A Study of mRNA-1647 Cytomegalovirus Vaccine in Healthy Participants 9 to 15 Years of Age and Participants 16 to 25 Years of Age

A Phase 1/2a Open-Label Dose-Ranging and Observer-Blind Placebo-Controlled, Safety and Immunogenicity Study of mRNA-1647 Cytomegalovirus Vaccine in Female and Male Participants 9 to 15 Years of Age and Participants 16 to 25 Years of Age

The main purpose of study is to evaluate the safety and immunogenicity of different dose levels of mRNA-1647 versus control in healthy cytomegalovirus (CMV)-seronegative and CMV-seropositive female and male participants 9 to 15 years of age. In addition, mRNA-1647 will be evaluated in female participants 16 to 25 years as a comparator cohort.

Study Overview

• Status: Completed
• Conditions: Cytomegalovirus
• Intervention / Treatment: Biological: mRNA-1647; Other: Placebo

Detailed Description

The study will be conducted in 2 parts: Part 1 Dose-Ranging and Part 2 Safety Expansion.

• Study Type: Interventional
• Enrollment (Actual): 873
• Phase: Phase 2; Phase 1

Contacts and Locations

Study Locations

• Canada
  • Alberta
    • Calgary, Alberta, Canada
      • M.A.G.I.C. Clinic Ltd. Metabolics and Genetics in Calgary
    • Edmonton, Alberta, Canada
      • ALTA Clinical Research Inc
    • Red Deer, Alberta, Canada
      • CARe Clinic
  • Nova Scotia
    • Halifax, Nova Scotia, Canada
      • Canadian Center for Vaccinology
  • Ontario
    • Hamilton, Ontario, Canada
      • Hamilton Medical Research Group
    • Sarnia, Ontario, Canada
      • Bluewater Clinical Research Group
  • Quebec
    • Montreal, Quebec, Canada
      • Centre Hospitalier Universitaire Sainte-Justine
• United Kingdom
  • Birmingham, United Kingdom
    • Queen Elizabeth Hospital
  • Cardiff, United Kingdom
    • Noah's Ark Children's Hospital for Wales
  • London, United Kingdom
    • St. George Hospital
  • Hampshire
    • Southampton, Hampshire, United Kingdom
      • Southampton General Hospital
  • Northamptonshire
    • Corby, Northamptonshire, United Kingdom
      • Lakeside Healthcare
  • South Yorkshire
    • Sheffield, South Yorkshire, United Kingdom
      • Sheffield Children's Hospital
• United States
  • California
    • La Mesa, California, United States, 91942-3189
      • Paradigm Clinical Research Institute Inc - ClinEdge - PPDS
    • La Mesa, California, United States, 91942
      • Velocity Clinical Research - San Diego - PPDS
    • Sacramento, California, United States, 95864
      • Benchmark Research - Sacramento -Hypercore- PPDS
  • Colorado
    • Fort Collins, Colorado, United States, 80525-5752
      • Tekton Research - Fort Collins - Platinum - PPDS
  • District of Columbia
    • Washington D.C., District of Columbia, United States, 20016
      • Velocity Clinical Research (Washington)- PPDS
  • Florida
    • Doral, Florida, United States, 33166-6613
      • Prohealth Research Center
    • Jacksonville, Florida, United States, 32209
      • University of Florida Jacksonville
    • Orlando, Florida, United States, 32801-2987
      • Clinical Neurosciences Solutions Inc. (Orlando-East South St)
    • Tampa, Florida, United States, 33609-2230
      • Palm Harbor Dermatology
    • Tampa, Florida, United States, 33615-3219
      • Santos Research Center
  • Georgia
    • Atlanta, Georgia, United States, 30322-1014
      • Children's Healthcare of Atlanta
    • Decatur, Georgia, United States, 30030-3438
      • iResearch Atlanta - CenExel - PPDS
  • Idaho
    • Idaho Falls, Idaho, United States, 83404-5305
      • Clinical Research Prime - ClinEdge - PPDS
  • Louisiana
    • Covington, Louisiana, United States, 70433
      • Benchmark Research - Covington - HyperCore- PPDS
    • New Orleans, Louisiana, United States, 70112-2632
      • Tulane Medical Center
  • Maryland
    • Baltimore, Maryland, United States, 21201-1509
      • University of Maryland School of Medicine
    • Columbia, Maryland, United States, 21045
      • The Pediatric Centre
    • Frederick, Maryland, United States, 21702
      • The Pediatric Centre of Frederick
  • Michigan
    • Detroit, Michigan, United States, 48201
      • Wayne State University
  • Minnesota
    • Minneapolis, Minnesota, United States, 55455
      • University of Minnesota
