A Study on the Safety and Immune Response of Investigational mRNA Seasonal Flu/COVID-19 Combination Vaccine in Adults

A Phase 1, Observer-Blind, Randomized, Controlled Study to Evaluate the Safety and Immunogenicity of an Investigational mRNA Seasonal Flu/COVID-19 Combination Vaccine in Adults

This early-stage study will look at a new mRNA vaccine that combines defenses against both seasonal flu and COVID-19 in terms of its safety and how it builds protection. Healthy adults aged 65 to 85 will receive different doses of this new vaccine, a standard flu vaccine, or COVID-19 vaccine. The study will assess any side effects or health issues, and additional blood samples will be collected at specific times to evaluate how well participants bodies build protection against the flu and COVID-19.

Study Overview

• Status: Recruiting
• Conditions: Influenza, Human+COVID-19
• Intervention / Treatment: Biological: Investigational mRNA Seasonal Flu/COVID-19 Combination (Flu/COVm) Vaccine; Biological: Licensed Seasonal Influenza Vaccine; Biological: Licensed COVID-19 Vaccine

• Study Type: Interventional
• Enrollment (Estimated): 225
• Phase: Phase 1

Contacts and Locations

• Study Contact: Name: US GSK Clinical Trials Call Center; Phone Number: 877-379-3718; Email: GSKClinicalSupportHD@gsk.com
• Study Contact Backup: Name: EU GSK Clinical Trials Call Center; Phone Number: +44 (0) 20 89904466; Email: GSKClinicalSupportHD@gsk.com

Study Locations

• United States
  • California
    • San Diego, California, United States, 92123
      • Recruiting
      • GSK Investigational Site
      • Principal Investigator: Donald Brandon
      • Contact: US GSK Clinical Trials Call Center; Phone Number: 877-379-3718; Email: GSKClinicalSupportHD@gsk.com
      • Contact: EU GSK Clinical Trials Call Centre; Phone Number: +44 (0) 20 8990 4466; Email: GSKClinicalSupportHD@gsk.com
  • Florida
    • Miami, Florida, United States, 33186
      • Recruiting
      • GSK Investigational Site
      • Contact: US GSK Clinical Trials Call Center; Phone Number: 877-379-3718; Email: GSKClinicalSupportHD@gsk.com
      • Contact: EU GSK Clinical Trials Call Centre; Phone Number: +44 (0) 20 8990 4466; Email: GSKClinicalSupportHD@gsk.com
      • Principal Investigator: Rafael A Ubeda

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: Older Adult
• Accepts Healthy Volunteers: No

Description

Inclusion Criteria:

1. Participants, who, in the opinion of the investigator, can and will comply with the requirements of the protocol independently or with the assistance of the caregiver.
2. Informed consent obtained from the participant prior to performance of any study-specific procedure.
3. A male or female 65 to 85 years of age (YoA) (inclusive) at the time of screening.
4. Healthy participants or medically stable patients as established by medical history and clinical examination.
5. Other protocol-defined inclusion criteria may apply.

Exclusion Criteria:

1. Any clinically significant laboratory abnormality.
2. History of symptomatic influenza/ SARS-CoV-2 infection confirmed by local health authority-approved testing methods within 180 days (for influenza) or 90 days (SARS-CoV-2 infection) prior to study intervention administration.
3. History of Guillain-Barré syndrome (GBS) within 6 weeks of receiving any vaccine.
4. 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.
5. Any confirmed or suspected immunosuppressive or immunodeficient condition, based on medical history and physical examination (no laboratory testing required).
6. 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 of myocarditis or pericarditis, including cocaine abuse, cardiomyopathy, endomyocardial fibrosis, hypereosinophilic syndrome, hypersensitivity myocarditis, eosinophilic granulomatosis with polyangiitis and persistent myocardial infection.
7. History of any reaction or hypersensitivity likely to be exacerbated by any component of the study intervention(s).
8. Acute or unstable chronic conditions, clinically significant pulmonary, cardiovascular, or renal functional abnormality, as determined by physical examination and/or laboratory screening tests.
9. History of hypersensitivity or allergic reaction to any previous influenza or COVID-19 vaccine.
10. History of hypersensitivity or allergic reaction to any previous mRNA vaccine.
11. Administration of any influenza vaccine within 181 days before the study intervention administration (Day -180 to Day 1) or planned administration within 28 days (Day 29) after the study intervention administration.
12. Administration of a SARS-CoV-2 antigen-containing vaccine in the period starting 91 days before the study intervention administration (Day -90 to Day 1) or planned administration within 28 days (Day 29) after the study intervention administration.
13. Administration of any mRNA-based vaccine in the period starting 29 days before the study intervention administration (Day -28 to Day 1) or planned administration within 28 days (Day 29) after the study intervention administration.
14. Administration of any other vaccine not foreseen by the study protocol in the period starting 29 days (Day -28 to Day 1) before the study intervention administration or planned administration within 28 days (Day 29) after the study intervention administration.
15. Other protocol-defined exclusion criteria may apply.

