NCT06556147

Brief Summary

The main purposes of this study are to assess the safety, reactogenicity and immunogenicity of 4 dose levels of the bivalent combination Respiratory Syncytial Virus (RSV) / human Metapneumovirus (hMPV) vaccine candidate VXB-241 when administered as a single-dose regimen to healthy adults 60 to 83 years of age, and to assess the impact of revaccination approximately 1 year later.

Trial Health

75
On Track

Trial Health Score

Automated assessment based on enrollment pace, timeline, and geographic reach

Enrollment
144

participants targeted

Target at P75+ for phase_1 healthy-volunteers

Timeline
11mo left

Started Aug 2024

Longer than P75 for phase_1 healthy-volunteers

Geographic Reach
1 country

4 active sites

Status
active not recruiting

Health score is calculated from publicly available data and should be used for screening purposes only.

Trial Relationships

Click on a node to explore related trials.

Study Timeline

Key milestones and dates

Study Progress68%
Aug 2024May 2027

First Submitted

Initial submission to the registry

August 13, 2024

Completed
Same day until next milestone

Study Start

First participant enrolled

August 13, 2024

Completed
2 days until next milestone

First Posted

Study publicly available on registry

August 15, 2024

Completed
6 months until next milestone

Primary Completion

Last participant's last visit for primary outcome

February 14, 2025

Completed
2.2 years until next milestone

Study Completion

Last participant's last visit for all outcomes

May 1, 2027

Expected
Last Updated

May 20, 2026

Status Verified

May 1, 2026

Enrollment Period

6 months

First QC Date

August 13, 2024

Last Update Submit

May 18, 2026

Conditions

Keywords

Human MetapneumovirusRespiratory Syncytial VirusVaccine

Outcome Measures

Primary Outcomes (4)

  • Proportion of Older Adult Participants With 1 or More Unsolicited AEs

    1 month after first IMP injection (Days 1 to 30)

  • Proportion of Older Adult Participants With 1 or More Solicited AEs

    7 days after first IMP injection (Days 1 to 8)

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

    GMFI is defined as geometric mean of ratios of specific antibody titer/concentration at each post-vaccination time point over pre-vaccination baseline.

    Pre-injection baseline to 1 month (Day 30) after first IMP injection

  • Ratio of Dose-response Curves for GMFIs of RSV-A, RSV-B, hMPV-A and hMPV-B Serum Neutralizing Antibody Titers in Older Adults

    Ratio of VXB-241 dose versus GMFI of RSV-A, RSV-B, hMPV-A and hMPV-B will be calculated.

    Pre-injection baseline to 1 month (Day 30) after first IMP injection

Secondary Outcomes (16)

  • Proportion of Older Adult Participants With 1 or More Unsolicited AEs and With 1 or More Severe Unsolicited AE

    1 month after first IMP injection (Days 1 to 30) and 1 month after second IMP injection (revaccination, Days 364 to 394)

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

    1 month after first IMP injection (Days 1 to 30) and 1 month after second IMP injection (revaccination, Days 364 to394), and throughout follow-up (Days 1 to 720)

  • Mean Change From Baseline for Abnormal and Severe Abnormal Hematology Laboratory Values for Hemoglobin in Older Adults

    7 days (Day 8) and 1 month (Day 30) after first IMP injection, and 1 month (Day 394) after second IMP injection (revaccination

  • Mean Change From Baseline for Abnormal and Severe Abnormal Hematology Laboratory Values for Red Blood Cells, White Blood Cells, and Platelet Count in Older Adults

    7 days (Day 8) and 1 month (Day 30) after first IMP injection, and 1 month (Day 394) after second IMP injection (revaccination

  • Mean Change From Baseline for Abnormal and Severe Abnormal Blood Chemistry Laboratory Values for Alanine Transaminase (ALT), Aspartate Transaminase (AST), and Alkaline Phosphatase in Older Adults

    7 days (Day 8) and 1 month (Day 30) after first IMP injection, and 1 month (Day 394) after second IMP injection (revaccination

  • +11 more secondary outcomes

Study Arms (14)

Stage 1, Day 1, Sequential Cohort 1

EXPERIMENTAL

Younger and older adult participants will receive VXB-241 60 mcg (low dose) or Placebo, intramuscularly (IM), once on Day 1.

