Influenza, HumanPhase 1/2NCT06382311
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 study testing Flu Pandemic mRNA_Dose level 1, Flu Pandemic mRNA_Dose level 2 and Flu Pandemic mRNA_ Dose level 3. in people with Influenza, Human, run by GlaxoSmithKline at 21 sites in United States.
Trial 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. Read more about this study
- Who is it for?
- Ages 18 to 85 yearsHealthy volunteers can take part
- Conditions the study is for
- Influenza, Human
- What is being tested?
- Flu Pandemic mRNA_Dose level 1, Flu Pandemic mRNA_Dose level 2 and Flu Pandemic mRNA_ Dose level 3.
- Type of treatment
- Vaccines, Injection or infusion
- Could I receive a placebo?
- Yes, some participants may receive a placebo
- How many people
- 991 participants
- Where
- 21 sitesUnited States
- Study dates
- 18 Apr 2024to 13 Jan 2026
- Phase
- Phase 1/2
- Are there results?
- None posted in the registry
Key requirements
Who can take part, as listed by the sponsor. Only the study team can confirm whether you are eligible, so take this list to your doctor.
- Ages 18 to 85 years
- All sexes
- Healthy volunteers accepted
- Adult, Older adult
Who may be able to join
- 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.
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- 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.
Who cannot join
- Medical conditions
- Where applicable, FDA toxicity grades will be exclusionary.
- 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.
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- 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.
- Chronic administration of immune-modifying drugs (defined as more than 14 consecutive days in total) and/or planned use of long-acting immune-modifying treatments at any time up to the end of the study.
- Up to 3 months prior to the study intervention administration:
- For corticosteroids, this will mean prednisone equivalent 20 mg/day. Inhaled, intra-articular and topical corticosteroids are allowed. If systemic corticosteroids have been administered short term (<14 days) for treatment of an acute illness, participants should not be enrolled into the study until corticosteroid therapy has been discontinued for at least 28 days before study vaccine administration.
- Up to 3 months prior to study intervention administration: long-acting immune-modifying drugs including among others immunotherapy (e.g., TNF-inhibitors), monoclonal antibodies, antitumoral medication.
- Administration of immunoglobulins and/or any blood products or plasma derivatives within 3 months before study intervention administration through end of study.
- Prior/concurrent clinical study experience
- Concurrently participating in another clinical study, at any time during the study period, in which the participant has been or will be exposed to an investigational or a non-investigational intervention (drug/invasive medical device).
- Participated in an A(H5) influenza vaccine study in the past or have a history of A(H5) influenza infection prior to dosing in this study. This includes influenza subtypes A(H5N1), A(H5N8), A(H5N6).
- Other exclusion criteria
- Pregnant or lactating female participant.
- Female planning to become pregnant or planning to discontinue contraceptive precautions within 1 months after completion of the vaccination series.
- Has a history of chronic alcohol consumption and/or drug abuse as deemed by the investigator to render the potential participant unable/unlikely to provide accurate safety reports or comply with study procedures.
- Any study personnel or their immediate dependents, family, or household members.
- Participants with extensive tattoos covering deltoid region on both arms that would preclude the assessment of local reactogenicity.
- Planned move during the study period that will prohibit participating in the study until study end.
- Donation of blood 3 months prior to the study intervention administration and during the study period.
Trial locations and contacts
21 sites in 1 country.
21 sites in 1 country
United States21 sites
GSK Investigational Site
Anniston, Alabama, 36207
GSK Investigational Site
Austin, Texas, 78705
GSK Investigational Site
Chamblee, Georgia, 30043
GSK Investigational Site
Edmond, Oklahoma, 73013
GSK Investigational Site
El Dorado, Kansas, 67042
GSK Investigational Site
Fort Collins, Colorado, 80525
GSK Investigational Site
Fort Myers, Florida, 33912
GSK Investigational Site
Greensboro, North Carolina, 27405
GSK Investigational Site
Kansas City, Missouri, 64114
GSK Investigational Site
Las Vegas, Nevada, 89102
GSK Investigational Site
Lenexa, Kansas, 66219
GSK Investigational Site
Lexington, Kentucky, 40509
GSK Investigational Site
Little Rock, Arkansas, 72204
GSK Investigational Site
Norfolk, Virginia, 23502
GSK Investigational Site
Omaha, Nebraska, 68144
GSK Investigational Site
Philadelphia, Pennsylvania, 19111
GSK Investigational Site
Rochester, New York, 14609
GSK Investigational Site
Seattle, Washington, 98104
GSK Investigational Site
West Palm Beach, Florida, 33409
GSK Investigational Site
Winston-Salem, North Carolina, 27103
GSK Investigational Site
Yukon, Oklahoma, 73099
About this study
Official title: 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
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.
