Influenza, HumanPhase 1/2NCT05975840

Safety and Immunogenicity of Different Formulations of Monovalent Influenza A/Astrakhan/3212/2020 Like (H5N8) Virus Vaccine With AS03 Adjuvant System in Medically Stable Adults

A Phase 1/2 study testing FLU Q-PAN H5N8 375_B, FLU Q-PAN H5N8 375_A and FLU Q-PAN H5N8 750_B in people with Influenza, Human, run by GlaxoSmithKline at 20 sites in United States.

Completed

Finished. The study has ended and is not enrolling. Results may be posted on the official record.

Official record

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Trial summary

The purpose of this study is to assess the safety and immunogenicity of different formulations of monovalent Influenza A/Astrakhan/3212/2020-like virus vaccine with AS03 adjuvant system in adults greater than or equal to (>=)18 years of age. Read more about this study

Who is it for?: Ages 18 years and olderHealthy volunteers can take part
Conditions the study is for: Influenza, Human
What is being tested?: FLU Q-PAN H5N8 375_B, FLU Q-PAN H5N8 375_A and FLU Q-PAN H5N8 750_B
Type of treatment: Vaccines, Injection or infusion
Could I receive a placebo?: No, everyone receives an active treatment
How many people: 518 participants
Where: 20 sitesUnited States
Study dates: 3 Aug 2023to 19 Sep 2024
Phase: Phase 1/2
Are there results?: Yes, posted in the registrySummary in the doctors' view

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 years and older
All sexes
Healthy volunteers accepted
Adult, Older adult

Who may be able to join

Medically stable participants as established by medical history and clinical examination before entering into the study.
A male or female >=18 years of age at the time of signing consent form.
Participants, who, in the opinion of the investigator, can and will comply with the requirements of the protocol.
Written or witnessed/thumb printed informed consent obtained from the participant prior to performance of any study specific procedure.
Female participants of childbearing potential or non-childbearing potential may be enrolled in the study if specific criteria are met.

Who cannot join

Current diagnosis or history of autoimmune disorder(s) except hypothyroidism due to Hashimoto's thyroiditis.
History of any reaction or hypersensitivity likely to be exacerbated by any component of the vaccine.
Clinically significant acute or chronic pulmonary, cardiovascular, hepatic, or renal disease that appears uncontrolled or untreated, as determined by history or physical examination.
Any confirmed or suspected immunosuppressive or immunodeficient condition, based on medical history, physical examination, or abnormalities in screening blood tests.
Recurrent history of or uncontrolled neurological disorders or seizures.
History of Guillain-Barré syndrome.

Show all 26Show fewer

Diagnosed with cancer, or treatment for cancer within 3 years.
Persons with a history of cancer who are disease-free without treatment for 3 years or more are eligible.
Persons with a history of histologically confirmed basal cell carcinoma of the skin successfully treated with local excision only, are accepted and are eligible, but other histologic types of skin cancer are exclusionary.
Women who are disease-free 3 years or more after treatment for breast cancer and receiving long-term prophylaxis are eligible.
Documented human immunodeficiency virus-positive participants.
Bedridden participants.
Personal or family history of narcolepsy.
Food and Drug Administration (FDA) toxicity Grade 2, or greater, laboratory tests at Screening.
Any other clinical condition that, in the opinion of the investigator, might pose additional risk to the participant due to participation in the study.
Use of any investigational or non-registered product other than the study vaccine during the period beginning 30 days before the first dose of study vaccine (Day -29 to Day 1), or planned use during the entire study period.
Use of public health emergency vaccines like coronavirus disease 2019 (COVID-19), Monkey pox (mpox) etc. These can be given at any time, but there should a gap of 2 - weeks before a dose of study vaccine can be given.
Use of any licensed vaccines: prior to receipt of the study vaccine and continuing up to 3 weeks after receiving the dose 2 of study vaccine.
Administration of long-acting immune-modifying drugs at any time during the study period.
Administration of immunoglobulins and/or any blood products or plasma derivatives during the period starting 3 months before the first dose of study vaccine or planned administration during the study period.
Chronic administration of immunosuppressants or other immune-modifying drugs during the period starting 3 months prior to the first vaccine dose and through the entire study period. For corticosteroids, this will mean prednisone equivalent >=20 milligrams/day for 14 days or a total of >=280 mg of prednisone equivalent dose in any 14-day period. Inhaled and topical steroids are allowed.
Pregnant or lactating female.
Female planning to become pregnant or planning to discontinue contraceptive precautions within 2 months after completion of the vaccination series.
History of/or current drug/alcohol abuse.
Any study personnel or their immediate dependents, family, or household member.
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 vaccine/product.

Trial locations and contacts

20 sites in 1 country.

