A Safety, Tolerability, and Immunogenicity Study of mRNA-1345 and mRNA-1365 in Participants Aged 5 Months to <24 Months

Running, not enrolling · Phase 1 · Has a placebo group

Conditions studied: Respiratory Syncytial Virus, Human Metapneumovirus

In brief

The purpose of this study is to assess the safety and immunogenicity of mRNA-1365, an mRNA vaccine targeting respiratory syncytial virus (RSV) and human metapneumovirus (hMPV) and mRNA-1345, an mRNA vaccine targeting RSV, in participants aged 5 months to \<24 months.

Key facts

Study ID

NCT05743881

Run by

ModernaTX, Inc.

People needed

186

Starts

2023-02-15

Expected to finish

2029-08-31

Last updated by the study team

2026-06-26

Who can join

Age: 0 and older, up to 2. Sex: any. Healthy volunteers: not accepted.

You may qualify if…

• The participant is 8 months to <24 months (Part A), 5 months to <8 months (Part B), or 8 months to <12 months (Part C) of age at the time of randomization (Day 1/Baseline visit), who is in good general health, in the opinion of the Investigator, based on review of medical history and screening physical examination.
• In the Investigator's opinion, the parent(s)/ legally authorized representative (LAR)(s) understand and are willing and physically able to comply with protocol-mandated follow up, including all procedures, and provide written informed consent.
• The participant is growing normally for age in the opinion of the site clinician in the months prior to enrollment.
• The participant was born at full-term (≥37 weeks gestation) with a minimum birth weight of 2.5 kilograms (kg).
• For Part C Cohort 7: participant must have received nirsevimab ≥6 months prior to Day 1 Visit.
• For Part C Cohort 8: participant was eligible at any time since birth, according to national guidelines, to receive nirsevimab prior to Day 1 Visit but did not do so.

You may not qualify if…

• Has a known history of symptomatic RSV (Part A: within 3 months; Part B and Part C: since birth) or hMPV infection (Part A: within 3 months; Part B: since birth) prior to administration of the first dose of investigational product (IP) or has a known close contact with anyone with laboratory-confirmed RSV (Parts A, B, and C) or hMPV infection (Parts A or B) within 14 days prior to administration of the first dose of IP.
• Is acutely ill or febrile 24 hours prior to or at the screening visit. Fever is defined as a body temperature ≥38.0°Celsius/≥100.4°Fahrenheit. Participants who meet this criterion may have visits rescheduled within the relevant study visit windows.
• Has previously been administered an investigational or approved vaccine for prevention of RSV (Parts A, B, and C) or hMPV (Parts A and B) infection or if the participant's mother received an investigational or approved vaccine for the prevention of RSV (Parts A, B, and C) or hMPV (Parts A and B) infection during pregnancy.
• Has received investigational or approved agents for prophylaxis against RSV or hMPV (for example, monoclonal antibodies) or is intending to receive these during the course of the study. For Part C (Cohort 7 only), use of nirsevimab ≥6 months before Day 1 Visit is allowed.
• Has a known hypersensitivity to a component of the vaccine or its excipients. Hypersensitivity includes, but is not limited to, anaphylaxis or immediate allergic reaction of any severity to a previous dose of an mRNA vaccine or any of its components (including polyethylene glycol or immediate allergic reaction of any severity to polysorbate).
• Has a medical condition that, according to the Investigator's judgment, may pose additional risk as a result of participation, interfere with safety assessments, or interfere with interpretation of results.
• Note: Other protocol-defined inclusion/exclusion criteria apply.
• Inclusion Criteria:
• For Part B Extension: participants enrolled and dosed in Part B (Cohorts 3 to 6); either reached the end of study of the Main Study or were dosed and subsequently discontinued from the Main Study. This includes participants who were lost to follow-up, if they can be re-engaged.
• For Part B Extension: participant's parent(s)/LAR(s) has provided written informed consent for participation in Part B of the Main Study and the Part B Extension.
• Exclusion Criteria:
• For Part B Extension, there are no specific exclusion criteria.

Where it is running

• Matrix Clinical Research — Los Angeles, California, United States
• Meridian Clinical Research — Washington D.C., District of Columbia, United States
• DM Clinical Research- River Forest — Melrose Park, Illinois, United States
• MedPharmics - Platinum - PPDS — Lafayette, Louisiana, United States
• Duke Vaccine and Trials Unit — Durham, North Carolina, United States
• Velocity Clinical Research - Providence — Providence, Rhode Island, United States
• Palmetto Pediatrics, PA — North Charleston, South Carolina, United States
• Vanderbilt Vaccine Research Program — Nashville, Tennessee, United States
• CyFair — Houston, Texas, United States
• Pediatric Associates — Houston, Texas, United States
• Village Pediatrics — Plano, Texas, United States
• Pediatric Center — Richmond, Texas, United States
• CEVAXIN David — David, Chiriquí Province, Panama
• CEVAXIN Chorrera — La Chorrera, Panamá Oeste Province, Panama
• CEVAXIN Avenida Mexico — Panama City, Panama
• CEVAXIN 24 de Diciembre — Panama City, Panama
• Norfolk and Norwich University Hospitals — Norwich, United Kingdom

Full record on ClinicalTrials.gov

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