NCT06602531

Brief Summary

The goal of this clinical trial is to evaluate the safety and immune responses of three different dose levels a self-amplifying RNA pandemic influenza vaccine (ARCT-2304) in adults. The key objectives of the study are:

  • To evaluate safety and reactogenicity of different dose levels of the ARCT-2304 vaccine
  • To describe the Immune responses of different dose levels of the ARCT-2304 vaccine as measured by hemagglutination inhibition (HAI) and neuraminidase enzyme-linked lectin (ELLA) antibody responses Researchers will compare the results with licensed influenza vaccines to select the most optimal dose level and schedule for vaccine administration in terms of safety and immunogenicity for further development of the vaccine. Participants will receive 2 doses of the ARCT-2304 vaccine or 1 dose of licensed influenza vaccine and 1 dose of placebo. They will be asked:
  • to complete a daily diary for 7 days after each vaccination, answering questions how they have been feeling on that day.
  • to provide blood samples at each visit in the clinic
  • to comply with all study visits and procedures (e.g., be available for planned telephone contacts and unscheduled clinic visits, if required)

Trial Health

87
On Track

Trial Health Score

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

Enrollment
212

participants targeted

Target at P75+ for phase_1

Timeline
Completed

Started Dec 2024

Geographic Reach
1 country

4 active sites

Status
completed

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

First Submitted

Initial submission to the registry

September 16, 2024

Completed
3 days until next milestone

First Posted

Study publicly available on registry

September 19, 2024

Completed
3 months until next milestone

Study Start

First participant enrolled

December 10, 2024

Completed
6 months until next milestone

Primary Completion

Last participant's last visit for primary outcome

June 13, 2025

Completed
6 months until next milestone

Study Completion

Last participant's last visit for all outcomes

December 5, 2025

Completed
Last Updated

January 30, 2026

Status Verified

January 1, 2026

Enrollment Period

6 months

First QC Date

September 16, 2024

Last Update Submit

January 28, 2026

Conditions

Influenza, Human

Keywords

InfluenzaVaccine

Outcome Measures

Primary Outcomes (7)

  • Percentage of participants reporting local Adverse Events

    Solicited local AEs including injection site pain, erythema, and swelling

    For 7 days following each study vaccination

  • Percentage of participants reporting systemic Adverse Events

    Solicited systemic AEs including fatigue, headache, myalgia, arthralgia, nausea, dizziness, chills, and fever

    For 7 days following each study vaccination

  • Percentage of participants reporting unsolicited Adverse Events

    Spontaneously reported adverse events and as elicited by investigational site staff

    For 28 days following each study vaccination

  • Percentage of participants reporting laboratory or vital signs abnormalities

    Abnormal clinically significant values

    For 28 days following each study vaccination

  • Percentage of participants reporting serious adverse events, medically attended adverse events, adverse events of special interest, and adverse events leading to early termination

    Spontaneously reported adverse events and as elicited by investigational site staff

    For 28 days following each study vaccination

  • Serum hemagglutination inhibition (HAI) antibody levels against the HA glycoprotein

    HAI antibody levels expressed as GMT, GMFRs, SCRs, and HAI titers

    For 28 days following study second vaccination

  • Serum neuraminidase enzyme-linked lectin (ELLA) assay antibody levels against the NA glycoproteins

    ELLA antibody levels expressed as GMT, GMFRs, SCRs, and HAI titers

    For 28 days following study second vaccination

Secondary Outcomes (4)

  • Percentage of participants reporting serious adverse events, medically attended adverse events, adverse events of special interest, and adverse events leading to early termination

    For 240 days following study vaccination

  • Serum hemagglutination inhibition (HAI) antibody levels against the HA glycoprotein

    For 240 days following study vaccination

  • Serum neuraminidase enzyme-linked lectin (ELLA) assay antibody levels against the NA glycoproteins

    For 240 days following study vaccination

  • Serum neutralizing (MN) antibody levels against the HA glycoprotein

    For 28 days following study second vaccination

Study Arms (16)

Low dose of ARCT-2304, Schedule 1, Young Adults

EXPERIMENTAL

Low dose of ARCT-2304 administered through intramuscular injection in the deltoid muscle. Interventions: 2-dose regimen, schedule 1 Investigational Vaccine: ARCT-2304

Biological: ARCT-2304

Mid dose of ARCT-2304, Schedule 1, Young Adults

EXPERIMENTAL

Mid dose of ARCT-2304 administered through intramuscular injection in the deltoid muscle. Interventions: 2-dose regimen, schedule 1 Investigational Vaccine: ARCT-2304