City, postcode or hospital

20 sites in 1 country

United States20 sites

GSK Investigational Site
Anderson, South Carolina, 29621
GSK Investigational Site
Anniston, Alabama, 36207
GSK Investigational Site
Austin, Texas, 78745
GSK Investigational Site
Boerne, Texas, 78006
GSK Investigational Site
Chamblee, Georgia, 30341
GSK Investigational Site
Chula Vista, California, 91911
GSK Investigational Site
El Dorado, Kansas, 67042
GSK Investigational Site
Knoxville, Tennessee, 37920
GSK Investigational Site
Lenexa, Kansas, 66219
GSK Investigational Site
Lexington, Kentucky, 40509
GSK Investigational Site
Long Beach, California, 90806
GSK Investigational Site
Meridian, Idaho, 83642
GSK Investigational Site
Metairie, Louisiana, 70006
GSK Investigational Site
Mobile, Alabama, 36608
GSK Investigational Site
Norfolk, Virginia, 23507
GSK Investigational Site
Pembroke Pines, Florida, 33025
GSK Investigational Site
San Antonio, Texas, 78244
GSK Investigational Site
Santa Ana, California, 92705
GSK Investigational Site
Tempe, Arizona, 85281
GSK Investigational Site
Tomball, Texas, 77375

Other trials in United States

About this study

Official title: A Phase I/II Observer-blind, Randomized, Multi-center Trial to Evaluate the Safety and Immunogenicity of Different Formulations of Monovalent Influenza A/Astrakhan/3212/2020 Like (H5N8) Virus Vaccine With AS03 Adjuvant System (Referred to as Q-Pan H5N8), Given as a Two-dose Series to Adults 18 to 64 Years of Age and 65 Years of Age and Older

Conditions: Influenza, Human
Being tested: FLU Q-PAN H5N8 375_B, FLU Q-PAN H5N8 375_A, FLU Q-PAN H5N8 750_B, FLU Q-PAN H5N8 750_A
Keywords: Influenza, Safety, Immunogenicity
Medical subject headings: Influenza, Human

What participants receive

What participants receive. In a randomised study each person is assigned to one group by chance.

FLU Q-PAN H5N8 375_BBiological
Participants received 2 doses of 375_B vaccine formulation by intramuscular injection in the non-dominant arm.
FLU Q-PAN H5N8 375_ABiological
Participants received 2 doses of 375_A vaccine formulation by intramuscular injection in the non-dominant arm.
FLU Q-PAN H5N8 750_BBiological
Participants received 2 doses of 750_B vaccine formulation by intramuscular injection in the non-dominant arm.
FLU Q-PAN H5N8 750_ABiological
Participants received 2 doses of 750_A vaccine formulation by intramuscular injection in the non-dominant arm.

Study groups in NCT05975840
Study group	Role	What they receive
Age group 18-64: FLU Q-PAN H5N8 375_B	Active comparator	Participants received 2 doses of 375_B vaccine formulation, 21 days apart. Receives: Biological: FLU Q-PAN H5N8 375_B
Age group 18-64: FLU Q-PAN H5N8 375_A	Active comparator	Participants received 2 doses of 375_A vaccine formulation, 21 days apart. Receives: Biological: FLU Q-PAN H5N8 375_A
Age group 18-64: FLU Q-PAN H5N8 750_B	Active comparator	Participants received 2 doses of 750_B vaccine formulation, 21 days apart. Receives: Biological: FLU Q-PAN H5N8 750_B
Age group 18-64: FLU Q-PAN H5N8 750_A	Active comparator	Participants received 2 doses of 750_A vaccine formulation, 21 days apart. Receives: Biological: FLU Q-PAN H5N8 750_A
Age group >=65: FLU Q-PAN H5N8 375_B	Active comparator	Participants received 2 doses of 375_B vaccine formulation, 21 days apart. Receives: Biological: FLU Q-PAN H5N8 375_B
Age group >=65: FLU Q-PAN H5N8 375_A	Active comparator	Participants received 2 doses of 375_A vaccine formulation, 21 days apart. Receives: Biological: FLU Q-PAN H5N8 375_A
Age group >=65: FLU Q-PAN H5N8 750_B	Active comparator	Participants received 2 doses of 750_B vaccine formulation, 21 days apart. Receives: Biological: FLU Q-PAN H5N8 750_B
Age group >=65: FLU Q-PAN H5N8 750_A	Active comparator	Participants received 2 doses of 750_A vaccine formulation, 21 days apart. Receives: Biological: FLU Q-PAN H5N8 750_A

What is being measured

The primary outcome is the main question the study is designed to answer.