  • Mississippi
    • Gulfport, Mississippi, United States, 39503
      • Velocity Clinical Research - Gulfport
  • Nebraska
    • Lincoln, Nebraska, United States, 68510
      • Velocity Clinical Research (Lincoln-Nebraska) - PPDS
    • Norfolk, Nebraska, United States, 68701-7701
      • Velocity Clinical Research (Norfolk - Nebraska) - PPDS
    • Omaha, Nebraska, United States, 68134-3664
      • Velocity Clinical Research (Omaha-Nebraska) - Platinum - PPDS
  • New Mexico
    • Albuquerque, New Mexico, United States, 87102-2619
      • Albuquerque Clinical Trials Inc - Clinedge - PPDS
    • Albuquerque, New Mexico, United States, 87102-3644
      • Velocity Clinical Research -Albuquerque -PPDS
  • New York
    • Binghamton, New York, United States, 13901-1046
      • Velocity Clinical Research (Binghamton - New York) - PPDS
    • Rochester, New York, United States, 14609-3173
      • Rochester Clinical Research, Inc
  • North Carolina
    • Charlotte, North Carolina, United States, 28277-4859
      • OnSite Clinical Solutions, LLC - ClinEdge - PPDS
  • Oklahoma
    • Edmond, Oklahoma, United States, 73013
      • Tekton Research - Oklahoma- PPDS
    • Norman, Oklahoma, United States, 73072-3251
      • Lynn Institute of Norman - ERN - PPDS
  • Oregon
    • Medford, Oregon, United States, 97504-7738
      • Velocity Clinical Research - Medford - PPDS
  • Tennessee
    • Nashville, Tennessee, United States, 37208
      • Meharry Medical College
  • Texas
    • Austin, Texas, United States, 78705
      • Tekton Research - Texas - PPDS
    • Beaumont, Texas, United States, 77706-3061
      • Tekton Research - Beaumont - Platinum - PPDS
    • Fort Worth, Texas, United States, 76135
      • Benchmark Research - Fort Worth - HyperCore -PPDS
    • Galveston, Texas, United States, 77550
      • University of Texas Medical Branch (UTMB)
    • Houston, Texas, United States, 77055-1626
      • West Houston Clinical Research - Hunt - PPDS
    • Port Lavaca, Texas, United States, 77979
      • Victoria Clinical Research Group
    • San Angelo, Texas, United States, 76904
      • Benchmark Research - San Angelo - HyperCore - PPDS
    • San Antonio, Texas, United States, 78229
      • Tekton Research - Texas - Platinum - PPDS
    • Tomball, Texas, United States, 77375
      • DM Clinical Research - ERN- PPDS
    • Victoria, Texas, United States, 77901
      • Crossroads Clinical Research (Victoria)
  • Utah
    • Salt Lake City, Utah, United States, 84107-4536
      • JBR Clinical Research - CenExel JBR - PPDS

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: 9 years to 25 years (Child, Adult)
• Accepts Healthy Volunteers: Yes

Description

Key Inclusion Criteria:

• Is a female or male 9 to 15 years of age or is a female 16 to 25 years of age at the time of consent.
• Is in good general health, in the opinion of the Investigator, and is capable of complying with study procedures.
• For the CMV-seronegative cohorts: At the Screening visit, is CMV IgG-negative and CMV immunoglobulin M (IgM)-negative.
• For the CMV-seropositive cohorts: At the Screening visit, is CMV IgG-positive and CMV IgM-negative, CMV IgG-positive and CMV IgM-positive, or CMV IgG-positive and CMV IgM-indeterminate. Participants with an isolated positive or indeterminate result for CMV IgM (that is, CMV IgG-negative and either CMV IgM-positive or CMV IgM-indeterminate) will not be eligible for enrollment but may be rescreened after at least 6 weeks from the initial CMV Screening. Participants with an indeterminate result for CMV IgG, regardless of IgM result, will not be eligible for enrollment but may be rescreened after at least 6 weeks from the initial CMV screening.
• If 9 to 15 years of age, has a body mass index (BMI) at or above the third percentile according to World Health Organization (WHO) Child Growth Standards. If 16 to 25 years of age: has a BMI of 15 to 35 kilograms (kg)/square meter (m^2).
• For female participants of childbearing potential: negative pregnancy test, adequate contraception or has abstained from all activities that could result in pregnancy for at least 28 days prior to Day 1, agreement to continue adequate contraception through 3 months following vaccine administration.

