NCT04975893

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

A Phase 2, Non-Randomized, Long-Term Extension Study to Evaluate the Immunogenicity and Safety of Cytomegalovirus mRNA-1647 Vaccine Including a Booster Dose in a Subset of Participants Who Completed Study mRNA-1647-P202

• Status: Completed
• Phase: Phase 2
• Study type: Interventional
• Enrollment: 135 (actual)
• Sponsor: ModernaTX, Inc. · Industry
• Sex: All
• Age: 18 Years – 40 Years
• Healthy volunteers: Not accepted

Summary

The main purpose of the extension phase 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). For participants in the optional booster phase (BP), the main purpose is to evaluate the long-term immunogenicity and safety of the mRNA-1647 vaccine in both participants receiving a booster dose (BD) and those not receiving a BD, and to additionally evaluate the reactogenicity in participants receiving a BD.

Detailed description

The study aims to explore the long-term potential differences in immunogenicity and key safety parameters following mRNA-1647 administration, participants who completed study mRNA-1647-P202, 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 the primary extension phase of this study. Eligible participants enrolling in the primary extension phase 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. In the optional BP, consenting and eligible participants will receive a single BD of the mRNA-1647 vaccine (medium dose). In the Observational Group of the optional BP, consenting and eligible participants will not receive study treatment.

Conditions

• Cytomegalovirus Infection

Interventions

Type	Name	Description
BIOLOGICAL	mRNA-1647	No investigational product will be administered during the Primary Extension Phase or to the participants in the Observational Group.
OTHER	mRNA-1647	Lyophilized product that is reconstituted with saline then diluted with a special diluent to reach the desired concentration

Timeline

• Start date: 2021-06-18
• Primary completion: 2026-01-19
• Completion: 2026-01-19
• First posted: 2021-07-26
• Last updated: 2026-02-02

Locations

7 sites across 1 country: United States

Regulatory

• FDA-regulated drug study