Hemagglutination-inhibiting (HI) Antibody Titers Against Vaccine-homologous H5N8
Antibody titers were presented as geometric mean titers (GMTs).
Measured: At Day 43
Geometric Mean Fold Rise (GMFR) of Serum HI Antibody Titers Against Vaccine-homologous H5N8
The GMFR is defined as the geometric mean of the within-subject ratios of the post-vaccination reciprocal HI titer to the pre-vaccination reciprocal HI titer for the vaccine virus.
Measured: At Day 43
Number of Seroprotected (SP) Participants for HI Antibody Titers
Seroprotection rate is defined as the number of participants with HI titer value greater than or equal to (>=) 1:40 which is considered as indicating protection.
Measured: At Day 43
Number of Participants Reporting Each Solicited Administration Site Event Following Dose 1
Solicited administration site events included pain, redness and swelling.
Measured: 7 days (Day 1 to Day 7) following dose 1
Number of Participants Reporting Each Solicited Administration Site Event Following Dose 2
Solicited administration site events included pain, redness and swelling.
Measured: 7 days (Day 22 to Day 28) following dose 2
Number of Participants Reporting Each Solicited Systemic Event Following Dose 1
Solicited systemic events included fatigue, fever, headache, muscle ache, joint pain, shivering (chills), sweating, gastrointestinal symptoms (nausea, vomiting, diarrhea, abdominal pain). Fever is defined as temperature >=38 degrees Celsius (°C) for oral route (preferred location for measuring temperature).
Measured: 7 days (Day 1 to Day 7) following dose 1
Number of Participants Reporting Each Solicited Systemic Event Following Dose 2
Solicited systemic events included fatigue, fever, headache, muscle ache, joint pain, shivering (chills), sweating, gastrointestinal symptoms (nausea, vomiting, diarrhea, abdominal pain). Fever is defined as temperature >=38 degrees Celsius (°C) for oral route (preferred location for measuring temperature).
Measured: 7 days (Day 22 to Day 28) following dose 2
Number of Participants With Any Increase in Toxicity Grading in Hematological Laboratory Parameters Following Dose 1
Hemoglobin, white blood cells (WBC) increase, WBC decrease, platelets, neutrophils, lymphocytes and eosinophils were graded by FDA toxicity grading scale in which grades are Grade 1 = mild, Grade 2 = moderate, Grade 3 = severe and Grade 4 = potentially life threatening. Blood samples were collected for safety laboratory tests from the first 50% of participants of each age and dose group, at 7 days following each vaccination (i.e., Visit 2 and Visit 4).
Measured: 7 days (Day 1 to Day 7) following dose 1
Number of Participants With Any Increase in Toxicity Grading in Hematological Laboratory Parameters Following Dose 2
Hemoglobin, WBC increase, WBC decrease, platelets, neutrophils, lymphocytes and eosinophils were graded by FDA toxicity grading scale in which grades are Grade 1 = mild, Grade 2 = moderate, Grade 3 = severe and Grade 4 = potentially life threatening. Blood samples were collected for safety laboratory tests from the first 50% of participants of each age and dose group, at 7 days following each vaccination (i.e., Visit 2 and Visit 4).
Measured: 7 days (Day 22 to Day 28) following dose 2
Number of Participants With Any Increase in Toxicity Grading in Biochemical Laboratory Parameters Following Dose 1
Sodium increase, sodium decrease, potassium increase, potassium decrease, creatinine, alanine aminotransferase (ALT), aspartate aminotransferase (AST), alkaline phosphatase, total bilirubin and blood urea nitrogen (BUN) were graded by FDA toxicity grading scale in which grades are Grade 1 = mild, Grade 2 = moderate, Grade 3 = severe and Grade 4 = potentially life threatening. Blood samples were collected for safety laboratory tests from the first 50% of participants of each age and dose group, at 7 days following each vaccination (i.e., Visit 2 and Visit 4).
Measured: 7 days (Day 1 to Day 7) following dose 1
Number of Participants With Any Increase in Toxicity Grading in Biochemical Laboratory Parameters Following Dose 2
Sodium increase, sodium decrease, potassium increase, potassium decrease, creatinine, ALT, AST, alkaline phosphatase, total bilirubin and BUN were graded by FDA toxicity grading scale in which grades are Grade 1 = mild, Grade 2 = moderate, Grade 3 = severe and Grade 4 = potentially life threatening. Blood samples were collected for safety laboratory tests from the first 50% of participants of each age and dose group, at 7 days following each vaccination (i.e., Visit 2 and Visit 4).
Measured: 7 days (Day 22 to Day 28) following dose 2
Number of Participants Reporting Unsolicited AEs Following Dose 1
An unsolicited adverse event is defined as an adverse event 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.
Measured: 21 days (Day 1 to Day 22) following dose 1
Number of Participants Reporting Unsolicited AEs Following Dose 2
An unsolicited adverse event is defined as an adverse event 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.
Measured: 21 days (Day 22 to Day 43) following dose 2
Number of Participants Reporting Unsolicited Medically Attended Adverse Events (MAEs) Following Dose 1
MAE is defined as an AE that results in an unscheduled visit to a medical professional (e.g., symptoms or illnesses requiring a hospitalization, emergency room visit, or visit to/by a healthcare provider).
Measured: 21 days (Day 1 to Day 22) following dose 1
Number of Participants Reporting Unsolicited MAEs Following Dose 2
Measured: 21 days (Day 22 to Day 43) following dose 2
Number of Participants Reporting Unsolicited MAEs up to 6 Months Post Dose 2 (Administered on Day 22)
Measured: Up to 6 months post dose 2 (administered on Day 22)
Number of Participants Reporting Serious Adverse Events (SAEs) up to Day 43
An SAE is defined as 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, is an abnormal pregnancy outcome (e.g., spontaneous abortion, fetal death, stillbirth, congenital anomalies, ectopic pregnancy), or is a suspected transmission of any infectious agent via an authorized medicinal product.
Measured: From Day 1 to Day 43
Number of Participants Reporting SAEs up to 6 Months Post Dose 2 (Administered on Day 22)
Measured: Day 1 to 6 months post dose 2 (administered on Day 22)
Number of Participants Reporting Potential Immune-mediated Diseases (pIMDs) up to Day 43
pIMDs are defined a subset of AEs of special interest that includes autoimmune diseases and other inflammatory and/or neurologic disorders of interest which may or may not have an autoimmune etiology.
Measured: From Day 1 to Day 43
Number of Participants Reporting pIMDs up to 6 Months Post Dose 2 (Administered on Day 22)
Measured: Day 1 to 6 months post dose 2 (administered on Day 22)

Secondary outcomes (7)

