A Long-Term Extension Study to Evaluate the Immunogenicity and Safety of Cytomegalovirus (CMV) mRNA-1647 Vaccine

Study Overview
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Brief Summary
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The main purpose of this study is to evaluate the longer-term immune persistence of mRNA-1647 vaccine administered to CMV-seronegative and CMV-seropositive adults who completed Study mRNA-1647-P202 (NCT04232280).

Detailed Description
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The study aims to explore the long-term potential differences in immunogenicity and key safety parameters following mRNA-1647 administration in CMV-seronegative and CMV-seropositive participants. Study mRNA-1647-P202 participants who are CMV-seronegative and who did not seroconvert due to primary CMV infection during the study will be enrolled. Study mRNA-1647-P202 participants who were CMV-seropositive at baseline, randomized to receive mRNA-1647 injection, and completed their final study visit will also be enrolled. No study treatment will be administered during this extension study. Eligible participants enrolling in the extension study who completed Study mRNA-1647-P202 may have received mRNA-1647 (either low dose, medium dose, or high dose) or placebo in CMV-seronegative participants and mRNA-1647 (either low dose, medium dose, or high dose) in CMV-seropositive participants.

Official Title
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A Phase 2, Non-Randomized, Long-Term Extension Study to Evaluate the Immunogenicity and Safety of Cytomegalovirus mRNA-1647 Vaccine in Participants Who Completed Study mRNA-1647-P202

Conditions
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Cytomegalovirus Infection

Intervention / Treatment
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* Biological: mRNA-1647


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: Male or female participants who were CMV-seronegative at the Study mRNA-1647-P202 Screening visit, completed the final Study mRNA-1647-P202 visit, and remained CMV-seronegative at Screening for Study mRNA-1647-P202-EXT. Male and female participants who were CMV-seropositive at the Study mRNA-1647-P202 Screening visit, were randomized to receive mRNA-1647 injection (and not placebo), and completed the final visit in Study mRNA-1647-P202. Understands and agrees to comply with the trial procedures and provides written informed consent. According to the assessment of the Investigator, is in good general health and is capable of complying with trial procedures. Exclusion Criteria: Receipt of any CMV vaccine other than mRNA-1647. Diagnosis or condition that, in the judgment of the Investigator, may affect participant safety, assessment of safety endpoints, assessment of immune response, or adherence to trial procedures, including any medical, psychiatric, or occupational condition 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.

Ages Eligible for Study
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Minimum Age: 18 Years
Maximum Age: 40 Years

Sexes Eligible for Study
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All

Accepts Healthy Volunteers
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No

Study Plan
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How is the study designed?
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Design Details

Primary Purpose: Prevention
Intervention Model: Single Group Assignment
Masking: None (Open Label)


Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Other: CMV-seropositive and CMV-seronegative Participants<br>CMV-seropositive and CMV-seronegative participants who completed Study mRNA-1647-P202 will be followed every 6 months for 3 years in this study after the final visit in Study mRNA-1647-P202. | Biological: mRNA-1647<br>* No investigational product will be administered in this extension study.<br>|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Geometric Mean Titers (GMTs) of Antigen-Specific Neutralizing Antibody (nAb) and Binding Antibody (bAb) |  | Up to 3 years | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Number of Participants With Adverse Events (AEs) Leading to Study Discontinuation |  | Up to 3 years | 
| Number of Participants With Serious Adverse Events (SAEs) |  | Up to 3 years | 
| Number of Participants who Died |  | Up to 3 years | 

 Terms related to the study
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Keywords Provided by Centre Hospitalier Valida
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CMV, Moderna, mRNA-1647, Cytomegalovirus, Cytomegalovirus Vaccine, Cytomegalovirus Infections, Cytomegalovirus Congenital, Virus Diseases, Infection Viral, DNA Virus Infections, Messenger RNA