Key Exclusion Criteria:

• Has a history of a diagnosis or condition that, in the judgment of Investigator, is clinically unstable or may affect participant safety, assessment of safety endpoints, assessment of immune response, or adherence to study procedures. Clinically unstable is defined as diagnosis or condition requiring significant changes in management or medication within the 2 months prior to Screening and includes ongoing workup of an undiagnosed illness that could lead to a new diagnosis or condition.
• Has received, or plans to receive, any nonstudy vaccine < 28 days prior to or after any study injection.
• Has a screening liver function test (aspartate aminotransferase, alanine aminotransferase, total bilirubin) or a screening creatinine result of Toxicity Grade ≥1.
• Has a Screening hematology or coagulation result of Toxicity Grade ≥1.
• Is acutely ill or febrile (body temperature ≥38.0 degrees Celsius [°C]/100.4 degrees Fahrenheit [°F]) at the Screening Visit.
• Has received systemic immunosuppressants or immune-modifying drugs for > 14 days in total within 6 months prior to the day of enrollment (for corticosteroids, ≥1 milligrams (mg)/kg/day or ≥10 mg/day prednisone equivalent).
• Has received an antiviral with activity against CMV (ganciclovir, valganciclovir, foscarnet, cidofovir, letermovir, acyclovir, valacyclovir) <2 weeks prior to the day of the first study injection (Day 1) or plans to do so during the course of the study.
• Reports a history of myocarditis, pericarditis, or myopericarditis.
• Has reported medical history of hepatitis B, hepatitis C, or human immunodeficiency virus (HIV); or a positive screening test for hepatitis B surface antigen (HBsAg), hepatitis C antibodies, or HIV 1 or 2 antibodies.
• Has previously received an investigational CMV vaccine.
• Has received systemic immunoglobulins or blood products <3 months prior to the day of the first study injection (Day 1).
• Has donated ≥ 450 milliliter (mL) of blood products <28 days prior to the day of the first study injection (Day 1).
• Has participated in an interventional clinical study <28 days prior to the day of the first study injection (Day 1) or plans to do so while enrolled in the study.

Note: Other inclusion and exclusion criteria may apply.

Study Plan

How is the study designed?

Design Details

• Primary Purpose: Prevention
• Allocation: Randomized
• Interventional Model: Sequential Assignment
• Masking: Quadruple

Number of Arms

7

Arms and Interventions

Participant Group / Arm	Intervention / Treatment
Experimental: mRNA-1647 Dose B; CMV-seronegative or CMV-seropositive participants 9 to 15 years of age will receive mRNA-1647 at Dose Level B by IM injection given as a 3-injection series on Day 1, Month 2, and Month 6.	Biological: mRNA-1647; Sterile liquid for injection
Experimental: mRNA-1647 Dose C; CMV-seronegative or CMV-seropositive participants 9 to 15 years of age and 16 to 25 years of age will receive mRNA-1647 at Dose Level C by IM injection given as a 3-injection series on Day 1, Month 2, and Month 6.	Biological: mRNA-1647; Sterile liquid for injection
Experimental: mRNA-1647 Dose A; CMV-seronegative or CMV-seropositive participants 9 to 15 years of age will receive mRNA-1647 at Dose Level A by intramuscular (IM) injection given as a 3-injection series on Day 1, Month 2, and Month 6.	Biological: mRNA-1647; Sterile liquid for injection
Experimental: Dose Expansion: mRNA-1647 (3-dose Schedule); CMV-seronegative or CMV-seropositive participants 9 to 15 years of age will receive mRNA-1647 at selected dose level by IM injection given as a 3-injection series on Day 1, Month 2, and Month 6.	Biological: mRNA-1647; Sterile liquid for injection
Experimental: Dose Expansion: mRNA-1647 (2-dose Schedule); CMV-seronegative participants 9 to 15 years of age will receive mRNA-1647 at selected dose level by IM injection given as a 2-injection series on Day 1 and Month 6.	Biological: mRNA-1647; Sterile liquid for injection
Placebo Comparator: Dose Expansion: Placebo (3-dose Schedule); CMV-seronegative or CMV-seropositive participants 9 to 15 years of age will receive placebo by IM injection given as a 3-injection series on Day 1, Month 2, and Month 6.	Other: Placebo; 0.9% sodium chloride injection (normal saline)
Placebo Comparator: Dose Expansion: Placebo (2-dose Schedule); CMV-seronegative participants 9 to 15 years of age will receive placebo by IM injection given as a 2-injection series on Day 1 and Month 6.	Other: Placebo; 0.9% sodium chloride injection (normal saline)