HI Antibody Titers Against Vaccine-homologous H5N8
Antibody titers were presented as geometric mean titers (GMTs).
Measured: Day 1, Day 22, and 6 months post dose 2 (administered on Day 22)
GMFR of Serum HI Antibody Titers Against Vaccine-homologous H5N8
The GMFR is defined as the geometric mean of the within-subject ratios of the post-vaccination reciprocal HI titer to the pre-vaccination reciprocal HI titer for the vaccine virus.
Measured: At Day 22, and 6 months post dose 2 (administered on Day 22)
Number of Seroprotected Participants for HI Antibody Titers
Seroprotection rate is defined as the number of participants with HI titer value >= 1:40 which is considered as indicating protection.
Measured: At Day 1, Day 22, and 6 months post dose 2 (administered on Day 22)
Number of Seroconverted Participants for HI Antibody Titers
HI seroconversion is defined as a post-vaccination titer >=1:40 in the serum of participants with pre-vaccination titer below 1:10 or as a >=4-fold rise in post-vaccination HI titer with pre-vaccination titer >=1:10.
Measured: At Day 22, Day 43 and 6 months post dose 2 (administered on Day 22)
Microneutralization (MN) Antibody Titers for a Subset of Participants
Microneutralization testing was performed on 50% of the participants, randomly selected and equally distributed across the different age groups.
Measured: At Day 1, Day 22, and 6 months post dose 2 (administered on Day 22)
Number of Seropositive Participants for MN Antibody Titers for a Subset of Participants
A seropositive participant is a participant whose antibody titer is greater than or equal to the assay cut-off value of 1:40.
Measured: At Day 1, Day 22, and 6 months post dose 2 (administered on Day 22)
Number of Participants Meeting Vaccine Response (VR) Criteria of MN Antibody Titers for a Subset of Participants
MN VR is defined as titer >=4x LLOQ for participants with pre-vaccination titer below LLOQ or a >=4 -fold increase from pre-vaccination titer for participants with pre-vaccination titer >=LLOQ.
Measured: At Day 22, Day 43, and 6 months post dose 2 (administered on Day 22)

Timeline

From the start of the study to its completion; the mark is today. Estimated dates are the sponsor’s plan.

3 Aug 202319 Sep 2024

First posted4 Aug 2023
Study start3 Aug 2023
Primary completion21 May 2024
Study completion19 Sep 2024

Resources

Official record on ClinicalTrials.govThe registry entry this page is built from, with its full change history.
Posted resultsParticipant flow, outcome measures and adverse events reported by the sponsor.
Publications (1)Papers the sponsor has linked to this study.
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: Parallel groups
Masking: Quadruple blind
Who is masked: Participant, Care provider, Investigator, Outcomes assessor
Enrolment: 518 participants (actual)

IDs, dates and publications

ClinicalTrials.gov ID: NCT05975840
Sponsor's protocol ID: 219833
Status last verified: Aug 2025
First submitted: 27 Jul 2023
Last updated: 19 Aug 2025
Results posted: Yes, on ClinicalTrials.gov
Data monitoring committee: No
FDA-regulated drug: Yes
FDA-regulated device: No
Individual data sharing: Yes: GSK will assess requests from qualified researchers for anonymized individual patient-level data and related study documents. Data sharing is subject to certain criteria, conditions, and exceptions. For further information, refer to https://www.gsk-studyregister.com/About\_GSK\_Patient\_Level\_Data\_Sharing\_Final\_13July2023.pdf.

Publications

Hastie A, Gupta V, Lese P, Moya J, Schoonbroodt S, Beudjekian S, Struyf F. Immunogenicity and safety of AS03-adjuvanted A/Astrakhan/3212/2020 (H5N8)-like influenza vaccine in adults: Phase 1/2, observer-blinded, randomized trial. Hum Vaccin Immunother. 2026 Dec;22(1):2649314. doi: 10.1080/21645515.2026.2649314. Epub 2026 Jun 11.
PubMed 42274331

Want to know more?

The sponsor has not listed a contact. The official record may have more details.

Talk to your doctor first and take this page with you. Only the study team can confirm whether you can join.

Questions to ask the study team

What is the study trying to find out?
What would I need to do, and how often would I visit?
Could I receive a placebo instead of the treatment?
What are the possible risks and benefits for me?
Will it cost me anything? Are travel or time paid for?
Can I keep seeing my own doctor during the study?
What happens when the study ends?

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Study at a glance

From the registry record, last updated by the sponsor on 19 Aug 2025. Recruitment status is as the sponsor reported it: confirm with the study team.

Official title: A Phase I/II Observer-blind, Randomized, Multi-center Trial to Evaluate the Safety and Immunogenicity of Different Formulations of Monovalent Influenza A/Astrakhan/3212/2020 Like (H5N8) Virus Vaccine With AS03 Adjuvant System (Referred to as Q-Pan H5N8), Given as a Two-dose Series to Adults 18 to 64 Years of Age and 65 Years of Age and Older
ClinicalTrials.gov ID: NCT05975840
Acronym / sponsor ID: 219833
Conditions: Influenza, Human
Keywords: Influenza, Safety, Immunogenicity
Phase: Phase 1/2
Study type: Interventional
Recruitment status: Completed
Enrolment: 518 participants (actual)
Lead sponsor: GlaxoSmithKlineIndustry (pharma, biotech, devices)
Study start: 3 Aug 2023 (actual)
Primary completion: 21 May 2024 (actual)
Study completion: 19 Sep 2024 (actual)
First posted: 4 Aug 2023 (actual)
Results: Posted 20 Feb 2025

Clinical summary

The research question as the sponsor registered it. This describes what the study plans to test, not what it found.

