A Study of mRNA-1345 Vaccine Targeting Respiratory Syncytial Virus in Pregnant Women and in Infants Born to Vaccinated Mothers

Phase 2

Active, not recruiting

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

• Registration Number: NCT06143046
• Lead Sponsor: ModernaTX, Inc.

Brief Summary

The purpose of the study is to evaluate the reactogenicity, safety, and immunogenicity of an investigational respiratory syncytial virus (RSV) vaccine, mRNA-1345, in pregnant women, and safety and immunogenicity in infants born to vaccinated mothers.

Detailed Description

Not available

Study Timeline

• Study First Submitted: 2023-11-14
• Study Start: 2023-11-15
• Study First Submitted QC: 2023-11-19
• Study First Posted: 2023-11-22
• Status Verified: 2025-03
• Last Update Submitted: 2025-03-12
• Last Update Posted: 2025-03-13
• Primary Completion: 2026-02-18
• Study Completion: 2026-02-18

Recruitment & Eligibility

• Status: ACTIVE_NOT_RECRUITING
• Sex: All
• Target Recruitment: 360

Inclusion Criteria

Maternal Participants

• Are adults ≥18 years to <40 years of age inclusive, at the time of signing the informed consent.
• Will be 28 to 36 weeks pregnant at the time of vaccination (confirmed by an obstetric ultrasound report).
• Intend to deliver at a maternity unit where study procedures can be performed.
• Are willing and able to attend all study visits, to undergo all study procedures/or have their infant undergo all study procedures, and to comply with study requirements, including a means of communication (for example, phone, text message or email) with study site staff.
• Have engaged with local antenatal care and will continue to do so through the remainder of their pregnancy.
• Have had an antenatal obstetric ultrasound at ≥18 weeks of pregnancy or be willing to have an antenatal obstetric ultrasound at Screening if not already conducted.

Specific inclusion criteria for Japanese pregnant women:

• Japanese participants are defined as individuals born in Japan, with both parents and 4 grandparents who were born in Japan.

Infant Participants

• Have consent from infant participant's parent(s)/legally authorized representative (LAR) if required by local regulations.

Key

Exclusion Criteria

Maternal Participants

• Acutely ill or febrile (temperature ≥38.0 degrees Celsius [℃]/100.4 degrees Fahrenheit [°F]) within 72 hours prior to or at the Screening Visit or Day 1.
• Reported history of anaphylaxis or severe hypersensitivity reaction after receipt of any mRNA vaccine or therapeutic or any components of an mRNA-1345 vaccine.
• Any medical, psychiatric, or occupational condition, including reported history of drug or alcohol abuse, that, in the opinion of the Investigator, might pose additional risk due to participation in the study or could interfere with the interpretation of study results.
• Have conditions in the current pregnancy or in previous pregnancies that may affect participant safety, assessment of safety endpoints, assessment of immune response, or adherence to study procedures.
• Received or plans to receive any mRNA vaccine or COVID-19 vaccine within 4 weeks before or after Day 1 and/or any other nonstudy vaccine within 2 weeks before or after Day 1.
• Previous vaccination with any licensed or investigational RSV vaccine or planned receipt during study participation.
• Intend for their infant to receive RSV monoclonal antibodies after delivery.

Infant Participants

• Is a child who has been placed under the control or protection of an agency, organization, institution, or entity by the courts, the government, or a government body acting in accordance with powers conferred on them by laws and regulation (for example, foster care). This does not include a child who is adopted or has an appointed LAR.

Other inclusion and exclusion criteria may apply.

Study & Design

• Study Type: INTERVENTIONAL
• Study Design: PARALLEL

Arm && Interventions

Group	Intervention	Description
mRNA-1345 Dose B	mRNA-1345	Participants will be vaccinated in the period from 28 weeks to 36 weeks of gestation with a single IM injection of mRNA-1345 Dose B.
mRNA-1345 Dose C	mRNA-1345	Participants will be vaccinated in the period from 28 weeks to 36 weeks of gestation with a single IM injection of mRNA-1345 Dose C.
Placebo	Placebo	Participants will receive single IM injection of mRNA-1345 vaccine matching placebo in the period from 28 weeks to 36 weeks of gestation.
mRNA-1345 Dose A	mRNA-1345	Participants will be vaccinated in the period from 28 weeks to 36 weeks of gestation with a single intramuscular (IM) injection of mRNA-1345 Dose A.