Read the detailed description
Phase 1 (Ph1) of the study aims to evaluate the reactogenicity, safety, and immunogenicity of 5 dose levels of the investigational vaccine, compared with a placebo, in both younger adults (YA) and older adults (OA). Participants will receive two doses, 21 days apart, with safety data collected up to Day 29. The data from this phase will support the safety evaluation of the assessed dose levels and enable further assessment in higher number of participants in Phase 2 Part A.
Phase 2 (Ph2) Part A will assess the immunogenicity, reactogenicity, and safety of the same 5 dose levels evaluated in Phase 1, with the aim of identifying the doses to proceed to Phase 2 Part B.
Phase 2 Part B will descriptively characterize the dose level of the Flu Pandemic mRNA vaccine candidate selected from Phase 2 Part A, comparing it to an influenza vaccine in a 2-dose schedule. It will also assess safety, reactogenicity, and the immune response induced by the influenza vaccine.
- Conditions
- Influenza, Human
- Being tested
- Flu Pandemic mRNA_Dose level 1, Flu Pandemic mRNA_Dose level 2, Flu Pandemic mRNA_ Dose level 3., Flu Pandemic mRNA_ Dose level 4, Flu Pandemic mRNA_Dose level 5
- Keywords
- Influenza A virus, Avian influenza, Flu pandemic, Healthy younger adults, Healthy older adults, Safety, Reactogenicity, Immunogenicity
- Medical subject headings
- Influenza, Human, Influenza in Birds
What participants receive
What participants receive. In a randomised study each person is assigned to one group by chance.
Flu Pandemic mRNA_Dose level 1Biological
2 doses of study intervention are administered to participants intramuscularly.
Flu Pandemic mRNA_Dose level 2Biological
2 doses of study intervention are administered to participants intramuscularly.
Flu Pandemic mRNA_ Dose level 3.Biological
2 doses of study intervention are administered to participants intramuscularly.
Flu Pandemic mRNA_ Dose level 4Biological
2 doses of study intervention are administered to participants intramuscularly.
Flu Pandemic mRNA_Dose level 5Biological
2 doses of study intervention are administered to participants intramuscularly.
Flu Pandemic mRNA_Dose level 6Biological
2 dose of study intervention is administered to participants intramuscularly.
Influenza virus vaccineBiological
2 doses of Influenza virus vaccine are administered to participants intramuscularly.
PlaceboDrug
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.
| Study group | Role | What they receive |
|---|---|---|
| Flu mRNA_Ph1_1_YA | Experimental | YA participants receive 2 doses of Flu Pandemic mRNA_Dose level 1 during Phase 1, at Day 1 and at Day 22. Receives: Biological: Flu Pandemic mRNA_Dose level 1 |
| Flu mRNA_Ph1_2_YA | Experimental | YA participants receive 2 doses of Flu Pandemic mRNA_Dose level 2 during Phase 1, at Day 1 and at Day 22. Receives: Biological: Flu Pandemic mRNA_Dose level 2 |
| Flu mRNA_Ph1_3_YA | Experimental | YA participants receive 2 doses of Flu Pandemic mRNA_Dose level 3 during Phase 1, at Day 1 and at Day 22. Receives: Biological: Flu Pandemic mRNA_ Dose level 3. |
| Flu mRNA_Ph1_4_YA | Experimental | YA participants receive 2 doses of Flu Pandemic mRNA_Dose level 4 during Phase 1, at Day 1 and at Day 22. Receives: Biological: Flu Pandemic mRNA_ Dose level 4 |
| Flu mRNA_Ph1_5_YA | Experimental | YA participants receive 2 doses of Flu Pandemic mRNA_Dose level 5 during Phase 1, at Day 1 and at Day 22. Receives: Biological: Flu Pandemic mRNA_Dose level 5 |
| Placebo_Ph1_YA | Placebo comparator | YA participants receive 2 doses of Placebo during Phase 1, at Day 1 and at Day 22. Receives: Drug: Placebo |
| Flu mRNA_Ph1_1_OA | Experimental | OA participants receive 2 doses of Flu Pandemic mRNA_Dose level 1 during Phase 1, at Day 1 and at Day 22. Receives: Biological: Flu Pandemic mRNA_Dose level 1 |
| Flu mRNA_Ph1_2_OA | Experimental | OA participants receive 2 doses of Flu Pandemic mRNA_Dose level 2 during Phase 1, at Day 1 and at Day 22. Receives: Biological: Flu Pandemic mRNA_Dose level 2 |