Study design

Primary purpose: Prevention
Allocation: Randomised
Intervention model: Parallel groups
Masking: Quadruple blind (participant, care provider, investigator, outcomes assessor)
Number of arms: 8

Arm	Type	Receives
Age group 18-64: FLU Q-PAN H5N8 375_B	Active comparator	Biological: FLU Q-PAN H5N8 375_BParticipants received 2 doses of 375_B vaccine formulation, 21 days apart.
Age group 18-64: FLU Q-PAN H5N8 375_A	Active comparator	Biological: FLU Q-PAN H5N8 375_AParticipants received 2 doses of 375_A vaccine formulation, 21 days apart.
Age group 18-64: FLU Q-PAN H5N8 750_B	Active comparator	Biological: FLU Q-PAN H5N8 750_BParticipants received 2 doses of 750_B vaccine formulation, 21 days apart.
Age group 18-64: FLU Q-PAN H5N8 750_A	Active comparator	Biological: FLU Q-PAN H5N8 750_AParticipants received 2 doses of 750_A vaccine formulation, 21 days apart.
Age group >=65: FLU Q-PAN H5N8 375_B	Active comparator	Biological: FLU Q-PAN H5N8 375_BParticipants received 2 doses of 375_B vaccine formulation, 21 days apart.
Age group >=65: FLU Q-PAN H5N8 375_A	Active comparator	Biological: FLU Q-PAN H5N8 375_AParticipants received 2 doses of 375_A vaccine formulation, 21 days apart.
Age group >=65: FLU Q-PAN H5N8 750_B	Active comparator	Biological: FLU Q-PAN H5N8 750_BParticipants received 2 doses of 750_B vaccine formulation, 21 days apart.
Age group >=65: FLU Q-PAN H5N8 750_A	Active comparator	Biological: FLU Q-PAN H5N8 750_AParticipants received 2 doses of 750_A vaccine formulation, 21 days apart.

Who may qualify

Ages: 18 years and older
Sex: All
Healthy volunteers: Accepted
Age groups: Adult, Older adult

Key inclusion criteria (5 listed)

Medically stable participants as established by medical history and clinical examination before entering into the study.
A male or female >=18 years of age at the time of signing consent form.
Participants, who, in the opinion of the investigator, can and will comply with the requirements of the protocol.
Written or witnessed/thumb printed informed consent obtained from the participant prior to performance of any study specific procedure.
Female participants of childbearing potential or non-childbearing potential may be enrolled in the study if specific criteria are met.

Key exclusion criteria (26 listed)

Current diagnosis or history of autoimmune disorder(s) except hypothyroidism due to Hashimoto's thyroiditis.
History of any reaction or hypersensitivity likely to be exacerbated by any component of the vaccine.
Clinically significant acute or chronic pulmonary, cardiovascular, hepatic, or renal disease that appears uncontrolled or untreated, as determined by history or physical examination.
Any confirmed or suspected immunosuppressive or immunodeficient condition, based on medical history, physical examination, or abnormalities in screening blood tests.
Recurrent history of or uncontrolled neurological disorders or seizures.

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 Q-PAN H5N8 375_BParticipants received 2 doses of 375_B vaccine formulation by intramuscular injection in the non-dominant arm.	Biological	Age group 18-64: FLU Q-PAN H5N8 375_B, Age group >=65: FLU Q-PAN H5N8 375_B
FLU Q-PAN H5N8 375_AParticipants received 2 doses of 375_A vaccine formulation by intramuscular injection in the non-dominant arm.	Biological	Age group 18-64: FLU Q-PAN H5N8 375_A, Age group >=65: FLU Q-PAN H5N8 375_A
FLU Q-PAN H5N8 750_BParticipants received 2 doses of 750_B vaccine formulation by intramuscular injection in the non-dominant arm.	Biological	Age group 18-64: FLU Q-PAN H5N8 750_B, Age group >=65: FLU Q-PAN H5N8 750_B
FLU Q-PAN H5N8 750_AParticipants received 2 doses of 750_A vaccine formulation by intramuscular injection in the non-dominant arm.	Biological	Age group 18-64: FLU Q-PAN H5N8 750_A, Age group >=65: FLU Q-PAN H5N8 750_A

