NCT05085366

A Study to Evaluate the Efficacy, Safety, and Immunogenicity of mRNA-1647 Cytomegalovirus (CMV) Vaccine in Healthy Participants 16 to 40 Years of Age

A Phase 3, Randomized, Observer-Blind, Placebo-Controlled Study to Evaluate the Efficacy, Safety, and Immunogenicity of mRNA-1647 Cytomegalovirus (CMV) Vaccine in Healthy Participants 16 to 40 Years of Age

• Status: Terminated
• Phase: Phase 3
• Study type: Interventional
• Enrollment: 7,454 (actual)
• Sponsor: ModernaTX, Inc. · Industry
• Sex: Female
• Age: 16 Years – 40 Years
• Healthy volunteers: Accepted

Summary

The main purpose of this study is to evaluate the efficacy of mRNA 1647 vaccine in CMV-seronegative female participants and to evaluate the safety and reactogenicity of mRNA-1647 vaccine in all participants. The purpose of the Phase 3 extension substudy is to extend the observation period of the main study and to assess the longer-term immunogenicity, efficacy, and safety of the mRNA-1647 vaccine against primary CMV infection in healthy females who were CMV-seronegative at Baseline of the mRNA-1647-P301 main study (including participants who remain CMV-seronegative upon entry into the extension substudy and participants who seroconverted during the main study). The extension substudy will also evaluate the immune persistence and safety of mRNA-1647 in a subset of female participants who were CMV-seropositive at Baseline of the main study. No interventional vaccine will be administered in the extension substudy.

Conditions

• Cytomegalovirus Infection

Interventions

Type	Name	Description
BIOLOGICAL	mRNA-1647	Lyophilized product that is reconstituted with 0.9% sodium chloride (normal saline)
BIOLOGICAL	Placebo	0.9% sodium chloride (normal saline) injection

Timeline

• Start date: 2021-10-26
• Primary completion: 2025-11-04
• Completion: 2025-11-04
• First posted: 2021-10-20
• Last updated: 2025-12-15

Locations

296 sites across 13 countries: United States, Australia, Belgium, Canada, Estonia, Finland, France, Germany, Israel, Italy, Japan, Spain, United Kingdom

Regulatory

• FDA-regulated drug study