Study of an RSV-hMPV-PIV3 Trivalent Vaccine Candidate VXB-251 in Older Adults

NCT07295028 | Active Not Recruiting Phase 1 DMC

• 1 other identifier: VXB251-001
• Study Type: interventional
• Target: 240
• Locations: 1 country
• Sites: 6

Brief Summary

This study is being done to find out how safe and effective a new combined vaccine candidate, called VXB-251, is for older adults. The vaccine candidate is designed to protect against three common viruses that can cause respiratory tract infections:

• RSV (respiratory syncytial virus)
• hMPV (human metapneumovirus)
• PIV3 (parainfluenza virus type 3) Two components of this vaccine (RSV and hMPV) have already been tested in people before, as part of another study for a two-in-one vaccine. However, this is the first time that the PIV3 component and all three components together (RSV, hMPV, and PIV3) are being tested in people. The vaccine candidate will be given as a single intramuscular injection. The study will also test unlicensed comparator vaccines and a placebo (a substance that looks like the real vaccine but doesn't contain any active ingredients) that target none, one or two of these viruses to see whether combining all three components affects safety or how well the immune system responds.

Conditions

Lower Respiratory Tract Disease; Healthy Participants

Keywords

RSV; hMPV; PIV3; Multipathogen respiratory virus vaccines

Outcome Measures

Primary Outcomes (3)

• Proportion of Participants With 1 or More Unsolicited Adverse Events (AEs)

  1 month after IMP injection

• Proportion of Participants With 1 or More Serious Adverse Events (SAEs), AEs of Special Interest (AESIs), and Premature Discontinuation Associated AEs (PDAEs)

  1 month after IMP injection

• Proportion of Participants With 1 or More Solicited AEs

  7 days after IMP injection

Secondary Outcomes (10)

• Proportion of Participants With Serious Adverse Events (SAEs), AEs of Special Interest (AESIs), and Premature Discontinuation Associated AEs (PDAEs)

  6 and 12 months after IMP injection

• Proportion of Participants With 1 or More Severe Solicited AEs

  7 days after IMP injection

• Geometric Mean Fold Increase (GMFI) of RSV-A, RSV-B, hMPV-A, hMPV-B, and PIV3 Serum Neutralizing Antibody Titers

  Pre-injection baseline to 1 month, 6 months, and 12 months, after IMP injection

• Geometric Mean Titers (GMTs) of RSV-A, RSV-B, hMPV-A, hMPV-B, and PIV3 Serum Neutralizing Antibody Titers

  Pre-injection baseline to 1 month, 6 months, and 12 months after IMP injection

• Proportion of Participants with Sero-response Greater Than or Equal to (>=) 4-fold (SRR-4) and 8-fold (SRR-8) Increase from Baseline in Neutralizing Antibody Titers for RSV-A, RSV-B, hMPV-A, hMPV-B, and PIV3

  Pre-injection baseline up to 1 month, 6 months, and 12 months after IMP injection

Study Arms (8)

VXB-251, low dose

EXPERIMENTAL

Biological: trivalent (RSV/hMPV/PIV3) vaccine candidate

VXB-251, medium dose

EXPERIMENTAL

Biological: trivalent (RSV/hMPV/PIV3) vaccine candidate

VXB-251, high dose

EXPERIMENTAL

Biological: trivalent (RSV/hMPV/PIV3) vaccine candidate

VXB-241

EXPERIMENTAL

Biological: bivalent (RSV/hMPV) unlicensed comparator

VXB-213

EXPERIMENTAL

Biological: monovalent (RSV) unlicensed comparator

VXB-221

EXPERIMENTAL

Biological: Biological/Vaccine: monovalent (hMPV) unlicensed comparator

VXB-232

EXPERIMENTAL

Biological: monovalent (PIV3) unlicensed comparator

Placebo

PLACEBO COMPARATOR

Other: Placebo

Interventions

Placebo OTHER

diluent, single, IM injection.

Placebo

trivalent (RSV/hMPV/PIV3) vaccine candidate BIOLOGICAL

VXB-251 low dose, single, IM injection.

VXB-251, low dose

bivalent (RSV/hMPV) unlicensed comparator BIOLOGICAL

VXB-241 medium dose, single, IM injection.

VXB-241

monovalent (RSV) unlicensed comparator BIOLOGICAL

VXB-213 medium dose, single, IM injection.

VXB-213

Biological/Vaccine: monovalent (hMPV) unlicensed comparator BIOLOGICAL

VXB-221 medium dose, single, IM injection.

VXB-221

monovalent (PIV3) unlicensed comparator BIOLOGICAL

VXB-232 medium dose, single, IM injection.