| Flu mRNA_Ph1_3_OA | Experimental | OA participants receive 2 doses of Flu Pandemic mRNA_Dose level 3 during Phase 1, at Day 1 and at Day 22. Receives: Biological: Flu Pandemic mRNA_ Dose level 3. |
| Flu mRNA_Ph1_4_OA | Experimental | OA participants receive 2 doses of Flu Pandemic mRNA_Dose level 4 during Phase 1, at Day 1 and at Day 22. Receives: Biological: Flu Pandemic mRNA_ Dose level 4 |
| Flu mRNA_Ph1_5_OA | Experimental | OA participants receive 2 doses of Flu Pandemic mRNA_Dose level 5 during Phase 1, at Day 1 and at Day 22. Receives: Biological: Flu Pandemic mRNA_Dose level 5 |
| Placebo_Ph1_OA | Placebo comparator | OA Adult participants receive 2 doses of Placebo during Phase 1, at Day 1 and at Day 22. Receives: Drug: Placebo |
| Flu mRNA_Ph2_1_YA Part A | Experimental | YA participants receive 2 doses of Flu Pandemic mRNA_Dose level 1 during Phase 2 Part A, at Day 1 and at Day 22. Receives: Biological: Flu Pandemic mRNA_Dose level 1 |
| Flu mRNA_Ph2_2_YA Part A | Experimental | YA participants receive 2 doses of Flu Pandemic mRNA_Dose level 2 during Phase 2 Part A, at Day 1 and at Day 22. Receives: Biological: Flu Pandemic mRNA_Dose level 2 |
| Flu mRNA_Ph2_3_YA Part A | Experimental | YA participants receive 2 doses of Flu Pandemic mRNA_Dose level 3 during Phase 2 Part A, at Day 1 and at Day 22. Receives: Biological: Flu Pandemic mRNA_ Dose level 3. |
| Flu mRNA_Ph2_4_YA Part A | Experimental | YA participants receive 2 doses of Flu Pandemic mRNA_Dose level 4 during Phase 2 Part A, at Day 1 and at Day 22. Receives: Biological: Flu Pandemic mRNA_ Dose level 4 |
| Flu mRNA_Ph2_5_YA Part A | Experimental | YA participants receive 2 doses of Flu Pandemic mRNA_Dose level 5 during Phase 2 Part A, at Day 1 and at Day 22. Receives: Biological: Flu Pandemic mRNA_Dose level 5 |
| Placebo_Ph2_YA Part A | Placebo comparator | YA participants receive 2 doses of Placebo during Phase 2 Part A, at Day 1 and at Day 22. Receives: Drug: Placebo |
| Flu mRNA_Ph2_1_OA Part A | Experimental | OA participants receive 2 doses of Flu Pandemic mRNA_Dose level 1 during Phase 2 Part A, at Day 1 and at Day 22. Receives: Biological: Flu Pandemic mRNA_Dose level 1 |
| Flu mRNA_Ph2_2_OA Part A | Experimental | OA participants receive 2 doses of Flu Pandemic mRNA_Dose level 2 during Phase 2 Part A, at Day 1 and at Day 22. Receives: Biological: Flu Pandemic mRNA_Dose level 2 |
| Flu mRNA_Ph2_3_OA Part A | Experimental | OA participants receive 2 doses of Flu Pandemic mRNA_Dose level 3 during Phase 2 Part A, at Day 1 and at Day 22. Receives: Biological: Flu Pandemic mRNA_ Dose level 3. |
| Flu mRNA_Ph2_4_OA Part A | Experimental | OA participants receive 2 doses of Flu Pandemic mRNA_Dose level 4 during Phase 2 Part A, at Day 1 and at Day 22. Receives: Biological: Flu Pandemic mRNA_ Dose level 4 |
| Flu mRNA_Ph2_5_OA Part A | Experimental | OA participants receive 2 doses of Flu Pandemic mRNA_Dose level 5 during Phase 2 Part A, at Day 1 and at Day 22. Receives: Biological: Flu Pandemic mRNA_Dose level 5 |
| Placebo_Ph2_OA Part A | Placebo comparator | OA participants receive 2 doses of Placebo during Phase 2 Part A, at Day 1 and at Day 22. Receives: Drug: Placebo |
| Flu mRNA_Ph2 Part B | Experimental | Participants receive 2 dose of Flu Pandemic mRNA dose level 6 in Phase 2 Part B, at Day 1 and at Day 22. Receives: Biological: Flu Pandemic mRNA_Dose level 6 |
| Influenza Virus Vaccine_Ph2 Part B | Active comparator | Participants receive 2 doses of influenza virus vaccine administered in Phase 2 Part B, at Day 1 and at Day 22. Receives: Biological: Influenza virus vaccine |
| Placebo_Ph2 Part B | Placebo comparator | Participants receive 2 doses of Placebo during Phase 2 Part B, at Day 1 and at Day 22. Receives: Drug: Placebo |
What is being measured
The primary outcome is the main question the study is designed to answer.
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.
Measured: 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.
Measured: 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.