Biological: ARCT-2304

High dose of ARCT-2304, Schedule 1, Young Adults

EXPERIMENTAL

High dose of ARCT-2304 administered through intramuscular injection in the deltoid muscle. Interventions: 2-dose regimen, schedule 1 Investigational Vaccine: ARCT-2304

Biological: ARCT-2304

Control, Schedule 1, Young Adults

ACTIVE COMPARATOR

Control Vaccine (dose 1) and placebo (dose 2) administered through intramuscular injection in the deltoid muscle. Interventions: 2-dose regimen, schedule 1 Investigational Vaccine: Comparator vaccine younger adult and saline placebo vaccine

Biological: Control vaccine younger adultsOther: Placebo Vaccine

Low dose of ARCT-2304, Schedule 1, Older Adults

EXPERIMENTAL

Low dose of ARCT-2304 administered through intramuscular injection in the deltoid muscle. Interventions: 2-dose regimen, schedule 1 Investigational Vaccine: ARCT-2304

Biological: ARCT-2304

Mid dose of ARCT-2304, Schedule 1, Older Adults

EXPERIMENTAL

Mid dose of ARCT-2304 administered through intramuscular injection in the deltoid muscle. Interventions: 2-dose regimen, schedule 1 Investigational Vaccine: ARCT-2304

Biological: ARCT-2304

High dose of ARCT-2304, Schedule 1, Older Adults

EXPERIMENTAL

High dose of ARCT-2304 administered through intramuscular injection in the deltoid muscle. Interventions: 2-dose regimen, schedule 1 Investigational Vaccine: ARCT-2304

Biological: ARCT-2304

Control, Schedule 1, Older Adults

ACTIVE COMPARATOR

Older Adults Control Vaccine (dose 1) and placebo (dose 2) administered through intramuscular injection in the deltoid muscle. Interventions: 2-dose regimen, schedule 1 Investigational Vaccine: Comparator vaccine older adult and saline

Biological: Control vaccine older adultsOther: Placebo Vaccine

Low dose of ARCT-2304, Schedule 2, Young Adults

EXPERIMENTAL

Low dose of ARCT-2304 administered through intramuscular injection in the deltoid muscle. Interventions: 2-dose regimen, schedule 2 Investigational Vaccine: ARCT-2304

Biological: ARCT-2304

Mid dose of ARCT-2304, Schedule 2, Young Adults

EXPERIMENTAL

Mid dose of ARCT-2304 administered through intramuscular injection in the deltoid muscle. Interventions: 2-dose regimen, schedule 2 Investigational Vaccine: ARCT-2304

Biological: ARCT-2304

High dose of ARCT-2304, Schedule 2, Young Adults

EXPERIMENTAL

High dose of ARCT-2304 administered through intramuscular injection in the deltoid muscle. Interventions: 2-dose regimen, schedule 2 Investigational Vaccine: ARCT-2304

Biological: ARCT-2304

Control, Schedule 2, Young Adults

ACTIVE COMPARATOR

Young Adults Control Vaccine (dose 1) and placebo (dose 2) administered through intramuscular injection in the deltoid muscle. Interventions: 2-dose regimen, schedule 2 Investigational Vaccine: Comparator vaccine younger adult and saline placebo vaccine

Biological: Control vaccine younger adultsOther: Placebo Vaccine

Low dose of ARCT-2304, Schedule 2, Older Adults

EXPERIMENTAL

Low dose of ARCT-2304 administered through intramuscular injection in the deltoid muscle. Interventions: 2-dose regimen, schedule 2 Investigational Vaccine: ARCT-2304

Biological: ARCT-2304

Mid dose of ARCT-2304, Schedule 2, Older Adults

EXPERIMENTAL

Mid dose of ARCT-2304 administered through intramuscular injection in the deltoid muscle. Interventions: 2-dose regimen, schedule 2 Investigational Vaccine: ARCT-2304

Biological: ARCT-2304

High dose of ARCT-2304, Schedule 2, Older Adults

EXPERIMENTAL

High dose of ARCT-2304 administered through intramuscular injection in the deltoid muscle. Interventions: 2-dose regimen, schedule 2 Investigational Vaccine: ARCT-2304

Biological: ARCT-2304

Control, Schedule 2, Older Adults

ACTIVE COMPARATOR

Older Adults Control Vaccine (dose 1) and placebo (dose 2) administered through intramuscular injection in the deltoid muscle. Interventions: 2-dose regimen, schedule 2 Investigational Vaccine: Comparator vaccine older adult and saline placebo vaccine

Biological: Control vaccine older adultsOther: Placebo Vaccine

Interventions

ARCT-2304BIOLOGICAL

Each participant will receive 2-dose regimen intramuscular (IM) dose into the deltoid muscle.

