A Study to Find and Confirm the Dose and Assess Safety, Reactogenicity and Immune Response of a Vaccine Against Pandemic H5N1 Influenza Virus in Healthy Younger and Older Adults
A PHASE 1/2, RANDOMIZED, PARTIALLY-BLIND, DOSE-FINDING/DOSE-CONFIRMATION STUDY TO EVALUATE THE SAFETY, REACTOGENICITY AND IMMUNOGENICITY OF THE MRNA-BASED INVESTIGATIONAL PANDEMIC H5 INFLUENZA VACCINE CANDIDATE ADMINISTERED IN HEALTHY YOUNGER AND OLDER ADULTS
1 other identifier
interventional
991
1 country
21
Brief Summary
The aim of this study is to evaluate the safety, reactogenicity and immunogenicity of the Flu Pandemic messenger RNA (mRNA) vaccine (including dose-finding and dose-confirmation) administered in healthy adults 18 to 85 years of age.
Trial Health
Trial Health Score
Automated assessment based on enrollment pace, timeline, and geographic reach
participants targeted
Target at P75+ for phase_1
Started Apr 2024
21 active sites
Health score is calculated from publicly available data and should be used for screening purposes only.
Trial Relationships
Click on a node to explore related trials.
Study Timeline
Key milestones and dates
First Submitted
Initial submission to the registry
April 16, 2024
CompletedStudy Start
First participant enrolled
April 18, 2024
CompletedFirst Posted
Study publicly available on registry
April 24, 2024
CompletedPrimary Completion
Last participant's last visit for primary outcome
January 13, 2026
CompletedStudy Completion
Last participant's last visit for all outcomes
January 13, 2026
CompletedFebruary 5, 2026
February 1, 2026
1.7 years
April 16, 2024
February 3, 2026
Conditions
Keywords
Outcome Measures
Primary Outcomes (30)
Percentage of participants with solicited administration site events [Phase 1 and Phase 2 Part A]
The assessed solicited administration site events are pain at administration site, redness at administration site, swelling at administration site and lymphadenopathy.
From Day 1 to Day 7
Percentage of participants with solicited administration site events [Phase 1 and Phase 2 Part A]
The assessed solicited administration site events are pain at administration site, redness at administration site, swelling at administration site and lymphadenopathy.
From Day 22 to Day 28
Percentage of participants with solicited systemic events [Phase 1 and Phase 2 Part A]
The assessed solicited systemic events are fever, headache, myalgia, arthralgia, fatigue, and chills. Fever is defined as temperature greater than or equal to (\>=)38 degrees Celsius (°C)/ 100.4 Fahrenheit (°F) regardless the location of measurement.
From Day 1 to Day 7
Percentage of participants with solicited systemic events [Phase 1 and Phase 2 Part A]
The assessed solicited systemic events are fever, headache, myalgia, arthralgia, fatigue and chills. Fever is defined as temperature greater than or equal to (\>=)38 degrees Celsius (°C)/ 100.4 Fahrenheit (°F) regardless the location of measurement.
From Day 22 to Day 28
Percentage of participants with unsolicited adverse events (AEs) [Phase 1 and Phase 2 Part A]
An unsolicited AE is an AE that was either not included in the list of solicited events or could be included in the list of solicited events but with an onset outside the specified period of follow-up for solicited events. Unsolicited AEs include both serious and nonserious AEs.
From Day 1 to Day 21
Percentage of participants with unsolicited adverse events (AEs) [Phase 1 and Phase 2 Part A]
An unsolicited AE is an AE that was either not included in the list of solicited events or could be included in the list of solicited events but with an onset outside the specified period of follow-up for solicited events. Unsolicited AEs include both serious and nonserious AEs.
From Day 22 to Day 42
Percentage of participants with medically attended adverse events (MAAEs) [Phase 1 and Phase 2 Part A]
An MAAE is defined as an unsolicited AE for which the participant receives medical attention such as hospitalization, or an emergency room visit, or visit to/by a health care provider.
