A Study to Evaluate the Safety and Efficacy of mRNA-1345 Vaccine Targeting Respiratory Syncytial Virus (RSV) in Adults ≥60 Years of Age

Phase 2

Active, not recruiting

• Conditions: Respiratory Syncytial Virus
• Interventions: Drug: Placebo; Drug: mRNA-1345

• Registration Number: NCT05127434
• Lead Sponsor: ModernaTX, Inc.

Brief Summary

The main purpose of Part A of this study is to evaluate the safety and tolerability of mRNA-1345 vaccine and to demonstrate the efficacy of a single dose of mRNA-1345 vaccine in the prevention of a first episode of RSV-associated lower respiratory tract disease (RSV-LRTD) as compared with placebo from 14 days postinjection through 12 months.

The main purpose of Part B of this study is to evaluate the safety, tolerability and immunogenicity of a booster dose (BD) of mRNA-1345 administered 24 months after the primary dose.

Detailed Description

The study will be conducted in 2 phases: Phase 2 and Phase 3. In the Part A Phase 2 segment, up to 2,000 participants will be randomly assigned to receive a single injection of either mRNA-1345 vaccine at the selected dose or placebo in a 1:1 randomization ratio.

In the Part A Phase 3 segment, approximately 35,000 participants will be randomly assigned to receive a single injection of either mRNA-1345 vaccine at the selected dose or placebo in a 1:1 randomization ratio.

In the Part B substudy, 1500 participants who received a dose of mRNA-1345 in Part A Phase 3 will be randomly assigned in a 2:1 randomization ratio to receive a single BD injection of either mRNA-1345 at the selected dose or placebo.

Study Timeline

• Study First Submitted: 2021-11-09
• Study First Submitted QC: 2021-11-09
• Study Start: 2021-11-17
• Study First Posted: 2021-11-19
• Status Verified: 2025-06
• Last Update Submitted: 2025-06-04
• Last Update Posted: 2025-06-05
• Primary Completion: 2025-08-25
• Study Completion: 2025-08-25

Recruitment & Eligibility

• Status: ACTIVE_NOT_RECRUITING
• Sex: All
• Target Recruitment: 36814

Inclusion Criteria

Not provided

Exclusion Criteria

Not provided

Study & Design

• Study Type: INTERVENTIONAL
• Study Design: PARALLEL

Arm && Interventions

Group	Intervention	Description
Placebo	Placebo	Single injection of mRNA-1345 matching-placebo on Day 1.
mRNA-1345	mRNA-1345	Single injection of mRNA-1345 on Day 1.
mRNA-1345 BD	mRNA-1345	Single injection of mRNA-1345 on BD Day 1.

Primary Outcome Measures

Name	Time	Method
Number of Participants with Solicited Local and Systemic Adverse Reactions (ARs)	Up to 7 days after each injection
Number of Participants with Unsolicited Adverse Events (AEs)	Up to 28 days after each injection
Vaccine Efficacy (VE) of mRNA-1345 to Prevent a First Episode of RSV-LRTD with 2 or More Symptoms	From 14 days postinjection up to 12 months postinjection	VE of mRNA-1345 to prevent reverse transcription polymerase chain reaction (RT-PCR) confirmed protocol-defined RSV-LRTD, defined as 100\*(1-HR ratio), where HR is the hazard ratio (mRNA-1345 versus placebo).
Geometric Mean Titer (GMT) of Serum Respiratory Syncytial Virus Subtype A (RSV-A) and Respiratory Syncytial Virus Subtype B (RSV-B) Neutralizing Antibodies	BD Day 29
Number of Participants With Medically Attended AEs (MAAEs), Adverse Events of Special Interests (AESIs), Serious Adverse Events (SAEs), and AEs Leading to Withdrawal	Up to BD Day 181
VE of mRNA-1345 to Prevent a First Episode of RSV-LRTD with 3 or More Symptoms	From 14 days postinjection up to 12 months postinjection	VE of mRNA-1345 to prevent reverse transcription polymerase chain reaction (RT-PCR) confirmed protocol-defined RSV-LRTD, defined as 100\*(1-HR ratio), where HR is the hazard ratio (mRNA-1345 versus placebo).
Geometric Mean Ratio (GMR) of Serum RSV-A and RSV-B Neutralizing Antibodies After BD Compared to After Initial Dose	BD Day 29

Secondary Outcome Measures

Name	Time	Method
GMT of Serum RSV Neutralizing Antibodies	Baseline through up to 24 months postinjection
Geometric Mean Concentration (GMC) of Serum RSV Binding Antibodies	Baseline through up to 24 months postinjection
GMFR of Serum RSV-A and RSV-B Neutralizing Antibodies from Pre-primary Dose (Baseline)	Baseline, BD Day 1, Day 29 and Day 181
VE of mRNA-1345 to Prevent First Hospitalization Associated with RSV-ARD or RSV-LRTD	From 14 days postinjection up to 12 months postinjection	VE of mRNA-1345 to prevent first hospitalization associated with RSV-ARD or RSV-LRTD, defined as 100\*(1-HR ratio), where HR is the hazard ratio (mRNA-1345 versus placebo).
Proportion of Participants with ≥4-fold Increases in Antibody Titers from Baseline	Baseline through up to 24 months postinjection
Seroresponse Rate (SRR) Difference Between Serum RSV-A and RSV-B Neutralizing Antibodies After BD Compared to After Initial Dose	BD Day 29
GMT of Serum RSV-A and RSV-B Neutralizing Antibodies	BD Day 1 and Day 181
VE of mRNA-1345 to Prevent a First Episode of RSV-Associated Acute Respiratory Disease (RSV-ARD)	From 14 days postinjection up to 12 months postinjection	VE of mRNA-1345 to prevent RT-PCR confirmed protocol-defined RSV-ARD, defined as 100\*(1-HR ratio), where HR is the hazard ratio (mRNA-1345 versus placebo).
Seroresponse Rate in RSV Neutralizing Antibodies	Baseline through up to 24 months postinjection
Geometric Mean Fold-Rise (GMFR) of Postbaseline/Baseline Antibody Titers	Baseline through up to 24 months postinjection
SRR of Serum RSV-A and RSV-B Neutralizing Antibodies from Pre-primary Dose (Baseline)	Baseline, BD Day 1, Day 29 and Day 181

Trial Locations

Locations (266)

AES - DRS - Synexus Clinical Research US, Inc. - Birmingham; 🇺🇸 Birmingham, Alabama, United States

Accel Research Site - Achieve - Birmingham; 🇺🇸 Birmingham, Alabama, United States

Lakeview Clinical Research; 🇺🇸 Guntersville, Alabama, United States

AES - DRS - Optimal Research Alabama - Huntsville; 🇺🇸 Huntsville, Alabama, United States

Hope Research Institute LLC - Hunt - PPDS; 🇺🇸 Hunt, Arizona, United States

Desert Clinical Research, LLC - CCT; 🇺🇸 Mesa, Arizona, United States

Hope Research Institute LLC - Phoenix - Hunt - PPDS; 🇺🇸 Phoenix, Arizona, United States

AES - DRS - Synexus Clinical Research US, Inc. - Phoenix Central; 🇺🇸 Phoenix, Arizona, United States

Synexus Clinical Research US, Inc. - Phoenix Southeast; 🇺🇸 Phoenix, Arizona, United States

Tucson Neuroscience Research - M3 WR; 🇺🇸 Tucson, Arizona, United States

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