VXB-232

Eligibility Criteria

• Age: 60 Years - 83 Years
• Sex: all
• Healthy Volunteers: Yes
• Age Groups: Adult (18-64), Older Adult (65+)

You may qualify if:

• Evidence of signed and dated participant informed consent form (PICF) prior to any study procedure, indicating that the subject has been informed of all pertinent aspects of the study.
• Willingness and ability to comply with the planned study visits and calls, procedures, and restrictions for the duration of the study.

You may not qualify if:

• Non-smoker or occasional smoker, defined as smoking less than 10 nicotine-containing cigarettes/ vapes/cigars/pipe fills per week.
• Contraception and childbearing/conception potential: only female participants with non-childbearing potential will be included. Male participants in a relationship with a female partner of childbearing potential must be willing to use a double contraceptive method together with their female partner for at least 4 weeks before and 12 weeks after the IMP injection at Visit 2 (day 1).
• Body mass index (BMI) ≥ 17.0 kg/m2 and ≤ 35.0 kg/m2.
• History of RSV, hMPV, and/or PIV3 infection affecting the participant and/or the participant's household in the previous 12 months.
• History of autoimmune disease (AID) or possibly autoimmune disease (pAID) requiring therapeutic intervention, even if stable and well controlled, including, but not limited to, systemic lupus erythematosus, autoimmune arthritis/rheumatoid arthritis, Guillain-Barré syndrome, multiple sclerosis, Sjögren's syndrome, idiopathic thrombocytopenia purpura, glomerulonephritis, autoimmune thyroiditis, temporal arteritis, psoriasis, insulin-dependent diabetes mellitus, celiac disease.
• Confirmed or suspected immunodeficiency, even if stable and well controlled.
• Ongoing severe asthma. Other allergic diseases (e.g., allergic rhinitis, atopic dermatitis / eczema, mild to moderate asthma, food allergies) are allowed at the investigator's or delegate's discretion.
• History of significant allergic reaction (e.g., anaphylaxis, hypersensitivity, angioedema) to medication or food or known allergy to vaccine, or any excipients in the formulation, and latex.
• History of severe AE associated with vaccine administration.
• Ongoing disorders of coagulation, which contraindicate IM injections.
• Donation or loss of ≥ 500 mL whole blood on the previous 2 months, and/or donation of plasma in the previous 1 week, and/or intention to donate blood or plasma during the study.
• Positive serum test results indicating ongoing HIV, HBV and/or HCV infection, and/or documented ongoing HIV, HBV, or HCV infection.
• Other poorly controlled and/or impactful chronic disease. A disease is defined as poorly controlled if it requires meaningful change in therapy and/or unplanned medical visit(s) in the previous 3 months. A disease is defined as impactful if, in the investigator's judgment, it meaningfully affects the participant's ability to manage self-care and/or activities of daily living.
• Disease expected to prevent completion of the study (i.e. to rapidly deteriorate within the timeframe of the study).
• Prior treatments.

Sponsors & Collaborators

• Vicebio Australia Proprietary Limited: lead

Study Sites (6)

University of Sunshine Coast, South Bank

Brisbane, Australia

Location

Emeritus Research

Camberwell, Australia

Location

Momentum Clinical Research

Darlinghurst, Australia

Location

Veritus Research

Melbourne, Australia

Location

University of the Sunshine Coast

Morayfield, Australia

Location

University of the Sunshine Coast, Sippy Downs

Sippy Downs, Australia

Location

MeSH Terms

Interventions

Biological Products

Intervention Hierarchy (Ancestors)

Complex Mixtures

Study Officials

• Nischal Sahai, MD

  University of the Sunshine Coast, South Bank

  PRINCIPAL INVESTIGATOR

• Stephanie Wallace, MD

  University of the Sunshine Coast, Sippy Downs

  PRINCIPAL INVESTIGATOR

• Christopher Moller, MD

  University of the Sunshine Coast, Morayfield

  PRINCIPAL INVESTIGATOR

• Rebecca Wolf, MD

  Veritus Research

  PRINCIPAL INVESTIGATOR

• Rishi Shah, MD

  Emeritus Research

  PRINCIPAL INVESTIGATOR

• Juliet Freeborn, MD

  Momentum Clinical Research

  PRINCIPAL INVESTIGATOR

Study Design

• Study Type: interventional
• Phase: phase 1
• Allocation: RANDOMIZED
• Masking: DOUBLE
• Who Masked: PARTICIPANT, INVESTIGATOR
• Masking Details: Double
• Purpose: PREVENTION
• Intervention Model: SEQUENTIAL
• Sponsor Type: INDUSTRY
• Responsible Party: SPONSOR

Model Details: Stage 1 is a sequential assignment followed by Stage 2 parallel assignment.

Study Record Dates

• First Submitted: November 24, 2025
• First Posted: December 19, 2025
• Study Start: November 17, 2025
• Primary Completion: April 21, 2026
• Study Completion (Estimated): April 24, 2027
• Last Updated: April 27, 2026

Record last verified: 2025-11

Data Sharing

• IPD Sharing: Will not share

Locations

AU (6)