Measured: 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.
Measured: 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.
Measured: 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.
Measured: 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.
Measured: 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.
Measured: 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.
Measured: 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
Measured: 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
Measured: 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
Measured: 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
Measured: 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]
Measured: 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.
Measured: 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.
Measured: 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.
Measured: 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.
Measured: 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.
Measured: 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.
Measured: 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.
Measured: 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.
Measured: 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.
Measured: 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]
Measured: 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]
Measured: 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]
Measured: 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]
Measured: Baseline (Day 1), Day 29
Percentage of participants with anti-HI titers ≥ 1:40 at Day 43 [Phase 2 Part B]
Measured: 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.
Measured: At Day 43 compared to pre-vaccination (Day 1, pre-dosing)
GMT Ratio of anti-HI antibody titers [Phase 2 Part B]
Measured: At Day 43
Secondary outcomes (22)
Geometric mean titers (GMTs) of HI antibody titers [Phase 1 and Phase 2 Part A]
Measured: 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]
GMI is defined as the geometric mean of the ratios of the post-vaccination to the pre-vaccination titer.
Measured: 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]
GMI is defined as the geometric mean of the within participant ratios of the post-vaccination anti-HI antibody titer to the pre-vaccination anti-HI antibody titer.
Measured: 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]
GMI is defined as the geometric mean of the within participant ratios of the post-vaccination anti-HI antibody titer to the pre-vaccination anti-HI antibody titer.
Measured: 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]
GMI is defined as the geometric mean of the within participant ratios of the post-vaccination anti-HI antibody titer to the pre-vaccination anti-HI antibody titer.
Measured: At Day 203 compared to pre-vaccination (Day 1, pre-dosing)
Percentage of participants with HI antibody Seroconversion rate (SCR) [Phase 1 and Phase 2 Part A]
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.
Measured: At Day 22 compared to pre-vaccination (Day 1, pre-dosing)
Seroconversion rate (SCR) of anti-HI antibody titers [Phase 1 and Phase 2 Part A]
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.
Measured: At Day 29 compared to pre-vaccination (Day 1, pre-dosing)
Seroconversion rate (SCR) of anti-HI antibody titers [Phase 1 and Phase 2 Part A]
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.
Measured: At Day 43 compared to pre-vaccination (Day 1, pre-dosing)
Seroconversion rate (SCR) of anti-HI antibody titers [Phase 1 and Phase 2 Part A]
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.
Measured: At Day 203 compared to pre-vaccination (Day 1, pre-dosing)
Percentage of participants with anti-HI antibody titers >= 1:40 [Phase 1 and Phase 2 Part A]
Measured: At Day 22, Day 29, and Day 203
Percentage of seropositive participants for the HA antibody titers [Phase 1 and Phase 2 Part A]
Seropositivity is defined as titers ≥ lower limit of quantification (LLOQ) at the defined timepoints.
Measured: At Day 1, Day 22, Day 29, Day 43, and Day 203
GMT of Anti-HI antibody titers [Phase 2 Part B]
Measured: At Day 1, Day 22, Day29, Day 43 and Day 203
GMI of anti-HI antibody titers [Phase 2 Part B]
GMI is defined as the geometric mean of the within participant ratios of the post-vaccination anti-HI antibody titer to the pre-vaccination anti-HI antibody titer.
Measured: At Day 22 compared to pre-vaccination (Day 1, pre-dosing)
GMI of anti-HI antibody titers [Phase 2 Part B]
GMI is defined as the geometric mean of the within participant ratios of the post-vaccination anti-HI antibody titer to the pre-vaccination anti-HI antibody titer.
Measured: At Day 29 compared to pre-vaccination (Day 1, pre-dosing)
GMI of anti-HI antibody titers [Phase 2 Part B]
GMI is defined as the geometric mean of the within participant ratios of the post-vaccination anti-HI antibody titer to the pre-vaccination anti-HI antibody titer.
Measured: At Day 43 compared to pre-vaccination (Day 1, pre-dosing)
GMI of anti-HI antibody titers [Phase 2 Part B]
GMI is defined as the geometric mean of the within participant ratios of the post-vaccination anti-HI antibody titer to the pre-vaccination anti-HI antibody titer.
Measured: At Day 203 compared to pre-vaccination (Day 1, pre-dosing)
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.
Measured: At Day 22 compared to pre-vaccination (Day 1, pre-dosing)
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.
Measured: At Day 29 compared to pre-vaccination (Day 1, pre-dosing)
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.
Measured: At Day 43 compared to pre-vaccination (Day 1, pre-dosing)
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.