Primary Outcome Measures

Name	Time	Method
Number of Maternal Participants with Adverse Events of Special Interest (AESIs)	Day 1 to Month 12 (12 months postdelivery)
Number of Maternal Participants with Serious Adverse Events (SAEs)	Day 1 to Month 12 (12 months postdelivery)
Number of Infant Participants with MAAEs	Day 1 (birth) to Month 12
Number of Maternal Participants with Solicited Local and Systemic Adverse Reactions (ARs)	Up to Day 7 (7 days post vaccination)
Number of Infant Participants with AESIs	Day 1 (birth) to Month 12
Number of Infant Participants with SAEs	Day 1 (birth) to Month 12
Number of Maternal Participants with Unsolicited Adverse Events (AEs)	Up to Day 28 (28 days post vaccination)
Number of Maternal Participants with Medically-Attended AEs (MAAEs)	Day 1 to Month 6 (6 months postdelivery)
Number of Maternal Participants with AEs Leading to Discontinuation	Day 1 to Month 12 (12 months postdelivery)
Number of Maternal Participants With Pregnancy Outcomes	Day 1 to Month 12 (12 months postdelivery)	Pregnancy outcomes will include stillbirth, live birth, vaginal delivery, and cesarean section delivery.
Number of Infant Participants With Birth Outcomes	Day 1 (birth) to Month 12	Birth outcomes will include gestational age and anthropometric measurements.

Secondary Outcome Measures

Name	Time	Method
Geometric Mean Titer (GMT) of Serum RSV-A and RSV-B Neutralizing Antibodies in Maternal Participants	Day 1, Day 29, delivery, and Month 6 (6 months postdelivery)
GMT of Serum RSV-A and RSV-B Neutralizing Antibodies in Infant Participants	Day 1 (birth), and Months 2, 6, and 12
GMC of Serum RSV-F Binding Antibodies in Infant Participants	Day 1 (birth), and Months 2, 6, and 12
Geometric Mean Fold-Rise (GMFR) of Postbaseline/Baseline Neutralizing Antibody Titers and Binding Antibody Concentrations in Maternal Participants	Day 29, delivery, and Month 6 (6 months postdelivery)
Percentage of Maternal Participants With ≥4-fold Increase From Baseline in Neutralizing Antibody Titers and Binding Antibody Concentrations	Baseline up to Month 6 (6 months postdelivery)
Geometric Mean Concentration (GMC) of Serum RSV-F Binding Antibodies in Maternal Participants	Day 1, Day 29, delivery, and Month 6 (6 months postdelivery)

Trial Locations

Locations (56)

SEC Clinical Research LLC - Dothan 2 - ClinEdge - PPDS; 🇺🇸 Dothan, Alabama, United States

Abby's Research Institute; 🇺🇸 Phoenix, Arizona, United States

Watching Over Mothers & Babies; 🇺🇸 Tucson, Arizona, United States

Applied Research Center of Arkansas - ClinEdge - PPDS; 🇺🇸 Little Rock, Arkansas, United States

Matrix Clinical Research - Gardena; 🇺🇸 Gardena, California, United States

Matrix Clinical Research - Huntington Park; 🇺🇸 Huntington Park, California, United States

Matrix Clinical Research, Inc - Corporate Office; 🇺🇸 Los Angeles, California, United States

Clinical Research Prime - ClinEdge - PPDS; 🇺🇸 Idaho Falls, Idaho, United States

Bingham Memorial Hospital; 🇺🇸 Pocatello, Idaho, United States

Clinical Research Prime - ClinEdge - Rexburg - PPDS; 🇺🇸 Rexburg, Idaho, United States

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