Primary outcome

Hemagglutination-inhibiting (HI) Antibody Titers Against Vaccine-homologous H5N8
Time frame: At Day 43
Antibody titers were presented as geometric mean titers (GMTs).
Geometric Mean Fold Rise (GMFR) of Serum HI Antibody Titers Against Vaccine-homologous H5N8
Time frame: At Day 43
The GMFR is defined as the geometric mean of the within-subject ratios of the post-vaccination reciprocal HI titer to the pre-vaccination reciprocal HI titer for the vaccine virus.
Number of Seroprotected (SP) Participants for HI Antibody Titers
Time frame: At Day 43
Seroprotection rate is defined as the number of participants with HI titer value greater than or equal to (>=) 1:40 which is considered as indicating protection.
Number of Participants Reporting Each Solicited Administration Site Event Following Dose 1
Time frame: 7 days (Day 1 to Day 7) following dose 1
Solicited administration site events included pain, redness and swelling.
Number of Participants Reporting Each Solicited Administration Site Event Following Dose 2
Time frame: 7 days (Day 22 to Day 28) following dose 2
Solicited administration site events included pain, redness and swelling.
Number of Participants Reporting Each Solicited Systemic Event Following Dose 1
Time frame: 7 days (Day 1 to Day 7) following dose 1
Solicited systemic events included fatigue, fever, headache, muscle ache, joint pain, shivering (chills), sweating, gastrointestinal symptoms (nausea, vomiting, diarrhea, abdominal pain). Fever is defined as temperature >=38 degrees Celsius (°C) for oral route (preferred location for measuring temperature).
Number of Participants Reporting Each Solicited Systemic Event Following Dose 2
Time frame: 7 days (Day 22 to Day 28) following dose 2
Solicited systemic events included fatigue, fever, headache, muscle ache, joint pain, shivering (chills), sweating, gastrointestinal symptoms (nausea, vomiting, diarrhea, abdominal pain). Fever is defined as temperature >=38 degrees Celsius (°C) for oral route (preferred location for measuring temperature).
Number of Participants With Any Increase in Toxicity Grading in Hematological Laboratory Parameters Following Dose 1
Time frame: 7 days (Day 1 to Day 7) following dose 1
Hemoglobin, white blood cells (WBC) increase, WBC decrease, platelets, neutrophils, lymphocytes and eosinophils were graded by FDA toxicity grading scale in which grades are Grade 1 = mild, Grade 2 = moderate, Grade 3 = severe and Grade 4 = potentially life threatening. Blood samples were collected for safety laboratory tests from the first 50% of participants of each age and dose group, at 7 days following each vaccination (i.e., Visit 2 and Visit 4).
Number of Participants With Any Increase in Toxicity Grading in Hematological Laboratory Parameters Following Dose 2
Time frame: 7 days (Day 22 to Day 28) following dose 2
Hemoglobin, WBC increase, WBC decrease, platelets, neutrophils, lymphocytes and eosinophils were graded by FDA toxicity grading scale in which grades are Grade 1 = mild, Grade 2 = moderate, Grade 3 = severe and Grade 4 = potentially life threatening. Blood samples were collected for safety laboratory tests from the first 50% of participants of each age and dose group, at 7 days following each vaccination (i.e., Visit 2 and Visit 4).
Number of Participants With Any Increase in Toxicity Grading in Biochemical Laboratory Parameters Following Dose 1
Time frame: 7 days (Day 1 to Day 7) following dose 1
Sodium increase, sodium decrease, potassium increase, potassium decrease, creatinine, alanine aminotransferase (ALT), aspartate aminotransferase (AST), alkaline phosphatase, total bilirubin and blood urea nitrogen (BUN) were graded by FDA toxicity grading scale in which grades are Grade 1 = mild, Grade 2 = moderate, Grade 3 = severe and Grade 4 = potentially life threatening. Blood samples were collected for safety laboratory tests from the first 50% of participants of each age and dose group, at 7 days following each vaccination (i.e., Visit 2 and Visit 4).
Number of Participants With Any Increase in Toxicity Grading in Biochemical Laboratory Parameters Following Dose 2
Time frame: 7 days (Day 22 to Day 28) following dose 2
Sodium increase, sodium decrease, potassium increase, potassium decrease, creatinine, ALT, AST, alkaline phosphatase, total bilirubin and BUN were graded by FDA toxicity grading scale in which grades are Grade 1 = mild, Grade 2 = moderate, Grade 3 = severe and Grade 4 = potentially life threatening. Blood samples were collected for safety laboratory tests from the first 50% of participants of each age and dose group, at 7 days following each vaccination (i.e., Visit 2 and Visit 4).
Number of Participants Reporting Unsolicited AEs Following Dose 1
Time frame: 21 days (Day 1 to Day 22) following dose 1
An unsolicited adverse event is defined as an adverse event 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.
Number of Participants Reporting Unsolicited AEs Following Dose 2
Time frame: 21 days (Day 22 to Day 43) following dose 2
An unsolicited adverse event is defined as an adverse event 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.
Number of Participants Reporting Unsolicited Medically Attended Adverse Events (MAEs) Following Dose 1
Time frame: 21 days (Day 1 to Day 22) following dose 1
MAE is defined as an AE that results in an unscheduled visit to a medical professional (e.g., symptoms or illnesses requiring a hospitalization, emergency room visit, or visit to/by a healthcare provider).
Number of Participants Reporting Unsolicited MAEs Following Dose 2
Time frame: 21 days (Day 22 to Day 43) following dose 2
Number of Participants Reporting Unsolicited MAEs up to 6 Months Post Dose 2 (Administered on Day 22)
Time frame: Up to 6 months post dose 2 (administered on Day 22)
Number of Participants Reporting Serious Adverse Events (SAEs) up to Day 43
Time frame: From Day 1 to Day 43
An SAE is defined as 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, is an abnormal pregnancy outcome (e.g., spontaneous abortion, fetal death, stillbirth, congenital anomalies, ectopic pregnancy), or is a suspected transmission of any infectious agent via an authorized medicinal product.
Number of Participants Reporting SAEs up to 6 Months Post Dose 2 (Administered on Day 22)
Time frame: Day 1 to 6 months post dose 2 (administered on Day 22)
Number of Participants Reporting Potential Immune-mediated Diseases (pIMDs) up to Day 43
Time frame: From Day 1 to Day 43
pIMDs are defined a subset of AEs of special interest that includes autoimmune diseases and other inflammatory and/or neurologic disorders of interest which may or may not have an autoimmune etiology.
Number of Participants Reporting pIMDs up to 6 Months Post Dose 2 (Administered on Day 22)
Time frame: Day 1 to 6 months post dose 2 (administered on Day 22)