Study Plan

How is the study designed?

Design Details

• Primary Purpose: Prevention
• Allocation: Randomized
• Interventional Model: Sequential Assignment
• Masking: Triple

Number of Arms

5

Arms and Interventions

Participant Group / Arm	Intervention / Treatment
Experimental: FLU/COVm_Dose Level 1; Participants receive a single intramuscular administration of the investigational mRNA Seasonal Flu/COVID-19 combination vaccine at dose level 1 (Lowest dose).	Biological: Investigational mRNA Seasonal Flu/COVID-19 Combination (Flu/COVm) Vaccine; Flu/COVm Vaccine with multiple dose levels (Dose Level 1, Dose Level 2, and Dose Level 3), will be administered via single intramuscular injection.
Experimental: FLU/COVm_Dose Level 2; Participants receive a single intramuscular administration of the investigational mRNA Seasonal Flu/COVID-19 combination vaccine at dose level 2 (Medium dose).	Biological: Investigational mRNA Seasonal Flu/COVID-19 Combination (Flu/COVm) Vaccine; Flu/COVm Vaccine with multiple dose levels (Dose Level 1, Dose Level 2, and Dose Level 3), will be administered via single intramuscular injection.
Experimental: FLU/COVm_Dose Level 3; Participants receive a single intramuscular administration of the investigational mRNA Seasonal Flu/COVID-19 combination vaccine at dose level 3 (Highest dose).	Biological: Investigational mRNA Seasonal Flu/COVID-19 Combination (Flu/COVm) Vaccine; Flu/COVm Vaccine with multiple dose levels (Dose Level 1, Dose Level 2, and Dose Level 3), will be administered via single intramuscular injection.
Active Comparator: Licensed Seasonal Influenza Vaccine Group; Participants receive a single intramuscular administration of a licensed seasonal Flu vaccine.	Biological: Licensed Seasonal Influenza Vaccine; License Seasonal Influenza Vaccine will be administered as a single intramuscular dose.
Active Comparator: Licensed COVID-19 Vaccine Group; Participants receive a single intramuscular administration of a licensed COVID-19 vaccine.	Biological: Licensed COVID-19 Vaccine; Licensed COVID-19 Vaccine will be administered as a single intramuscular dose.

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Number of Participants with an Increase in Toxicity Grade of Laboratory Value Abnormalities Following Administration of the Study Intervention	The assessed toxicity grades for laboratory value abnormalities will be defined as follows: Grade 1 = Mild, Grade 2 = Moderate, Grade 3 = Severe, and Grade 4 = Potentially life-threatening.	Day 1 to Day 3
Number of Participants with an Increase in Toxicity Grade of Laboratory Value Abnormalities following Administration of Study Intervention		Day 1 to Day 8
Number of Participants with an Increase in Toxicity Grade of Laboratory Value Abnormalities following Administration of Study Intervention		Day 1 to Day 29
Number of Participants with Solicited Administration Site Adverse Events (AEs)	The solicited administration site AEs considered are pain, redness, swelling and lymphadenopathy.	Day 1 to Day 7
Number of Participants with Solicited Systemic AEs	The solicited systemic AEs considered are fever, headache, fatigue, myalgia, arthralgia and chills.	Day 1 to Day 7
Number of Participants with Unsolicited AEs	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.	Day 1 to Day 28
Number of Participants with Serious Adverse Events (SAEs)	A SAE is an AE which results in death, is life-threatening, requires inpatient hospitalization or prolongation of existing hospitalization, results in disability/incapacity, or other situations that are considered serious per medical or scientific judgment.	Day 1 to Day 181
Number of Participants with Adverse Events of Special Interest (AESIs)	The following events are considered as AESI in this study: severe hypersensitivity reactions within 24 hours after study intervention administration, Aminotransferase elevation; myocarditis/pericarditis within 6 weeks after study intervention administration and potential immune-mediated diseases (pIMDs).	Day 1 to Day 181
Number of Participants with Medically Attended Adverse Events (MAAEs)	A MAAE is an AE for which the participant received medical attention including any symptom or illness requiring hospitalization, or an emergency room visit, or visit to/by a healthcare professional.	Day 1 to Day 181

