A Phase 2, Randomized, Observer-blind Study to Evaluate the Safety, Reactogenicity, and Immunogenicity of mRNA-1345, an mRNA Vaccine Targeting Respiratory Syncytial Virus, in Children 2 to <18 Years of Age at High Risk of Respiratory Syncytial Virus Disease

mRNA-1345-P202

The purpose of the study is to evaluate the safety, reactogenicity, and immunogenicity of mRNA-1345 in children aged 2 to \<5 years of age and in children at high risk of respiratory syncytial virus (RSV) disease 5 to \<18 years of age to inform the dose level selection for the next phase of development (Phase 3).

2023-10-24

2024-07-19

2024-07-19

Active (not recruiting)

Early phase I

340

Key Inclusion Criteria: Cohort 1: * 2 to \<5 years of age, at the time the informed consent is signed. * Healthy, or with stable chronic conditions increasing the risk of RSV disease, per the clinical judgment of the Investigator. Cohort 2: * 5 to \<18 years of age, at the time the informed consent is signed. * Participants with stable chronic conditions increasing the risk of RSV disease. * Female participants of child-bearing potential may be enrolled in the study, if the participant: 1) has a negative urine pregnancy test at Screening and on the day of injection (Day 1); 2) has practiced adequate contraception or has abstained from all activities that could lead to pregnancy for 28 days prior to Day 1; 3) has agreed to continue adequate contraception through 90 days following injection; and 4) is not currently breastfeeding. Key Exclusion Criteria: * Acutely ill or febrile (temperature ≥38.0°Celsius \[100.4°Fahrenheit\]) within 72 hours prior to or at the Screening Visit or Day 1. * History of a diagnosis or condition that, in the judgment of the Investigator, may affect study assessment or compromise participant safety. * Has received or plans to receive any licensed or authorized vaccine ≤14 days prior to the study vaccine injection (Day 1) or plans to receive a licensed or authorized vaccine within 14 days after the study vaccine injection. * Receipt of any prior systemic immunosuppressants or immune-modifying drugs. Short courses (\<7 days) of oral corticosteroids are allowed if completed at least 3 months prior to enrollment. * Receipt of RSV monoclonal antibodies within 6 months prior to enrollment in the study. * Participated in an interventional clinical study within 28 days (6 months for a study assessing a product unlicensed in this age group) prior to the day of enrollment or plans to do so while enrolled in this study. Note: Other protocol-defined inclusion and exclusion criteria may apply.

{'studyType': 'INTERVENTIONAL', 'phases': ['PHASE2'], 'designInfo': {'allocation': 'RANDOMIZED', 'interventionModel': 'PARALLEL', 'primaryPurpose': 'PREVENTION', 'maskingInfo': {'masking': 'QUADRUPLE', 'whoMasked': ['PARTICIPANT', 'CARE_PROVIDER', 'INVESTIGATOR', 'OUTCOMES_ASSESSOR']}}, 'enrollmentInfo': {'count': 340, 'type': 'ESTIMATED'}}

2024-02-26