Measured: At Day 203 compared to pre-vaccination (Day 1, pre-dosing)
Percentage of participants with anti-HI antibody >= 1:40 [Phase 2 Part B]
Measured: At Day 1, Day 22, Day 29, Day 43 and Day 203
Percentage of participants with seropositivity of anti-HI antibody titers [Phase 2 Part B]
Seropositivity is defined as titers ≥ LLOQ at the defined timepoints.
Measured: At Day 1, Day 22, Day 29, Day 43 and Day 203
Timeline
From the start of the study to its completion; the mark is today. Estimated dates are the sponsor’s plan.
- First posted24 Apr 2024
- Study start18 Apr 2024
- Primary completion13 Jan 2026
- Study completion13 Jan 2026
Resources
- Official record on ClinicalTrials.govThe registry entry this page is built from, with its full change history.
- Other trials for Influenza, HumanStudies of the same condition, open and under way.
- More trials run by GlaxoSmithKlineThe sponsor's other registered studies.
- What the trial phases meanHow a treatment moves from first tests in people to approval.
More details
For doctors and researchers: how the study is designed, who runs it, and its registry IDs.
Study design
- Study type
- Interventional
- Phase
- Phase 1/2
- Primary purpose
- Prevention
- Allocation
- Randomised
- Intervention model
- Sequential
- Masking
- Quadruple blind
- Who is masked
- Participant, Care provider, Investigator, Outcomes assessor
- Enrolment
- 991 participants (actual)
Sponsor and investigators
- Lead sponsor
- GlaxoSmithKline
- Sponsor type
- Industry (pharma, biotech, devices)
- Responsible party
- Sponsor
IDs, dates and publications
- ClinicalTrials.gov ID
- NCT06382311
- Sponsor's protocol ID
- 221824
- Status last verified
- Feb 2026
- First submitted
- 16 Apr 2024
- Last updated
- 5 Feb 2026
- Results posted
- No
- Data monitoring committee
- No
- FDA-regulated drug
- Yes
- FDA-regulated device
- No
- Individual data sharing
- Yes: 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/
Study at a glance
From the registry record, last updated by the sponsor on 5 Feb 2026. Recruitment status is as the sponsor reported it: confirm with the study team.
- Official title
- 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
- ClinicalTrials.gov ID
- NCT06382311
- Acronym / sponsor ID
- 221824
- Conditions
- Influenza, Human
- Keywords
- Influenza A virus, Avian influenza, Flu pandemic, Healthy younger adults, Healthy older adults, Safety, Reactogenicity, Immunogenicity
- Phase
- Phase 1/2
- Study type
- Interventional
- Recruitment status
- Completed
- Enrolment
- 991 participants (actual)
- Lead sponsor
- GlaxoSmithKlineIndustry (pharma, biotech, devices)
- Study start
- 18 Apr 2024 (actual)
- Primary completion
- 13 Jan 2026 (actual)
- Study completion
- 13 Jan 2026 (actual)
- First posted
- 24 Apr 2024 (actual)
- Results
- Not posted in the source record
Clinical summary
The research question as the sponsor registered it. This describes what the study plans to test, not what it found.
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.
Detailed description
Phase 1 (Ph1) of the study aims to evaluate the reactogenicity, safety, and immunogenicity of 5 dose levels of the investigational vaccine, compared with a placebo, in both younger adults (YA) and older adults (OA). Participants will receive two doses, 21 days apart, with safety data collected up to Day 29. The data from this phase will support the safety evaluation of the assessed dose levels and enable further assessment in higher number of participants in Phase 2 Part A.
Phase 2 (Ph2) Part A will assess the immunogenicity, reactogenicity, and safety of the same 5 dose levels evaluated in Phase 1, with the aim of identifying the doses to proceed to Phase 2 Part B.
Phase 2 Part B will descriptively characterize the dose level of the Flu Pandemic mRNA vaccine candidate selected from Phase 2 Part A, comparing it to an influenza vaccine in a 2-dose schedule. It will also assess safety, reactogenicity, and the immune response induced by the influenza vaccine.