From Day 1 to Day 203
Percentage of participants with serious adverse events (SAEs) [Phase 1 and Phase 2 Part A]
An SAE is any untoward medical occurrence that results in death, is life-threatening, requires hospitalization or prolongation of existing hospitalization, results in persistent or significant disability/incapacity, is a congenital anomaly/birth defect in the offspring of a study participant, abnormal pregnancy outcomes, is a suspected transmission of any infectious agent via an authorized medicinal product.
From Day 1 to Day 203
Percentage of participants with adverse events of special interest (AESIs) [Phase 1 and Phase 2 Part A]
Events considered as AESIs are severe hypersensitivity reactions and myocarditis/pericarditis.
From Day 1 to Day 203
Phase 1: Percentage of participants with increase in FDA toxicity grading for hematology and clinical chemistry laboratory parameters from baseline to any level of FDA toxicity grading at Day 8
Baseline (Day 1), Day 8
Phase 1: Percentage of participants with increase in FDA toxicity grading in hematology and clinical chemistry laboratory parameters from baseline to any level of FDA toxicity grading at Day 29
Baseline (Day 1), Day 29
Phase 1: Percentage of participants with increase in haematology and clinical chemistry laboratory parameters from normal values at baseline to abnormal values at Day 8
Baseline (Day 1), Day 8
Phase 1: Percentage of participants with increase in hematology and clinical chemistry laboratory parameters from normal values at baseline to abnormal values at Day 29
Baseline (Day 1), Day 29
Percentage of participants with anti- hemagglutinin inhibition (HI) titers ≥ 1:40 at Day 43 [Phase 1 and Phase 2 Part A]
At Day 43
Percentage of participants with solicited administration site events [Phase 2 Part B]
The assessed solicited administration site events are pain at administration site, redness at administration site, swelling at administration site and lymphadenopathy.
From Day 1 to Day 7
Percentage of participants with solicited administration site events [Phase 2 Part B]
The assessed solicited administration site events are pain at administration site, redness at administration site, swelling at administration site and lymphadenopathy.
From Day 22 to Day 28
Percentage of participants with solicited systemic events [Phase 2 Part B]
The assessed solicited systemic events are fever, headache, myalgia, arthralgia, fatigue, and chills. Fever is defined as temperature \>= 38°C/100.4°F regardless the location of measurement. The preferred location for measuring temperature is axillary.
From Day 1 to Day 7
Percentage of participants with solicited systemic events [Phase 2 Part B]
The assessed solicited systemic events are fever, headache, myalgia, arthralgia, fatigue, and chills. Fever is defined as temperature \>= 38°C/100.4°F regardless the location of measurement. The preferred location for measuring temperature is axillary.
From Day 22 to Day 28
Percentage of participants with unsolicited AEs [Phase 2 Part B]
An unsolicited AE is an AE that was either not included in the list of solicited events or could be included in the list of solicited events but with an onset outside the specified period of follow-up for solicited events. Unsolicited AEs include both serious and nonserious AEs.
From Day 1 to Day 21
Percentage of participants with unsolicited AEs [Phase 2 Part B]
An unsolicited AE is an AE that was either not included in the list of solicited events or could be included in the list of solicited events but with an onset outside the specified period of follow-up for solicited events. Unsolicited AEs include both serious and nonserious AEs.
From Day 22 to Day 42
Percentage of participants with MAAEs [Phase 2 Part B]
MAAE is defined as an unsolicited AE for which the participant receives medical attention such as hospitalization, or an emergency room visit, or visit to/by a health care provider.
From Day 1 to Day 203
Percentage of participants with SAEs [Phase 2 Part B]
An SAE is any untoward medical occurrence that results in death, is life-threatening, requires hospitalization or prolongation of existing hospitalization, results in persistent or significant disability/incapacity, is a congenital anomaly/birth defect in the offspring of a study participant, abnormal pregnancy outcomes, is a suspected transmission of any infectious agent via an authorized medicinal product.
From Day 1 to Day 203
Percentage of participants with AESIs [Phase 2 Part B]
Events considered as AESIs are severe hypersensitivity reactions, Aminotransferase (AT) elevation and myocarditis/pericarditis.