Biological: VXB-241 60 mcg (Low Dose)Other: Placebo

Stage 1, Day 1, Sequential Cohort 2

EXPERIMENTAL

Younger and older adult participants will receive VXB-241 120 mcg (medium dose) or Placebo, IM, once on Day 1.

Biological: VXB-241 120 mcg (Medium Dose)Other: Placebo

Stage 1, Day 1, Sequential Cohort 3

EXPERIMENTAL

Younger and older adult participants will receive VXB-241 240 mcg (medium-high dose) or Placebo, IM, once on Day 1.

Biological: VXB-241 240 mcg (Medium-high Dose)Other: Placebo

Stage 1, Day 1, Sequential Cohort 4

EXPERIMENTAL

Younger and older adult participants will receive VXB-241 480 mcg (high dose) or Placebo, IM, once on Day 1.

Biological: VXB-241 480 mcg (High Dose)Other: Placebo

Stage 2, Day 1, Concurrent Group 1a

EXPERIMENTAL

Older adult participants will receive VXB-241 60 mcg (low dose), IM, once on Day 1.

Biological: VXB-241 60 mcg (Low Dose)

Stage 2, Day 1, Concurrent Group 1b

EXPERIMENTAL

Older adult participants will receive VXB-241 120 mcg (medium dose), IM, once on Day 1.

Biological: VXB-241 120 mcg (Medium Dose)

Stage 2, Day 1, Concurrent Group 1c

EXPERIMENTAL

Older adult participants will receive VXB-241 240 mcg (medium-high dose), IM, once on Day 1.

Biological: VXB-241 240 mcg (Medium-high Dose)

Stage 2, Day 1, Concurrent Group 1d

EXPERIMENTAL

Older adult participants will receive VXB-241 480 mcg (high dose), IM, once on Day 1.

Biological: VXB-241 480 mcg (High Dose)

Stage 2, Day 1, Concurrent Group 2a

ACTIVE COMPARATOR

Older adult participants will receive Arexvy 120 mcg, IM, once on Day 1.

Biological: Arexvy 120 mcg

Stage 2, Day 1, Concurrent Group 3a

PLACEBO COMPARATOR

Older adult participants will receive Placebo, IM, once on Day 1.

Other: Placebo

Group 1e: VXB-241 Revaccination in VXB-241 Recipients

EXPERIMENTAL

Approximately 50% of the older adult participants who received VXB-241 240 mcg, will receive VXB-241 240 mcg, IM, (based on 1 month post 1st IMP injection results), once on Day 364 in the second year of the study.

Biological: VXB-241 240 mcg

Group 1f: Placebo Revaccination in VXB-241 Recipients

PLACEBO COMPARATOR

Approximately 50% of the older adult participants who received VXB-241 (any dose level), will receive Placebo, IM, once on Day 364 in the second year of the study.

Other: Placebo

Group 2b: Placebo Arexvy Revaccination

PLACEBO COMPARATOR

All older adult participants who received Arexvy 120 mcg will receive Placebo revaccination, IM, once on Day 364 in the second year of the study.

Other: Placebo

Group 3b: VXB-241

EXPERIMENTAL

All older adult participants who received Placebo will receive VXB-241 240 mcg (based on 1 month post 1st IMP injection results), IM, once on Day 364 in the second year of the study.

Biological: VXB-241 240 mcg

Interventions

VXB-241 low dose, single, IM injection.

Stage 1, Day 1, Sequential Cohort 1Stage 2, Day 1, Concurrent Group 1a

VXB-241 medium dose, single, IM injection.

Stage 1, Day 1, Sequential Cohort 2Stage 2, Day 1, Concurrent Group 1b

VXB-241 medium-high dose, single, IM injection.

Stage 1, Day 1, Sequential Cohort 3Stage 2, Day 1, Concurrent Group 1c

VXB-241 high dose, single, IM injection.

Stage 1, Day 1, Sequential Cohort 4Stage 2, Day 1, Concurrent Group 1d
VXB-241 240 mcgBIOLOGICAL

VXB-241 240 mcg (RSV preF 120 mcg + hMPV preF 120 mcg) (based on 1 month post 1st IMP injection results) single, IM injection.

Group 1e: VXB-241 Revaccination in VXB-241 RecipientsGroup 3b: VXB-241
PlaceboOTHER

Placebo, single, IM injection.

