frame Key Access Criteria
Yes Individual participant data that underlie the results reported in this article, after deidentification (text, tables, figures, and appendices) Statistical Analysis Plan,Study Protocol Beginning 3 months and ending 5 years following article publication Proposal should be directed to Dr. Aschalew Worku. Email - aschalew.worku@moh.gov.et. To gain access, data requestors will need to sign a data access agreement. Data are available for 5 years at a third party website
URL Results Available Results Summary Result Posting Date First Journal Publication Date
No
Result Upload 1: Result Upload 2: Result Upload 3: Result Upload 4: Result Upload 5:
Result URL Hyperlinks Link To Protocol
Result URL Hyperlinks
Changes to trial information
Section Name Field Name Date Reason Old Value Updated Value
Trial Information Official scientific title 20/05/2026 Protocol Amendment A Two-Cohort Phase 2, Rapid Response, Open-Label, Randomized Study to Assess Safety, Efficacy and Immunogenicity of an Investigational Monovalent Chimpanzee Adenoviral-Vectored Marburg Virus Vaccine in Adults in an Outbreak Setting A Two-Cohort Phase 2, Rapid Response, Open-Label, Randomized Study to Assess Safety, Efficacy and Immunogenicity of an Investigational Monovalent Chimpanzee Adenoviral-Vectored Marburg Virus Vaccine in Adults in an Outbreak Setting
Section Name Field Name Date Reason Old Value Updated Value
Trial Information Trial description 20/05/2026 Protocol Amendment Currently there are no approved vaccines or therapeutics to treat individuals infected with MARV. Previous studies have evaluated the safety and immunogenicity of the cAd3-Marburg vaccine in a small group of healthy adults up to 50 years of age in the United States (US) (NCT04723602). In the first Phase 2 trial, safety was assessed in 125 adults up to 70 years of age at sites within Uganda and Kenya with immunogenicity analyses in progress (NCT05817422). In the second trial, safety was assessed in 1,708 subjects in an outbreak-response trial in Rwanda where samples from 689+ participants were collected and are pending immunogenicity analyses. The third trial being conducted in 200 adults up to 70 years at multiple sites within the United States is fully enrolled with safety and immunogenicity data being collected. Ethiopia has recently declared an outbreak of MARV and, as of November 5th, 2025, there were 5 laboratory confirmed MARV cases, of whom 3 patients died, and 2 are in isolation and treatment. Daily updates on the outbreak are provided by the Ethiopian MoH. The purpose of this study is to describe the safety, efficacy, and immune response of cAd3-Marburg vaccine during the early stages of a Marburg outbreak in Ethiopia in two cohorts. This trial mirrors and takes advantage of lessons-learned from the cAd3-Marburg trial in response to the 2024 Rwanda Marburg outbreak. Primary Objective To describe the safety and tolerability of cAd3-Marburg vaccine Secondary Objectives To determine the immunogenicity of the cAd3-Marburg vaccine at Study Day 29 and Day 91 To estimate vaccine efficacy: To assess the effect of cAd3-Marburg vaccine between Study Day 10 to Day 22 (days 10 to 21 post vaccination) on the rate of virologically confirmed MVD, regardless of severity Currently there are no approved vaccines or therapeutics to treat individuals infected with MARV. Previous studies have evaluated the safety and immunogenicity of the cAd3-Marburg vaccine in a small group of healthy adults up to 50 years of age in the United States (US) (NCT04723602). In the first Phase 2 trial, safety was assessed in 125 adults up to 70 years of age at sites within Uganda and Kenya with immunogenicity analyses in progress (NCT05817422). In the second trial, safety was assessed in 1,708 subjects in an outbreak-response trial in Rwanda where samples from 689+ participants were collected and are pending immunogenicity analyses. The third trial being conducted in 200 adults up to 70 years at multiple sites within the United States is fully enrolled with safety and immunogenicity data being collected. Ethiopia has recently declared an outbreak of MARV and, as of November 5th, 2025, there were 5 laboratory confirmed MARV cases, of whom 3 patients died, and 2 are in isolation and treatment. Daily updates on the outbreak are provided by the Ethiopian MoH. The purpose of this study is to describe the safety, efficacy, and immune response of cAd3-Marburg vaccine during the early stages of a Marburg outbreak in Ethiopia in two cohorts. This trial mirrors and takes advantage of lessons-learned from the cAd3-Marburg trial in response to the 2024 Rwanda Marburg outbreak. Primary Objective To describe the safety and tolerability of cAd3-Marburg vaccine Secondary Objectives To determine the immunogenicity of the cAd3-Marburg vaccine at Study Day 29 and Day 91 To estimate vaccine efficacy: To assess the effect of cAd3-Marburg vaccine between Study Day 11 to Day 22 (days 11 to 21 post vaccination) on the rate of virologically confirmed MVD, regardless of severity
Section Name Field Name Date Reason Old Value Updated Value