From Day 1 to Day 203
Percentage of participants with increase in FDA toxicity grading for clinical chemistry laboratory parameters from baseline to any level of FDA toxicity grading at Day 8 [Phase 2 Part B]
Baseline (Day 1), Day 8
Percentage of participants with increase in FDA toxicity grading for clinical chemistry laboratory parameters from baseline to any level of FDA toxicity grading at Day 29 [Phase 2 Part B]
Baseline (Day 1), Day 29
Percentage of participants with increase in clinical chemistry laboratory parameters from normal values at baseline to abnormal values at Day 8 [Phase 2 Part B]
Baseline (Day 1), Day 8
Percentagev of participants with increase in clinical chemistry laboratory parameters from normal values at baseline to abnormal values at Day 29 [Phase 2 Part B]
Baseline (Day 1), Day 29
Percentage of participants with anti-HI titers ≥ 1:40 at Day 43 [Phase 2 Part B]
At Day 43
Seroconversion rate (SCR) of anti-HI antibody titers [Phase 2 Part B]
HI seroconversion is defined as a post-dose titer ≥1:40 in the serum of participants with pre-dose titer below 1:10 or as a ≥4-fold rise in post dose HI titers with pre- dose titer ≥1:10.
At Day 43 compared to pre-vaccination (Day 1, pre-dosing)
GMT Ratio of anti-HI antibody titers [Phase 2 Part B]
At Day 43
Secondary Outcomes (22)
Geometric mean titers (GMTs) of HI antibody titers [Phase 1 and Phase 2 Part A]
At Day 1, Day 22, Day 29, Day 43, and Day 203
Geometric mean increase (GMI) of HI antibody titers [Phase 1 and Phase 2 Part A]
At Day 22 compared to pre-vaccination (Day 1, pre-dosing)
Geometric mean increase (GMI) of anti-HI antibody titers [Phase 1 and Phase 2 Part A]
At Day 29 compared to pre-vaccination (Day 1, pre-dosing)
Geometric mean increase (GMI) of anti-HI antibody titers [Phase 1 and Phase 2 Part A]
At Day 43 compared to pre-vaccination (Day 1, pre-dosing)
Geometric mean increase (GMI) of anti-HI antibody titers [Phase 1 and Phase 2 Part A]
At Day 203 compared to pre-vaccination (Day 1, pre-dosing)
- +17 more secondary outcomes
Study Arms (27)
Flu mRNA_Ph1_1_YA
EXPERIMENTALYA participants receive 2 doses of Flu Pandemic mRNA\_Dose level 1 during Phase 1, at Day 1 and at Day 22.
Flu mRNA_Ph1_2_YA
EXPERIMENTALYA participants receive 2 doses of Flu Pandemic mRNA\_Dose level 2 during Phase 1, at Day 1 and at Day 22.
Flu mRNA_Ph1_3_YA
EXPERIMENTALYA participants receive 2 doses of Flu Pandemic mRNA\_Dose level 3 during Phase 1, at Day 1 and at Day 22.
Flu mRNA_Ph1_4_YA
EXPERIMENTALYA participants receive 2 doses of Flu Pandemic mRNA\_Dose level 4 during Phase 1, at Day 1 and at Day 22.
Flu mRNA_Ph1_5_YA
EXPERIMENTALYA participants receive 2 doses of Flu Pandemic mRNA\_Dose level 5 during Phase 1, at Day 1 and at Day 22.
Placebo_Ph1_YA
PLACEBO COMPARATORYA participants receive 2 doses of Placebo during Phase 1, at Day 1 and at Day 22.
Flu mRNA_Ph1_1_OA
EXPERIMENTALOA participants receive 2 doses of Flu Pandemic mRNA\_Dose level 1 during Phase 1, at Day 1 and at Day 22.
Flu mRNA_Ph1_2_OA
EXPERIMENTALOA participants receive 2 doses of Flu Pandemic mRNA\_Dose level 2 during Phase 1, at Day 1 and at Day 22.