Also known as: Self-Amplifying mRNA pandemic Influenza vaccine
High dose of ARCT-2304, Schedule 1, Older AdultsHigh dose of ARCT-2304, Schedule 1, Young AdultsHigh dose of ARCT-2304, Schedule 2, Older AdultsHigh dose of ARCT-2304, Schedule 2, Young AdultsLow dose of ARCT-2304, Schedule 1, Older AdultsLow dose of ARCT-2304, Schedule 1, Young AdultsLow dose of ARCT-2304, Schedule 2, Older AdultsLow dose of ARCT-2304, Schedule 2, Young AdultsMid dose of ARCT-2304, Schedule 1, Older AdultsMid dose of ARCT-2304, Schedule 1, Young AdultsMid dose of ARCT-2304, Schedule 2, Older AdultsMid dose of ARCT-2304, Schedule 2, Young Adults
Control vaccine younger adultsBIOLOGICAL

Each participant will receive one intramuscular (IM) dose into the deltoid muscle.

Also known as: Influenza vaccine
Control, Schedule 1, Young AdultsControl, Schedule 2, Young Adults
Control vaccine older adultsBIOLOGICAL

Each participant will receive one intramuscular (IM) dose into the deltoid muscle.

Also known as: Influenza vaccine
Control, Schedule 1, Older AdultsControl, Schedule 2, Older Adults
Placebo VaccineOTHER

Each participant will receive one intramuscular (IM) dose into the deltoid muscle.

Also known as: saline
Control, Schedule 1, Older AdultsControl, Schedule 1, Young AdultsControl, Schedule 2, Older AdultsControl, Schedule 2, Young Adults

Eligibility Criteria

Age18 Years - 80 Years
Sexall
Healthy VolunteersYes
Age GroupsAdult (18-64), Older Adult (65+)

You may qualify if:

  • Individuals are male or female adults 18-80 years of age.
  • Healthy participants or participants with pre-existing stable medical conditions.
  • Individuals of childbearing potential must be willing to adhere to contraceptive requirements.

You may not qualify if:

  • Individuals with acute medical conditions or febrile illness, including body temperature ≥100.4°F (≥38.0°C measured by any method) within 3 days prior to randomization.
  • Individuals with a known history of severe hypersensitivity reactions, including anaphylaxis, or other significant adverse reactions to any mRNA vaccine, influenza vaccine, or excipients.
  • Individuals with a history of myocarditis, pericarditis, myopericarditis, or cardiomyopathy.
  • Individuals who received any influenza vaccine within 3 months prior to first vaccine administration or plan to receive an influenza vaccine during the study period.
  • Individuals who have received mRNA vaccination within 60 days before the first vaccine administration.
  • Individuals who have received or plan to receive an A/H5N1 influenza vaccine and/or individuals who had substantial exposure to or direct contact with poultry, wild birds, live cattle, or raw milk.

Contact the study team to confirm eligibility.

Sponsors & Collaborators

Study Sites (4)

Velocity Clinical Research

La Mesa, California, 91942, United States

Location

Velocity Clinical Research

San Bernardino, California, 92408, United States

Location

Tekton Research

Longmont, Colorado, 80501, United States

Location

CTI Clinical Research Center

Cincinnati, Ohio, 45212, United States

Location

MeSH Terms

Conditions

Influenza, Human

Interventions

Influenza VaccinesSodium Chloride

Condition Hierarchy (Ancestors)

Respiratory Tract InfectionsInfectionsOrthomyxoviridae InfectionsRNA Virus InfectionsVirus DiseasesRespiratory Tract Diseases

Intervention Hierarchy (Ancestors)

Viral VaccinesVaccinesBiological ProductsComplex MixturesChloridesHydrochloric AcidChlorine CompoundsInorganic ChemicalsSodium Compounds

Study Officials

  • Clinical Program Director

    Arcturus Therapeutics

    STUDY DIRECTOR

Study Design

Study Type
interventional
Phase
phase 1
Allocation
RANDOMIZED
Masking
QUADRUPLE
Who Masked
PARTICIPANT, CARE PROVIDER, INVESTIGATOR, OUTCOMES ASSESSOR
Masking Details
Observer blind
Purpose
PREVENTION
Intervention Model
PARALLEL
Sponsor Type
INDUSTRY
Responsible Party
SPONSOR

Study Record Dates

First Submitted

September 16, 2024

First Posted

September 19, 2024

Study Start

December 10, 2024

Primary Completion

June 13, 2025

Study Completion

December 5, 2025

Last Updated

January 30, 2026

Record last verified: 2026-01

Data Sharing

IPD Sharing
Will not share

Individual participant data will only be made available to study investigators at this time.

Locations

US(4)