Trial Information Actual trial start date 20/05/2026 Actual Trial start Date has been updated 07 Dec 2025
Section Name Field Name Date Reason Old Value Updated Value
Trial Information Recruitment status 20/05/2026 Recruitment status has been updated to completed Not yet recruiting Completed
Section Name Field Name Date Reason Old Value Updated Value
Study Design Intervention assignment 08/12/2025 Suggestion made by administrator. Randomization done to allow for delayed randomization for some participants Single Group Factorial: participants randomly allocated to either no, one, some or all interventions simultaneously
Section Name Field Name Date Reason Old Value Updated Value
Study Design Intervention assignment 08/12/2025 Suggestion made by administrator. Randomization done to allow for delayed randomization for some participants Factorial: participants randomly allocated to either no, one, some or all interventions simultaneously Single Group
Section Name Field Name Date Reason Old Value Updated Value
Study Design Intervention assignment 08/12/2025 As per PACTR representative suggestion Single Group Factorial: participants randomly allocated to either no, one, some or all interventions simultaneously
Section Name Field Name Date Reason Old Value Updated Value
Study Design Intervention assignment 08/12/2025 As per PACTR representative suggestion Factorial: participants randomly allocated to either no, one, some or all interventions simultaneously Parallel: different groups receive different interventions at same time during study
Section Name Field Name Date Reason Old Value Updated Value
Study Design Intervention assignment 08/12/2025 As per PACTR representative suggestion. There is no placebo, the randomization is between D1 vs D22 for vaccination. Request to approve now and we can reassess changes Parallel: different groups receive different interventions at same time during study Single Group
Section Name Field Name Date Reason Old Value Updated Value
Study Design Intervention assignment 08/12/2025 As per PACTR representative suggestion. There is no placebo, the randomization is between D1 vs D22 for vaccination. Request to approve now and we can reassess changes Single Group Factorial: participants randomly allocated to either no, one, some or all interventions simultaneously
Section Name Field Name Date Reason Old Value Updated Value
Eligibility Age group 26/06/2026 PACTR Admin Adolescent: 13 Year(s)-17 Year(s), Adult: 18 Year(s)-44 Year(s), Middle Aged: 45 Year(s)-64 Year(s), Aged: 65 Year(s)-79 Year(s), 80 and over: 80+ Year Adult: 18 Year(s)-44 Year(s), Middle Aged: 45 Year(s)-64 Year(s), Aged: 65 Year(s)-79 Year(s), 80 and over: 80+ Year
Section Name Field Name Date Reason Old Value Updated Value
Intervention Intervention List 08/12/2025 To allow for approval of the study design Control Group, Not applicable, Not applicable, Not applicable, Not applicable, 0, Placebo
Section Name Field Name Date Reason Old Value Updated Value
Outcome OutCome List 20/05/2026 Protocol Amendment Secondary Outcome, New cases of MVD are ascertained through active surveillance and case detection reports through the national MVD surveillance system., Day 10 to Day 22 - days 10 to 21 post vaccination Secondary Outcome, New cases of MVD are ascertained through active surveillance and case detection reports through the national MVD surveillance system., Day 11 to Day 22 - days 10 to 21 post vaccination
Section Name Field Name Date Reason Old Value Updated Value
Outcome OutCome List 20/05/2026 Protocol Amendment Secondary Outcome, All Cohort B participants will contribute to efficacy analysis assessed between Study Day 10 to Day 22, group receiving cAd3-Marburg on Study Day 1 will be compared to group receiving cAd3-Marburg on Study Day 22. Select Cohort A participants may be described in efficacy analysis as appropriate., Day 10 to Day 22 - days 10 to 21 post vaccination Secondary Outcome, All Cohort B participants will contribute to efficacy analysis assessed between Study Day 10 to Day 22, group receiving cAd3-Marburg on Study Day 1 will be compared to group receiving cAd3-Marburg on Study Day 22. Select Cohort A participants may be described in efficacy analysis as appropriate., Day 11 to Day 22 - days 10 to 21 post vaccination
Section Name Field Name Date Reason Old Value Updated Value
Ethics Ethics List 20/05/2026 Protocol Amendment Approval Received TRUE, AHRI ALERT Ethics Review Committee AAERC, Jimma Road, ALERT Compound P.O. Box 1005 Addis Ababa, Ethiopia , Addis Ababa, 00000, Ethiopia, , 21 Nov 2025, 251113483752, admin@ahri.gov.et, 39655_36835_4737.pdf TRUE, AHRI ALERT Ethics Review Committee AAERC, Jimma Road, ALERT Compound P.O. Box 1005 Addis Ababa, Ethiopia , Addis Ababa, 00000, Ethiopia, , 02 Jan 2026, 251113483752, admin@ahri.gov.et, 39655_36835_4737.pdf
Section Name Field Name Date Reason Old Value Updated Value
Ethics Ethics List 20/05/2026 Protocol Amendment Approval Received TRUE, Ethiopian National Research Ethics Review Board, Arada Sub City, Addis Ababa, 00000, Ethiopia, , 06 Jan 2026, +251111553133, info@moe.gov.et, 39655_38367_4737.pdf