Flu mRNA_Ph1_3_OA
EXPERIMENTALOA participants receive 2 doses of Flu Pandemic mRNA\_Dose level 3 during Phase 1, at Day 1 and at Day 22.
Flu mRNA_Ph1_4_OA
EXPERIMENTALOA participants receive 2 doses of Flu Pandemic mRNA\_Dose level 4 during Phase 1, at Day 1 and at Day 22.
Flu mRNA_Ph1_5_OA
EXPERIMENTALOA participants receive 2 doses of Flu Pandemic mRNA\_Dose level 5 during Phase 1, at Day 1 and at Day 22.
Placebo_Ph1_OA
PLACEBO COMPARATOROA Adult participants receive 2 doses of Placebo during Phase 1, at Day 1 and at Day 22.
Flu mRNA_Ph2_1_YA Part A
EXPERIMENTALYA participants receive 2 doses of Flu Pandemic mRNA\_Dose level 1 during Phase 2 Part A, at Day 1 and at Day 22.
Flu mRNA_Ph2_2_YA Part A
EXPERIMENTALYA participants receive 2 doses of Flu Pandemic mRNA\_Dose level 2 during Phase 2 Part A, at Day 1 and at Day 22.
Flu mRNA_Ph2_3_YA Part A
EXPERIMENTALYA participants receive 2 doses of Flu Pandemic mRNA\_Dose level 3 during Phase 2 Part A, at Day 1 and at Day 22.
Flu mRNA_Ph2_4_YA Part A
EXPERIMENTALYA participants receive 2 doses of Flu Pandemic mRNA\_Dose level 4 during Phase 2 Part A, at Day 1 and at Day 22.
Flu mRNA_Ph2_5_YA Part A
EXPERIMENTALYA participants receive 2 doses of Flu Pandemic mRNA\_Dose level 5 during Phase 2 Part A, at Day 1 and at Day 22.
Placebo_Ph2_YA Part A
PLACEBO COMPARATORYA participants receive 2 doses of Placebo during Phase 2 Part A, at Day 1 and at Day 22.
Flu mRNA_Ph2_1_OA Part A
EXPERIMENTALOA participants receive 2 doses of Flu Pandemic mRNA\_Dose level 1 during Phase 2 Part A, at Day 1 and at Day 22.
Flu mRNA_Ph2_2_OA Part A
EXPERIMENTALOA participants receive 2 doses of Flu Pandemic mRNA\_Dose level 2 during Phase 2 Part A, at Day 1 and at Day 22.
Flu mRNA_Ph2_3_OA Part A
EXPERIMENTALOA participants receive 2 doses of Flu Pandemic mRNA\_Dose level 3 during Phase 2 Part A, at Day 1 and at Day 22.
Flu mRNA_Ph2_4_OA Part A
EXPERIMENTALOA participants receive 2 doses of Flu Pandemic mRNA\_Dose level 4 during Phase 2 Part A, at Day 1 and at Day 22.
Flu mRNA_Ph2_5_OA Part A
EXPERIMENTALOA participants receive 2 doses of Flu Pandemic mRNA\_Dose level 5 during Phase 2 Part A, at Day 1 and at Day 22.
Placebo_Ph2_OA Part A
PLACEBO COMPARATOROA participants receive 2 doses of Placebo during Phase 2 Part A, at Day 1 and at Day 22.
Flu mRNA_Ph2 Part B
EXPERIMENTALParticipants receive 2 dose of Flu Pandemic mRNA dose level 6 in Phase 2 Part B, at Day 1 and at Day 22.
Influenza Virus Vaccine_Ph2 Part B
ACTIVE COMPARATORParticipants receive 2 doses of influenza virus vaccine administered in Phase 2 Part B, at Day 1 and at Day 22.
Placebo_Ph2 Part B
PLACEBO COMPARATORParticipants receive 2 doses of Placebo during Phase 2 Part B, at Day 1 and at Day 22.
Interventions
2 doses of Placebo are administered intramuscularly to participants in Phase 1 and Phase 2 Part A and 2 dose is administered to participants in Phase 2 Part B.