Study design
- Primary purpose
- Prevention
- Allocation
- Randomised
- Intervention model
- Sequential
- Masking
- Quadruple blind (participant, care provider, investigator, outcomes assessor)
- Number of arms
- 27
| Arm | Type | Receives |
|---|---|---|
| Flu mRNA_Ph1_1_YA | Experimental | Biological: Flu Pandemic mRNA_Dose level 1YA 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 | Experimental | Biological: Flu Pandemic mRNA_Dose level 2YA 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 | Experimental | Biological: Flu Pandemic mRNA_ Dose level 3.YA 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 | Experimental | Biological: Flu Pandemic mRNA_ Dose level 4YA 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 | Experimental | Biological: Flu Pandemic mRNA_Dose level 5YA 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 comparator | Drug: PlaceboYA participants receive 2 doses of Placebo during Phase 1, at Day 1 and at Day 22. |
| Flu mRNA_Ph1_1_OA | Experimental | Biological: Flu Pandemic mRNA_Dose level 1OA 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 | Experimental | Biological: Flu Pandemic mRNA_Dose level 2OA 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 | Experimental | Biological: Flu Pandemic mRNA_ Dose level 3.OA 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 | Experimental | Biological: Flu Pandemic mRNA_ Dose level 4OA 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 | Experimental | Biological: Flu Pandemic mRNA_Dose level 5OA 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 comparator | Drug: PlaceboOA Adult participants receive 2 doses of Placebo during Phase 1, at Day 1 and at Day 22. |
| Flu mRNA_Ph2_1_YA Part A | Experimental | Biological: Flu Pandemic mRNA_Dose level 1YA 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 | Experimental | Biological: Flu Pandemic mRNA_Dose level 2YA 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 | Experimental | Biological: Flu Pandemic mRNA_ Dose level 3.YA 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 | Experimental | Biological: Flu Pandemic mRNA_ Dose level 4YA 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 | Experimental | Biological: Flu Pandemic mRNA_Dose level 5YA 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 comparator | Drug: PlaceboYA 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 | Experimental | Biological: Flu Pandemic mRNA_Dose level 1OA 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 | Experimental | Biological: Flu Pandemic mRNA_Dose level 2OA 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 | Experimental | Biological: Flu Pandemic mRNA_ Dose level 3.OA 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 | Experimental | Biological: Flu Pandemic mRNA_ Dose level 4OA 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 | Experimental | Biological: Flu Pandemic mRNA_Dose level 5OA 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 comparator | Drug: PlaceboOA participants receive 2 doses of Placebo during Phase 2 Part A, at Day 1 and at Day 22. |
| Flu mRNA_Ph2 Part B | Experimental | Biological: Flu Pandemic mRNA_Dose level 6Participants 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 comparator | Biological: Influenza virus vaccineParticipants 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 comparator | Drug: PlaceboParticipants receive 2 doses of Placebo during Phase 2 Part B, at Day 1 and at Day 22. |
Who may qualify
- Ages
- 18 to 85 years
- Sex
- All
- Healthy volunteers
- Accepted
- Age groups
- Adult, Older adult
Key inclusion criteria (10 listed)
- 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.
Key exclusion criteria (32 listed)
- Medical conditions
- Where applicable, FDA toxicity grades will be exclusionary.
- 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.
Eligibility is decided by the study team after screening; this overview does not establish that a patient qualifies. Full inclusion and exclusion criteria.
Interventions
| Intervention | Type | Arms |
|---|---|---|
| Flu Pandemic mRNA_Dose level 12 doses of study intervention are administered to participants intramuscularly. | Biological | Flu mRNA_Ph1_1_OA, Flu mRNA_Ph1_1_YA, Flu mRNA_Ph2_1_OA Part A, Flu mRNA_Ph2_1_YA Part A |
| Flu Pandemic mRNA_Dose level 22 doses of study intervention are administered to participants intramuscularly. | Biological | Flu mRNA_Ph1_2_OA, Flu mRNA_Ph1_2_YA, Flu mRNA_Ph2_2_OA Part A, Flu mRNA_Ph2_2_YA Part A |
| Flu Pandemic mRNA_ Dose level 3.2 doses of study intervention are administered to participants intramuscularly. | Biological | Flu mRNA_Ph1_3_OA, Flu mRNA_Ph1_3_YA, Flu mRNA_Ph2_3_OA Part A, Flu mRNA_Ph2_3_YA Part A |
| Flu Pandemic mRNA_ Dose level 42 doses of study intervention are administered to participants intramuscularly. | Biological | Flu mRNA_Ph1_4_OA, Flu mRNA_Ph1_4_YA, Flu mRNA_Ph2_4_OA Part A, Flu mRNA_Ph2_4_YA Part A |
| Flu Pandemic mRNA_Dose level 52 doses of study intervention are administered to participants intramuscularly. | Biological | Flu mRNA_Ph1_5_OA, Flu mRNA_Ph1_5_YA, Flu mRNA_Ph2_5_OA Part A, Flu mRNA_Ph2_5_YA Part A |
| Flu Pandemic mRNA_Dose level 62 dose of study intervention is administered to participants intramuscularly. | Biological | Flu mRNA_Ph2 Part B |
| Influenza virus vaccine2 doses of Influenza virus vaccine are administered to participants intramuscularly. | Biological | Influenza Virus Vaccine_Ph2 Part B |
| Placebo2 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. | Drug | Placebo_Ph1_OA, Placebo_Ph1_YA, Placebo_Ph2 Part B, Placebo_Ph2_OA Part A, Placebo_Ph2_YA Part A |
Primary outcome
Percentage of participants with solicited administration site events [Phase 1 and Phase 2 Part A]
Time frame: From Day 1 to Day 7
The assessed solicited administration site events are pain at administration site, redness at administration site, swelling at administration site and lymphadenopathy.