Group 1f: Placebo Revaccination in VXB-241 RecipientsGroup 2b: Placebo Arexvy RevaccinationStage 1, Day 1, Sequential Cohort 1Stage 1, Day 1, Sequential Cohort 2Stage 1, Day 1, Sequential Cohort 3Stage 1, Day 1, Sequential Cohort 4Stage 2, Day 1, Concurrent Group 3a
Arexvy 120 mcgBIOLOGICAL

Arexvy 120 mcg, single, IM injection.

Stage 2, Day 1, Concurrent Group 2a

Eligibility Criteria

Age18 Years - 83 Years
Sexall
Healthy VolunteersYes
Age GroupsAdult (18-64), Older Adult (65+)

You may qualify if:

  • Male or female, 18 to 40 years of age (yoa) (younger adult) or 60 to 83 yoa (older adult).
  • Evidence of signed and dated participant informed consent form (PICF) prior to any study procedure, indicating that the participant 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: heterosexually active participants of childbearing potential able and willing to use a double contraceptive method for at least 4 weeks before and 12 weeks after the first IMP injection at Visit 2 (all participants of childbearing potential) and second IMP injection at Visit 6 (male older adults of childbearing potential).
  • Body Mass Index (BMI) \>=17.0 kilogram per square meter (kg/m\^2) and less than or equal to (\<=) 35.0 kg/m\^2.
  • History of RSV and/or hMPV infection affecting the participant and/or the participant's household in the previous 12 months.
  • History of autoimmune disease (AID) or potentially 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 (example, allergic rhinitis, atopic dermatitis / eczema, mild to moderate asthma, food allergies, are allowed at the investigator's or delegate's discretion).
  • History of severe allergic reaction (example, anaphylaxis) to any substance, including vaccine components and latex.
  • History of severe adverse event (AEs) associated with vaccine administration.
  • Ongoing disorders of coagulation, which contraindicate IM injections.
  • Donation or loss of \>=500 milliliter (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 for serum human immunodeficiency virus (HIV), hepatitis B virus (HBV) and/or hepatitis C virus (HCV) infection and/or documented HIV, HVB or HVC infection.
  • Other poorly controlled and/or impactful chronic disease. A disease is defined as poorly controlled if it required meaningful change in therapy and/or unplanned medical visits in the previous 3 months. A disease is defined as impactful if it has a meaningful impact on participant's self-care and/or activities of daily living.
  • Disease expected to prevent completion of the study (that is to rapidly deteriorate within the timeframe of the study).
  • Prior treatments.
  • +14 more criteria

Contact the study team to confirm eligibility.

Sponsors & Collaborators

Study Sites (4)

University of the Sunshine Coast

Morayfield, Queensland, 4506, Australia

Location

University of the Sunshine Coast

Sippy Downs, Queensland, 4556, Australia

Location

University of the Sunshine Coast

South Brisbane, Queensland, 4101, Australia

Location

Veritus Research

Bayswater, Victoria, 3153, Australia

Location

Related Publications (1)

  • Young A, Kolekar S, Mendoza CA, Jaberolansar N, Modhiran N, Webb T, McCuaig R, Kommajosyula V, Tardiota N, Dy Q, Amarilla AA, Dalrymple RL, Gillard M, Dutton JL, Magdalena J, Vandendriessche F, Smal J, Young PR, Watterson D, Hanon EJ, Chappell KJ. A second-generation molecular clamp stabilised bivalent candidate vaccine for protection against diseases caused by respiratory syncytial virus and human metapneumovirus. PLoS Pathog. 2025 Jul 17;21(7):e1013312. doi: 10.1371/journal.ppat.1013312. eCollection 2025 Jul.

MeSH Terms

Interventions

arexvy

Study Design

Study Type
interventional
Phase
phase 1
Allocation
RANDOMIZED
Masking
DOUBLE
Who Masked
PARTICIPANT, OUTCOMES ASSESSOR
Purpose
PREVENTION
Intervention Model
SEQUENTIAL
Model Details: Stage 1 is a sequential assignment followed by Stage 2 parallel assignment.
Sponsor Type
INDUSTRY
Responsible Party
SPONSOR

Study Record Dates

First Submitted

August 13, 2024

First Posted

August 15, 2024

Study Start

August 13, 2024

Primary Completion

February 14, 2025

Study Completion (Estimated)

May 1, 2027

Last Updated

May 20, 2026

Record last verified: 2026-05

Data Sharing

IPD Sharing
Will not share

Locations