2 doses of study intervention are administered to participants intramuscularly.
2 doses of study intervention are administered to participants intramuscularly.
2 doses of study intervention are administered to participants intramuscularly.
2 doses of study intervention are administered to participants intramuscularly.
2 doses of study intervention are administered to participants intramuscularly.
2 dose of study intervention is administered to participants intramuscularly.
2 doses of Influenza virus vaccine are administered to participants intramuscularly.
Eligibility Criteria
You may qualify if:
- A male or female between and including 18 and 64 yoa (i.e., 64 years + 364 days; YAs) or between and including 65 and 85 yoa (i.e., 85 years + 364 days; OAs) at the time of the first study intervention administration.
- Participants, who, in the opinion of the investigator, can and will comply with the requirements of the protocol (e.g., completion of the eDiary, return for follow-up visits).
- Body mass index (BMI) more than or equal to (≥)18 kilogram per square meter (kg/m²) and less than or equal to (≤) 35kg/m².
- Written informed consent obtained from the participant prior to performance of any study-specific procedure.
- Healthy participants or medically stable patients as established by medical history, clinical examination, and screening safety laboratory assessments (Where applicable) Participants with chronic medical conditions with or without specific treatment (e.g., chronic metabolic, cardiac, pulmonary, renal, hepatic, neurologic, and hematologic diseases) are allowed to participate in this study, if considered by the investigator as medically stable. A stable medical condition is defined as disease not requiring change in therapy or hospitalization for worsening disease during 3 months before enrollment.
- Females of nonchildbearing potential may be enrolled in the study.
- Females of childbearing potential may be enrolled in the study, if the participant:
- has practiced adequate contraception for 1 month prior to study intervention administration, and
- has a negative pregnancy test at Screening Visit (if applicable) and on the day of each study intervention administration, and
- has agreed to continue adequate contraception for at least 1 month after completion of the last dose of study intervention.
You may not qualify if:
- Medical conditions
- Planned administration of an influenza vaccine before Day 43 time point.
- Current or past malignancy, unless completely resolved without clinically significant sequelae (e.g., no evidence of disease following successful treatment of basal cell carcinoma cases are allowed) for \>5 years.
- Has any medical disease or psychiatric condition that, in the opinion of the investigator, precludes study participation because it would place the participant at an unacceptable risk of injury, would render them unable to meet the requirements of the protocol, or may interfere with successful completion of the study.
- Has a bleeding disorder (e.g., factor deficiency, coagulopathy, or platelet disorder), or prior history of significant bleeding or bruising following intramuscular (IM) injections.
- Any confirmed or suspected immunosuppressive or immunodeficient condition, including HIV infection, based on medical history and physical examination (no laboratory testing required). However, in Phase 2, HIV-infected individuals may be enrolled if they have been stable on antiretroviral therapy for the past 6 consecutive months, i.e., their treatment has not been modified, their CD4 cell count is ≥200/mm³ and their viral load has been undetectable (i.e., HIV-RNA \<50 copies/mL) (based on medical records, no laboratory testing required).
- History of any reaction or hypersensitivity likely to be exacerbated by any component of the study intervention(s) (including polyethylene glycol, aminoglycoside antibiotics and egg products).
- History of uncontrolled neurological disorders or seizures, including Guillain-Barré syndrome and Bell's palsy, with the exception of febrile seizures during childhood.
- Any history of dementia or any medical condition that moderately or severely impairs cognition.
- History of or current suspicion of myocarditis or pericarditis (including following administration, of an mRNA vaccine); or idiopathic cardiomyopathy, or presence of any medical condition that increases the risk myocarditis or pericarditis, including cocaine abuse, cardiomyopathy, endomyocardial fibrosis, hypereosinophilic syndrome, hypersensitivity myocarditis, eosinophilic granulomatosis with polyangiitis and persistent myocardial infection.
- Any other clinical condition that, in the opinion of the investigator, might pose additional risk to the participant due to participation in the study.