7 secondary outcomes

HI Antibody Titers Against Vaccine-homologous H5N8
Time frame: Day 1, Day 22, and 6 months post dose 2 (administered on Day 22)
GMFR of Serum HI Antibody Titers Against Vaccine-homologous H5N8
Time frame: At Day 22, and 6 months post dose 2 (administered on Day 22)
Number of Seroprotected Participants for HI Antibody Titers
Time frame: At Day 1, Day 22, and 6 months post dose 2 (administered on Day 22)
Number of Seroconverted Participants for HI Antibody Titers
Time frame: At Day 22, Day 43 and 6 months post dose 2 (administered on Day 22)
Microneutralization (MN) Antibody Titers for a Subset of Participants
Time frame: At Day 1, Day 22, and 6 months post dose 2 (administered on Day 22)
Number of Seropositive Participants for MN Antibody Titers for a Subset of Participants
Time frame: At Day 1, Day 22, and 6 months post dose 2 (administered on Day 22)
Number of Participants Meeting Vaccine Response (VR) Criteria of MN Antibody Titers for a Subset of Participants
Time frame: At Day 22, Day 43, and 6 months post dose 2 (administered on Day 22)

Results and safety

Results posted to the registry on 20 Feb 2025, as reported by the sponsor. Figures are copied from the record, not re-analysed. Full results on ClinicalTrials.gov.

Participant flow

Group	Started	Completed
Age Group 18-64: FLU Q-PAN H5N8 375_B	66	61
Age Group 18-64: FLU Q-PAN H5N8 375_A	65	52
Age Group 18-64: FLU Q-PAN H5N8 750_B	64	59
Age Group 18-64: FLU Q-PAN H5N8 750_A	63	59
Age Group >=65: FLU Q-PAN H5N8 375_B	66	61
Age Group >=65: FLU Q-PAN H5N8 375_A	64	61
Age Group >=65: FLU Q-PAN H5N8 750_B	66	62
Age Group >=65: FLU Q-PAN H5N8 750_A	64	58

Primary outcome: Hemagglutination-inhibiting (HI) Antibody Titers Against Vaccine-homologous H5N8

Time frame: At Day 43. Geometric mean (95% Confidence Interval). Unit: Titer

Measure	Age Group 18-64: FLU Q-PAN H5N8 375_B n = 56	Age Group 18-64: FLU Q-PAN H5N8 375_A n = 46	Age Group 18-64: FLU Q-PAN H5N8 750_B n = 47	Age Group 18-64: FLU Q-PAN H5N8 750_A n = 49	Age Group >=65: FLU Q-PAN H5N8 375_B n = 47	Age Group >=65: FLU Q-PAN H5N8 375_A n = 40	Age Group >=65: FLU Q-PAN H5N8 750_B n = 43	Age Group >=65: FLU Q-PAN H5N8 750_A n = 44
Value	117.5 (97.0 to 141.8)	175.2 (142.2 to 216.0)	121.8 (99.2 to 150.1)	176.6 (144.2 to 216.2)	80.6 (64.3 to 101.1)	110.2 (85.3 to 139.7)	84.0 (66.6 to 107.0)	129.3 (102.7 to 164.1)

Population analysed: Analysis was performed on the Per-protocol set (PPS) which included all eligible participants who received the 2 doses of study intervention as per protocol, had Day 1 and Day 43 post dose anti-HI immunogenicity results as per blood draw interval at Day 43. Only those participants with data available at the specified timepoint have been analyzed.

Primary outcome: Geometric Mean Fold Rise (GMFR) of Serum HI Antibody Titers Against Vaccine-homologous H5N8

Time frame: At Day 43. Geometric mean (95% Confidence Interval). Unit: Ratio

Measure	Age Group 18-64: FLU Q-PAN H5N8 375_B n = 56	Age Group 18-64: FLU Q-PAN H5N8 375_A n = 46	Age Group 18-64: FLU Q-PAN H5N8 750_B n = 47	Age Group 18-64: FLU Q-PAN H5N8 750_A n = 49	Age Group >=65: FLU Q-PAN H5N8 375_B n = 47	Age Group >=65: FLU Q-PAN H5N8 375_A n = 40	Age Group >=65: FLU Q-PAN H5N8 750_B n = 43	Age Group >=65: FLU Q-PAN H5N8 750_A n = 44
Value	21.7 (18.3 to 26.7)	33.0 (26.8 to 40.7)	23.7 (18.7 to 28.3)	33.1 (27.2 to 40.7)	11.7 (9.3 to 14.6)	14.3 (12.3 to 20.2)	12.8 (9.6 to 15.4)	19.5 (14.8 to 23.7)

Population analysed: PPS population. Only those participants with data available at the specified timepoint have been analyzed.