Secondary Outcome Measures

Outcome Measure	Time Frame
Percentage of Participants with Antigen 1 Seroprotection Rate (SPR)	At Day 1 and Day 29
Geometric Mean Titer (GMT) Of Antigen 1 Titer	At Day 29
Percentage of Participants with Antigen 1 Seroconversion Rate (SCR)	Day 1 to Day 29
Geometric Mean Increase (GMI) of Antigen 1 Titer	Day 1 to Day 29
GMT Of Antigen 2 Titer	At Day 29
Percentage of Participants with Antigen 2 SCR	Day 1 to Day 29
GMI of Antigen 2 Titer	Day 1 to Day 29
GMT ratio of serum neutralization titers against pseudovirus bearing spike from SARS-CoV-2 vaccine matched variant(s)	At Day 29
Percentage of participants with seroresponse of neutralization titers against pseudovirus bearing spike from SARS-CoV-2 vaccine matched variant(s)	Day 1 to Day 29
GMI of neutralization titers against pseudovirus bearing spike from SARS-CoV-2 vaccine matched variant(s)	Day 1 to Day 29

Collaborators and Investigators

• Sponsor: GlaxoSmithKline

Study record dates

Study Major Dates

• Study Start (Actual): March 9, 2026
• Primary Completion (Estimated): December 3, 2026
• Study Completion (Estimated): June 3, 2027

Study Registration Dates

• First Submitted: March 6, 2026
• First Submitted That Met QC Criteria: March 6, 2026
• First Posted (Actual): March 11, 2026

Study Record Updates

• Last Update Posted (Actual): March 27, 2026
• Last Update Submitted That Met QC Criteria: March 23, 2026
• Last Verified: March 1, 2026

More Information

Terms related to this study

• Keywords: SARS-CoV-2; older adults; Influenza; COVID-19; immunogenicity; combination vaccine; mRNA vaccine
• Additional Relevant MeSH Terms: Respiratory Tract Infections; Infections; Orthomyxoviridae Infections; RNA Virus Infections; Virus Diseases; Respiratory Tract Diseases; Lung Diseases; Pneumonia, Viral; Pneumonia; Coronavirus Infections; Coronaviridae Infections; Nidovirales Infections; COVID-19; Influenza, Human; Biological Products; Complex Mixtures; Vaccines
• Other Study ID Numbers: 300768

Plan for Individual participant data (IPD)

• Plan to Share Individual Participant Data (IPD)?: YES
• IPD Plan Description: Study Sponsor 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
• IPD Sharing Time Frame: Anonymized IPD will be made available within 6 months of publication of primary, key secondary and safety results for studies in product with approved indication(s) or asset(s) with development terminated across all indications.
• IPD Sharing Access Criteria: Anonymized IPD is shared with researchers whose proposals are approved by an Independent Review Panel and after a Data Sharing Agreement is in place. Access is provided for an initial period of 12 months, but an extension may be granted, when justified, for up to 6 months.
• IPD Sharing Supporting Information Type: STUDY_PROTOCOL; SAP; ICF; CSR

Drug and device information, study documents

• Studies a U.S. FDA-regulated drug product: Yes
• Studies a U.S. FDA-regulated device product: No