Percentage of participants with solicited administration site events [Phase 1 and Phase 2 Part A]
Time frame: From Day 22 to Day 28
The assessed solicited administration site events are pain at administration site, redness at administration site, swelling at administration site and lymphadenopathy.
Percentage of participants with solicited systemic events [Phase 1 and Phase 2 Part A]
Time frame: From Day 1 to Day 7
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.
Percentage of participants with solicited systemic events [Phase 1 and Phase 2 Part A]
Time frame: From Day 22 to Day 28
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.
Percentage of participants with unsolicited adverse events (AEs) [Phase 1 and Phase 2 Part A]
Time frame: From Day 1 to Day 21
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.
Percentage of participants with unsolicited adverse events (AEs) [Phase 1 and Phase 2 Part A]
Time frame: From Day 22 to Day 42
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.
Percentage of participants with medically attended adverse events (MAAEs) [Phase 1 and Phase 2 Part A]
Time frame: From Day 1 to Day 203
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.
Percentage of participants with serious adverse events (SAEs) [Phase 1 and Phase 2 Part A]
Time frame: From Day 1 to Day 203
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.
Percentage of participants with adverse events of special interest (AESIs) [Phase 1 and Phase 2 Part A]
Time frame: From Day 1 to Day 203
Events considered as AESIs are severe hypersensitivity reactions and myocarditis/pericarditis.
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
Time frame: 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
Time frame: 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
Time frame: 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
Time frame: 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]
Time frame: At Day 43
Percentage of participants with solicited administration site events [Phase 2 Part B]
Time frame: From Day 1 to Day 7
The assessed solicited administration site events are pain at administration site, redness at administration site, swelling at administration site and lymphadenopathy.
Percentage of participants with solicited administration site events [Phase 2 Part B]
Time frame: From Day 22 to Day 28
The assessed solicited administration site events are pain at administration site, redness at administration site, swelling at administration site and lymphadenopathy.
Percentage of participants with solicited systemic events [Phase 2 Part B]
Time frame: From Day 1 to Day 7
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.
Percentage of participants with solicited systemic events [Phase 2 Part B]
Time frame: From Day 22 to Day 28
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.
Percentage of participants with unsolicited AEs [Phase 2 Part B]
Time frame: From Day 1 to Day 21
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.
Percentage of participants with unsolicited AEs [Phase 2 Part B]
Time frame: From Day 22 to Day 42
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.
Percentage of participants with MAAEs [Phase 2 Part B]
Time frame: From Day 1 to Day 203
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.
Percentage of participants with SAEs [Phase 2 Part B]
Time frame: From Day 1 to Day 203
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.
Percentage of participants with AESIs [Phase 2 Part B]
Time frame: From Day 1 to Day 203
Events considered as AESIs are severe hypersensitivity reactions, Aminotransferase (AT) elevation and myocarditis/pericarditis.
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]
Time frame: 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]
Time frame: 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]
Time frame: 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]
Time frame: Baseline (Day 1), Day 29
Percentage of participants with anti-HI titers ≥ 1:40 at Day 43 [Phase 2 Part B]
Time frame: At Day 43
Seroconversion rate (SCR) of anti-HI antibody titers [Phase 2 Part B]
Time frame: At Day 43 compared to pre-vaccination (Day 1, pre-dosing)
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.