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Number of Medically Attended Adverse Events (MAAEs)		Up to Day 347 (6 months after the last study injection)
Number of Serious Adverse Events (SAEs), Adverse Events of Special Interest (AESIs), and AEs Leading to Discontinuation		Up to Day 527 (end of study)
Geometric Mean Titer (GMT) of Anti-CMV Neutralizing Antibodies (nAbs)	Serum functional antibody levels against vaccine antigens will be measured by nAb titer against epithelial cell infection and nAb titer against fibroblast infection.	Up to Day 527 (end of study)
Number of Participants with ≥2-Fold, 3-Fold, and 4-Fold increases Over Baseline of Anti-CMV Antibodies	Serum functional antibody levels against vaccine antigens will be measured by nAb titer against epithelial cell infection and nAb titer against fibroblast infection.	Up to Day 527 (end of study)
Number of Solicited Local and Systemic Reactogenicity Adverse Reactions (ARs)		Up to Day 176 (7 days after each study injection)
Number of Unsolicited Adverse Events (AEs)		Up to Day 197 (28 days after each study injection)
Geometric Mean Fold-Rise (GMFR) of Anti-CMV nAbs	Serum functional antibody levels against vaccine antigens will be measured by nAb titer against epithelial cell infection and nAb titer against fibroblast infection.	Up to Day 527 (end of study)

Secondary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Number of Participants with ≥2-Fold, 3-Fold, and 4-Fold Increases Over Baseline of Binding Anti-gB and Anti-pentamer Specific IgG	Serum antigen-specific binding antibody titers against vaccine antigens will be measured by ELISA specific to the gB and pentamer proteins.	Up to Day 527 (end of study)
Geometric Mean Concentration (GMC) of Binding Anti-Glycoprotein B (gB) Specific Immunoglobulin G (IgG) and Anti-Pentamer Specific IgG	Serum antigen-specific binding antibody titers against vaccine antigens will be measured by enzyme-linked immunosorbent assay (ELISA) specific to the gB and pentamer proteins.	Up to Day 527 (end of study)
GMFR of Binding Anti-gB and Anti-pentamer Specific IgG	Serum antigen-specific binding antibody concentrations against vaccine antigens will be measured by ELISA specific to the gB and pentamer proteins.	Up to Day 527 (end of study)

Collaborators and Investigators

• Sponsor: ModernaTX, Inc.

Study record dates

Study Major Dates

• Study Start (Actual): November 7, 2022
• Primary Completion (Actual): May 12, 2026
• Study Completion (Actual): May 12, 2026

Study Registration Dates

• First Submitted: October 7, 2022
• First Submitted That Met QC Criteria: October 7, 2022
• First Posted (Actual): October 12, 2022

Study Record Updates

• Last Update Posted (Actual): June 4, 2026
• Last Update Submitted That Met QC Criteria: June 2, 2026
• Last Verified: May 1, 2026

More Information

Terms related to this study

• Keywords: Moderna; CMV; mRNA-1647 Vaccine
• Additional Relevant MeSH Terms: mRNA-1647 cytomegalovirus vaccine
• Other Study ID Numbers: mRNA-1647-P104; 2022-001545-20 (EudraCT Number)

Drug and device information, study documents

• Studies a U.S. FDA-regulated drug product: Yes
• Studies a U.S. FDA-regulated device product: No