- Prior/concomitant therapy
- Use of any investigational or non-registered product (drug, vaccine, or invasive medical device) other than the study intervention(s) during the period beginning 28 days before the dose of study intervention(s) (Day -28 to Day 1), or their planned use during the study period.
- Administration of a vaccine not foreseen by the study protocol in the period starting 28 days before the study intervention administration or planned administration within 21 days after the (last) study intervention administration\*.
- \*If emergency mass vaccination for an unforeseen public health threat (e.g., a pandemic) is recommended and/or organized by public health authorities outside the routine immunization program, the time period described above can be reduced to 7 days if, necessary for that vaccine, provided it is used according to the local governmental recommendations and that the Sponsor is notified accordingly.
- +15 more criteria
Contact the study team to confirm eligibility.
Sponsors & Collaborators
- GlaxoSmithKlinelead
Study Sites (21)
GSK Investigational Site
Anniston, Alabama, 36207, United States
GSK Investigational Site
Little Rock, Arkansas, 72204, United States
GSK Investigational Site
Fort Collins, Colorado, 80525, United States
GSK Investigational Site
Fort Myers, Florida, 33912, United States
GSK Investigational Site
West Palm Beach, Florida, 33409, United States
GSK Investigational Site
Chamblee, Georgia, 30043, United States
GSK Investigational Site
El Dorado, Kansas, 67042, United States
GSK Investigational Site
Lenexa, Kansas, 66219, United States
GSK Investigational Site
Lexington, Kentucky, 40509, United States
GSK Investigational Site
Kansas City, Missouri, 64114, United States
GSK Investigational Site
Omaha, Nebraska, 68144, United States
GSK Investigational Site
Las Vegas, Nevada, 89102, United States
GSK Investigational Site
Rochester, New York, 14609, United States
GSK Investigational Site
Greensboro, North Carolina, 27405, United States
GSK Investigational Site
Winston-Salem, North Carolina, 27103, United States
GSK Investigational Site
Edmond, Oklahoma, 73013, United States
GSK Investigational Site
Yukon, Oklahoma, 73099, United States
GSK Investigational Site
Philadelphia, Pennsylvania, 19111, United States
GSK Investigational Site
Austin, Texas, 78705, United States
GSK Investigational Site
Norfolk, Virginia, 23502, United States
GSK Investigational Site
Seattle, Washington, 98104, United States
MeSH Terms
Conditions
Interventions
Condition Hierarchy (Ancestors)
Intervention Hierarchy (Ancestors)
Study Design
- Study Type
- interventional
- Phase
- phase 1
- Allocation
- RANDOMIZED
- Masking
- QUADRUPLE
- Who Masked
- PARTICIPANT, CARE PROVIDER, INVESTIGATOR, OUTCOMES ASSESSOR
- Masking Details
- Data will be collected in an observer-blind manner in Phase 1 and Phase 2 Part A. Phase 2 Part B: 2 sub-cohorts: Observer-blind and Open label.
- Purpose
- PREVENTION
- Intervention Model
- SEQUENTIAL
- Sponsor Type
- INDUSTRY
- Responsible Party
- SPONSOR
Study Record Dates
First Submitted
April 16, 2024
First Posted
April 24, 2024
Study Start
April 18, 2024
Primary Completion
January 13, 2026
Study Completion
January 13, 2026
Last Updated
February 5, 2026
Record last verified: 2026-02
Data Sharing
- IPD Sharing
- Will share
- Shared Documents
- STUDY PROTOCOL, SAP, ICF, CSR
- Time Frame
- Anonymized IPD will be made available within 6 months of publication of primary, key secondary and safety results for studies in product with approved indication(s) or terminated asset(s) across all indications.
- Access Criteria
- Anonymized IPD is shared with researchers whose proposals are approved by an Independent Review Panel and after a Data Sharing Agreement is in place. Access is provided for an initial period of 12 months but an extension may be granted, when justified, for up to 6 months.
Qualified researchers may request access to anonymized individual patient-level data (IPD) and related study documents of the eligible studies via the Data Sharing Portal. Details on GSK's data sharing criteria can be found at: https://www.gsk.com/en-gb/innovation/trials/data-transparency/