GMT Ratio of anti-HI antibody titers [Phase 2 Part B]
Time frame: At Day 43
22 secondary outcomes
Geometric mean titers (GMTs) of HI antibody titers [Phase 1 and Phase 2 Part A]
Time frame: 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]
Time frame: 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]
Time frame: 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]
Time frame: 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]
Time frame: At Day 203 compared to pre-vaccination (Day 1, pre-dosing)
Percentage of participants with HI antibody Seroconversion rate (SCR) [Phase 1 and Phase 2 Part A]
Time frame: At Day 22 compared to pre-vaccination (Day 1, pre-dosing)
Seroconversion rate (SCR) of anti-HI antibody titers [Phase 1 and Phase 2 Part A]
Time frame: At Day 29 compared to pre-vaccination (Day 1, pre-dosing)
Seroconversion rate (SCR) of anti-HI antibody titers [Phase 1 and Phase 2 Part A]
Time frame: At Day 43 compared to pre-vaccination (Day 1, pre-dosing)
Seroconversion rate (SCR) of anti-HI antibody titers [Phase 1 and Phase 2 Part A]
Time frame: At Day 203 compared to pre-vaccination (Day 1, pre-dosing)
Percentage of participants with anti-HI antibody titers >= 1:40 [Phase 1 and Phase 2 Part A]
Time frame: At Day 22, Day 29, and Day 203
Percentage of seropositive participants for the HA antibody titers [Phase 1 and Phase 2 Part A]
Time frame: At Day 1, Day 22, Day 29, Day 43, and Day 203
GMT of Anti-HI antibody titers [Phase 2 Part B]
Time frame: At Day 1, Day 22, Day29, Day 43 and Day 203
GMI of anti-HI antibody titers [Phase 2 Part B]
Time frame: At Day 22 compared to pre-vaccination (Day 1, pre-dosing)
GMI of anti-HI antibody titers [Phase 2 Part B]
Time frame: At Day 29 compared to pre-vaccination (Day 1, pre-dosing)
GMI of anti-HI antibody titers [Phase 2 Part B]
Time frame: At Day 43 compared to pre-vaccination (Day 1, pre-dosing)
GMI of anti-HI antibody titers [Phase 2 Part B]
Time frame: At Day 203 compared to pre-vaccination (Day 1, pre-dosing)
Seroconversion rate (SCR) of anti-HI antibody titers [Phase 2 Part B]
Time frame: At Day 22 compared to pre-vaccination (Day 1, pre-dosing)
Seroconversion rate (SCR) of anti-HI antibody titers [Phase 2 Part B]
Time frame: At Day 29 compared to pre-vaccination (Day 1, pre-dosing)
Seroconversion rate (SCR) of anti-HI antibody titers [Phase 2 Part B]
Time frame: At Day 43 compared to pre-vaccination (Day 1, pre-dosing)
Seroconversion rate (SCR) of anti-HI antibody titers [Phase 2 Part B]
Time frame: At Day 203 compared to pre-vaccination (Day 1, pre-dosing)
Percentage of participants with anti-HI antibody >= 1:40 [Phase 2 Part B]
Time frame: At Day 1, Day 22, Day 29, Day 43 and Day 203
Percentage of participants with seropositivity of anti-HI antibody titers [Phase 2 Part B]
Time frame: At Day 1, Day 22, Day 29, Day 43 and Day 203
Results and safety
The study is completed, but results are not available in the source record. That does not mean the treatment did or did not work.
Research links
- Official record on ClinicalTrials.govLast updated by the sponsor 5 Feb 2026.
- Individual participant dataSharing planned: Yes. 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/
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Referral and contact
AzTrials does not enrol participants or take referrals. Contact the study team or a site listed below; they decide who can take part. This study is not recruiting at the moment.
The record lists no contact. Use the official record to reach the sponsor.
21 sites in 1 country: see every site and its status.
Questions about this trial
What is this clinical trial studying?
A Phase 1/2 study testing Flu Pandemic mRNA_Dose level 1, Flu Pandemic mRNA_Dose level 2 and Flu Pandemic mRNA_ Dose level 3. in people with Influenza, Human, run by GlaxoSmithKline at 21 sites in United States.
The full registered description is in the About this study section and the official record.
Who may be eligible to take part?
The sponsor lists 10 inclusion and 32 exclusion criteria. Eligibility is decided by the study team after screening, so read the full criteria and contact a listed site.
Is this clinical trial currently recruiting?
The record says: finished, as of the sponsor's last update on 5 Feb 2026. Status can change between updates, so confirm with the study contact before making plans.
Where is the study taking place?
The record lists 21 sites in United States. Whether a site is taking part right now should be confirmed with that site. See every site.
What are the possible benefits and risks?
They depend on the study and the treatment, and no study can promise a benefit. Some participants in this study may receive a placebo. The study team explains the known risks during informed consent, before anyone joins; the record itself does not list them.
What does this combined phase mean?
Phase 1 studies test a treatment in a small group of people for the first time or in a new way, mainly to check safety and find the right dose.
Phase 2 studies give the treatment to a larger group to see whether it has the intended effect and to keep checking safety.
Not every study follows the same path, and some studies (observational studies, device studies) have no phase.
Are results available for this study?
The study is completed, but results are not available in the source record. That does not mean the treatment did or did not work.
How can a doctor refer a patient or contact the research team?
The record lists no contact. The official record names the sponsor, who can be asked directly. AzTrials does not enrol participants or take referrals.
What does the primary outcome measure?
Percentage of participants with solicited administration site events [Phase 1 and Phase 2 Part A] (time frame: From Day 1 to Day 7). The study lists 30 primary outcomes in all. It is what the study was designed to measure, not a finding.
Where can I read the original study information?
Does a listing mean the treatment is approved or proven to work?
No. A listing means the study is registered. It does not show that the treatment is safe, works, or is approved by a regulator.
How often is this information updated?
AzTrials copies changed records from ClinicalTrials.gov every night and reloads the whole registry every week. The sponsor last updated this record on 5 Feb 2026.