Recruiting

Quadrivalent Influenza HA Stem Vaccine Safety and Immune Response in Healthy Adults

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What is being tested

VRC-FLUMOS0122-00-VP (SteMos1) with and without Army Liposome Formulation containing saponin QS-21 (ALFQ) Adjuvant

Biological
Who is being recruted

From 18 to 50 Years
+50 Eligibility Criteria
See all eligibility criteria
How is the trial designed

Prevention Study

Phase 1
Interventional
Study Start: August 2025
See protocol details

Summary

Principal SponsorNational Institute of Allergy and Infectious Diseases (NIAID)
Study ContactVRC Clinic
Last updated: January 23, 2026
Sourced from a government-validated database.Claim as a partner
Study start date: August 27, 2025Actual date on which the first participant was enrolled.

This study focuses on testing a new flu vaccine called SteMos1, which aims to protect against four types of influenza viruses. The vaccine's safety, how well it is tolerated, and its ability to trigger an immune response are being evaluated. The study includes healthy adults and looks at different doses of the vaccine, both with and without an additional substance called ALFQ, which may enhance the vaccine's effectiveness. The goal is to ensure the vaccine is safe and effective, potentially leading to better flu protection in the future. Participants in this study receive two doses of the vaccine through an injection in the muscle. Researchers observe any side effects or reactions for a week following each injection and monitor for any other health issues over a month. The study measures immune responses by checking antibody levels two weeks after each dose. Some participants receive the vaccine with the ALFQ adjuvant, while others do not, allowing researchers to compare the effects. The study also explores different types of immune responses over time, contributing valuable information on how well the vaccine might work in preventing flu.

Official TitleVRC 329: A Phase I Open-Label, Clinical Trial to Evaluate the Safety, Tolerability, and Immunogenicity of a Quadrivalent Influenza HA Stem Vaccine VRC-FLUMOS0122-00-VP (STEMos1) With and Without ALFQ Adjuvant in Healthy Adults 
NCT07111078
Principal SponsorNational Institute of Allergy and Infectious Diseases (NIAID)
Study ContactVRC Clinic
Last updated: January 23, 2026
Sourced from a government-validated database.Claim as a partner

Protocol

This section provides details of the study plan, including how the study is designed and what the study is measuring.
Design Details
56 patients to be enrolledTotal number of participants that the clinical trial aims to recruit.
Prevention Study
Prevention studies aim to stop a disease from developing. They often involve people at risk and test things like vaccines, lifestyle changes, or preventive medications.

How participants are assigned to different groups/arms
In this clinical study, participants are assigned to groups based on specific criteria, such as their medical history or a doctor's recommendation. This approach ensures that treatments are given to those who may benefit the most, based on known factors.

Other Ways to Assign Participants
Randomized allocation: Participants are assigned randomly, like flipping a coin, to ensure fairness and reduce bias.
None (Single-arm trial): If the study has only one group, all participants receive the same treatment, and no allocation is needed.

How treatments are given to participants
Participants receive treatments one after another in a pre-planned sequence. The next treatment may depend on how the participant responds to the previous one.

Other Ways to Assign Treatments
Single-group assignment: Everyone gets the same treatment.
Parallel assignment: Participants are split into separate groups, each receiving a different treatment.
Cross-over assignment: Participants switch between treatments during the study.
Factorial assignment: Participants receive different combinations of treatments.
Other assignment: Treatment assignment does not follow a standard or predefined design.

How the effectiveness of the treatment is controlled
In a non placebo-controlled study, no participants receive an inert substance (placebo) to compare outcomes. Instead, all participants receive either the experimental treatment or an alternative treatment (often the Standard of Care). This method allows researchers to compare the effects of the experimental treatment with those of a different active intervention, rather than a placebo.

Other Options
Placebo-Controlled: A placebo is used to compare the effects of the experimental treatment with those of an inert substance, isolating the true treatment effect.

How the interventions assigned to participants is kept confidential
Everyone involved in the study knows which treatment is being given. This is typically used when it's not possible or necessary to hide the treatment details from participants or researchers.

Other Ways to Mask Information
Single-blind: Participants do not know which treatment they are receiving, but researchers do.
Double-blind: Neither participants nor researchers know which treatment is given.
Triple-blind: Participants, researchers, and outcome assessors do not know which treatment is given.
Quadruple-blind: Participants, researchers, outcome assessors, and care providers all do not know which treatment is given.

Eligibility

Researchers look for people who fit a certain description, called eligibility criteria: person's general health condition or prior treatments.
Criteria
Any sexBiological sex of participants that are eligible to enroll.
From 18 to 50 YearsRange of ages for which participants are eligible to join.
Healthy volunteers allowedIf individuals who are healthy and do not have the condition being studied can participate.
Criteria
22 inclusion criteria required to participate
Negative beta-human chorionic gonadotropin (beta-HCG) pregnancy test (urine or serum) on the day of enrollment (applicable to women of childbearing potential)
Agrees to use an effective means of birth control from at least 21 days prior to enrollment through the end of the study (applicable to women of childbearing potential)
Physical examination and laboratory results without clinically significant findings and a Body Mass Index (BMI) <= 35 within the 56 days before enrollment
Total lymphocyte count >= 800 cells/microliter