Primary outcome: Number of Seroprotected (SP) Participants for HI Antibody Titers

Time frame: At Day 43. Count of participants. Unit: Participants

Measure	Age Group 18-64: FLU Q-PAN H5N8 375_B n = 56	Age Group 18-64: FLU Q-PAN H5N8 375_A n = 46	Age Group 18-64: FLU Q-PAN H5N8 750_B n = 47	Age Group 18-64: FLU Q-PAN H5N8 750_A n = 49	Age Group >=65: FLU Q-PAN H5N8 375_B n = 47	Age Group >=65: FLU Q-PAN H5N8 375_A n = 40	Age Group >=65: FLU Q-PAN H5N8 750_B n = 43	Age Group >=65: FLU Q-PAN H5N8 750_A n = 44
Value	56	45	46	49	43	37	41	41

Population analysed: PPS population. Only those participants with data available at the specified timepoint have been analyzed.

Primary outcome: Number of Participants Reporting Each Solicited Administration Site Event Following Dose 1

Time frame: 7 days (Day 1 to Day 7) following dose 1. Count of participants. Unit: Participants

Measure	Age Group 18-64: FLU Q-PAN H5N8 375_B n = 65	Age Group 18-64: FLU Q-PAN H5N8 375_A n = 59	Age Group 18-64: FLU Q-PAN H5N8 750_B n = 62	Age Group 18-64: FLU Q-PAN H5N8 750_A n = 63	Age Group >=65: FLU Q-PAN H5N8 375_B n = 64	Age Group >=65: FLU Q-PAN H5N8 375_A n = 63	Age Group >=65: FLU Q-PAN H5N8 750_B n = 64	Age Group >=65: FLU Q-PAN H5N8 750_A n = 64
Pain	39	34	27	38	23	22	14	29
Redness	3	0	2	2	0	1	0	4
Swelling	2	0	2	2	2	1	0	5

Population analysed: The analysis was performed on the Diary Set for dose 1 (DS1) which included participants who received a study intervention and provided information on at least 1 solicited adverse event (AE) on at least 1 day.

7 secondary outcomes are reported in the full results.

Adverse events

Time frame: SAEs, MAEs and pIMDs were reported from Day 1 to 6 months post-dose 2 (dose 2 administered on Day 22). Solicited AEs were reported from Day 1 to Day 7 and Day 22 to Day 28 (7 days after each dose). Unsolicited AEs were reported from Day 1 to Day 43.. Other adverse events reported at 0% frequency or more

Group	Serious adverse events	Other adverse events	Deaths
Age Group 18-64: FLU Q-PAN H5N8 375_B	1 of 66 (1.5%)	50 of 66 (75.8%)	0 of 66
Age Group 18-64: FLU Q-PAN H5N8 375_A	1 of 65 (1.5%)	40 of 65 (61.5%)	1 of 65
Age Group 18-64: FLU Q-PAN H5N8 750_B	0 of 64 (0%)	40 of 64 (62.5%)	0 of 64
Age Group 18-64: FLU Q-PAN H5N8 750_A	2 of 63 (3.2%)	50 of 63 (79.4%)	0 of 63
Age Group >=65: FLU Q-PAN H5N8 375_B	2 of 66 (3%)	39 of 66 (59.1%)	0 of 66
Age Group >=65: FLU Q-PAN H5N8 375_A	2 of 64 (3.1%)	44 of 64 (68.8%)	0 of 64
Age Group >=65: FLU Q-PAN H5N8 750_B	2 of 66 (3%)	34 of 66 (51.5%)	0 of 66
Age Group >=65: FLU Q-PAN H5N8 750_A	2 of 64 (3.1%)	41 of 64 (64.1%)	1 of 64

Loading the posted results from ClinicalTrials.gov…

Research links

Official record on ClinicalTrials.govLast updated by the sponsor 19 Aug 2025.
Posted resultsParticipant flow, baseline, all outcome measures and adverse events.
Derived from this study: PubMed 42274331Hastie A, Gupta V, Lese P, Moya J, Schoonbroodt S, Beudjekian S, Struyf F. Immunogenicity and safety of AS03-adjuvanted A/Astrakhan/3212/2020 (H5N8)-like influenza vaccine in adults: Phase 1/2, observer-blinded, randomized trial. Hum Vaccin Immunother. 2026 Dec;22(1):2649314. doi: 10.1080/21645515.2026.2649314. Epub 2026 Jun 11.
Individual participant dataSharing planned: Yes. GSK will assess requests from qualified researchers for anonymized individual patient-level data and related study documents. Data sharing is subject to certain criteria, conditions, and exceptions. For further information, refer to https://www.gsk-studyregister.com/About_GSK_Patient_Level_Data_Sharing_Final_13July2023.pdf.

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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.

20 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 Q-PAN H5N8 375_B, FLU Q-PAN H5N8 375_A and FLU Q-PAN H5N8 750_B in people with Influenza, Human, run by GlaxoSmithKline at 20 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 5 inclusion and 26 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 19 Aug 2025. Status can change between updates, so confirm with the study contact before making plans.

Where is the study taking place?

The record lists 20 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. 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?

Yes. Results are posted in the registry (first posted 20 Feb 2025). A summary is in the For doctors view, and the full results are on ClinicalTrials.gov.

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?

Hemagglutination-inhibiting (HI) Antibody Titers Against Vaccine-homologous H5N8 (time frame: At Day 43). The study lists 20 primary outcomes in all. It is what the study was designed to measure, not a finding.

Where can I read the original study information?

On the ClinicalTrials.gov record for NCT05975840, which also lists 1 linked publication.

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 19 Aug 2025.