Show More Criteria

28 exclusion criteria prevent from participating
Receipt of any licensed influenza vaccine or lab-confirmed influenza infection within 6 months prior to enrollment.
Plan to or are required to receive the 2025-2026 or 2026-2027 licensed influenza vaccines
Live attenuated vaccines within 4 weeks prior to enrollment
Inactivated vaccines within 2 weeks prior to enrollment

Show More Criteria

Study Plan

Find out more about all the medication administered in this study, their detailed description and what they involve.
Treatment Groups
Study Objectives
5 intervention groups 

are designated in this study

This study does not include a placebo group 

Treatment Groups
Group I
Experimental
60 mcg of SteMos1 on Day 0 and Week 16

FLUMOS0122-00-VP (SteMos1) is a sterile, aqueous buffered solution supplied in 3 mL single-dose glass vials containing 0.7 +/- 0.1 mL with a vaccine concentration of 1080 mcg/mL. The ALFQ drug product is a sterile suspension that contains 240 mcg of monophosphoryl 3-deacyl Lipid A (3D-PHAD) and 120 mcg QS-21 that is vialed at 0.6 mL/vial in 3.0 mL glass vials. 0.5 mL of ALFQ adjuvant will be mixed with the 60 or 180 mcg dose of SteMos1 during preparation in the pharmacy prior to
Group II
Experimental
180 mcg of SteMos1 on Day 0 and Week 16

FLUMOS0122-00-VP (SteMos1) is a sterile, aqueous buffered solution supplied in 3 mL single-dose glass vials containing 0.7 +/- 0.1 mL with a vaccine concentration of 1080 mcg/mL. The ALFQ drug product is a sterile suspension that contains 240 mcg of monophosphoryl 3-deacyl Lipid A (3D-PHAD) and 120 mcg QS-21 that is vialed at 0.6 mL/vial in 3.0 mL glass vials. 0.5 mL of ALFQ adjuvant will be mixed with the 60 or 180 mcg dose of SteMos1 during preparation in the pharmacy prior to
Group III
Experimental
60 mcg of SteMos1 + 0.5 ml of ALFQ on Day 0 and Week 16

FLUMOS0122-00-VP (SteMos1) is a sterile, aqueous buffered solution supplied in 3 mL single-dose glass vials containing 0.7 +/- 0.1 mL with a vaccine concentration of 1080 mcg/mL. The ALFQ drug product is a sterile suspension that contains 240 mcg of monophosphoryl 3-deacyl Lipid A (3D-PHAD) and 120 mcg QS-21 that is vialed at 0.6 mL/vial in 3.0 mL glass vials. 0.5 mL of ALFQ adjuvant will be mixed with the 60 or 180 mcg dose of SteMos1 during preparation in the pharmacy prior to
Group IV
Experimental
180 mcg of SteMos1 + 0.5 ml of ALFQ on Day 0 and Week 16

FLUMOS0122-00-VP (SteMos1) is a sterile, aqueous buffered solution supplied in 3 mL single-dose glass vials containing 0.7 +/- 0.1 mL with a vaccine concentration of 1080 mcg/mL. The ALFQ drug product is a sterile suspension that contains 240 mcg of monophosphoryl 3-deacyl Lipid A (3D-PHAD) and 120 mcg QS-21 that is vialed at 0.6 mL/vial in 3.0 mL glass vials. 0.5 mL of ALFQ adjuvant will be mixed with the 60 or 180 mcg dose of SteMos1 during preparation in the pharmacy prior to
Group 5
Experimental
SteMos1 \[dose TBD based on interim analysis of data from Groups 3-4\] + 0.5 ml of ALFQ on Day 0 and Week 16

FLUMOS0122-00-VP (SteMos1) is a sterile, aqueous buffered solution supplied in 3 mL single-dose glass vials containing 0.7 +/- 0.1 mL with a vaccine concentration of 1080 mcg/mL. The ALFQ drug product is a sterile suspension that contains 240 mcg of monophosphoryl 3-deacyl Lipid A (3D-PHAD) and 120 mcg QS-21 that is vialed at 0.6 mL/vial in 3.0 mL glass vials. 0.5 mL of ALFQ adjuvant will be mixed with the 60 or 180 mcg dose of SteMos1 during preparation in the pharmacy prior to
Study Objectives
Primary Objectives

Solicited reactogenicity will be evaluated using a 7-day diary card. Assessment of vaccine safety will include clinical observation and monitoring of hematological and chemical parameters at clinical visits throughout the study.

Solicited reactogenicity will be evaluated using a 7-day diary card. Assessment of vaccine safety will include clinical observation and monitoring of hematological and chemical parameters at clinical visits throughout the study.

Solicited reactogenicity will be evaluated using a 7-day diary card. Assessment of vaccine safety will include clinical observation and monitoring of hematological and chemical parameters at clinical visits throughout the study.

Solicited reactogenicity will be evaluated using a 7-day diary card. Assessment of vaccine safety will include clinical observation and monitoring of hematological and chemical parameters at clinical visits throughout the study.
Secondary Objectives

Binding antibody responses

Binding antibody responses

Binding antibody responses

Binding antibody responses

Study Centers

These are the hospitals, clinics, or research facilities where the trial is being conducted. You can find the location closest to you and its status.
This study has 1 location
Recruiting
National Institutes of Health Clinical CenterBethesda, United StatesSee the location
Recruiting
One Study Center
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