Active — Not RecruitingPhase 2

A Study to Evaluate the Efficacy, Safety, and Immunogenicity of mRNA-1647 Cytomegalovirus (CMV) Vaccine in Allogenic Hematopoietic Cell Transplantation (HCT) Participants.

United States84 participantsStarted 2023-04-05

Plain-language summary

The main purpose of the study is to evaluate the efficacy and safety of mRNA-1647 compared to placebo to prevent first clinically significant cytomegalovirus infection (CS-CMVi) in the period following cessation of CMV prophylactic treatment (for example, letermovir) on Day 100 post-HCT through Month 9 post-HCT.

Who can participate

Age range

18 Years

Sex

ALL

See this in plain English?

AI-rewrites the medical criteria so a patient or caregiver can understand them. Always confirm with the trial site.

Inclusion Criteria: * Receipt of an allogeneic HCT. * CMV-seropositive, defined as a documented positive test for anti-CMV IgG. * High-risk for CMV: HCT from related, unrelated, or haploidentical donor with post-transplant cyclophosphamide for graft-versus-host-disease (GVHD) prophylaxis; or HCT from related or unrelated donor with at least one mismatch at any of the following human leukocyte antigen (HLA) gene loci (HLA-A, B, C, and DRB1); or HCT from related or unrelated donor with myeloablative conditioning. * Persons of nonchildbearing potential or of childbearing potential with negative urine or serum pregnancy test on the day of first study injection. * Persons of childbearing potential who have practiced adequate contraception or have abstained from all activities that could result in pregnancy for at least 28 days prior to the first dose. * Persons of childbearing potential who have agreed to continue adequate contraception or abstain from all activities that could result in pregnancy through 3 months after last study injection. * Persons who are not currently breast/chestfeeding. * Willingness to comply with study procedures and provide written informed consent. Exclusion Criteria: * History of a 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 study procedures. * A documented positive human immunodeficiency virus (HIV) test. * Treatment w…

Questions worth asking your doctor

Bring these to your next appointment. They're a starting point for a shared conversation — not a sign you qualify or a recommendation to enrol.

1Based on my diagnosis and history, is this trial worth exploring for me — or is there a standard treatment we should try first?
2What does this trial's phase tell us about how much is already known about its safety and benefit?
3What would taking part actually involve for me — visits, tests, time, and travel?
4What are the known and possible risks or side effects I should weigh, and how would they be monitored?
5If this trial isn't the right fit, what other options or trials would you suggest I look into?

Generated to help you prepare — always confirm anything about your own eligibility and care with the study team and your doctor.

Questions for the trial coordinator

The trial coordinator is the person who runs the study day to day. These cover the practical side — logistics, costs, and what taking part would actually mean for your life. The study team confirms whether you meet the criteria; these are questions to ask, not a sign you qualify.

1What does taking part actually involve week to week — how many visits, where, and how long does each one take?
2What costs are covered by the study, and what might I have to pay for myself, including travel, parking, or time off work?
3What happens during screening, and what happens if the study team confirms I don't meet the criteria after those tests?
4Who pays for the scans, blood work, and other tests the trial requires — the study, my insurance, or me?
5How will being in the trial affect my regular care, and will my own doctor stay informed and involved?
6Can I leave the trial at any point if I change my mind, and what would happen to my care if I do?

A starting point for the conversation — always confirm anything about your own eligibility, costs, and care with the study team and your doctor.

What they're measuring

Time to the First Occurrence of an CS-CMVi Event as Measured by initiation of anti-CMV Antiviral Therapy

Timeframe: Day 100 to Month 9

Number of Participants with Solicited Local and Systemic Reactogenicity Adverse Reactions (ARs)

Timeframe: Up to Day 187 (7 days after last study injection)

Number of Unsolicited Adverse Events (AEs)

Timeframe: Up to Day 205 (25 days after last study injection)

Number of Participants with Severe AEs

Timeframe: Up to Day 365

Number of Participants with Serious Adverse Events (SAEs)

Timeframe: Up to Day 365

Number of Participants with Grade ≥3 Acute Graft-Versus-Host Disease (GVHD)

Timeframe: Up to Day 365

Trial details

NCT IDNCT05683457

SponsorModernaTX, Inc.

Sponsor typeINDUSTRY

Study typeINTERVENTIONAL

Primary completion2026-08-01

View on ClinicalTrials.gov More Cytomegalovirus Infection trials

Plain-language summary

Who can participate

Age range

18 Years

Sex

ALL

See this in plain English?

AI-rewrites the medical criteria so a patient or caregiver can understand them. Always confirm with the trial site.

What they're measuring

Time to the First Occurrence of an CS-CMVi Event as Measured by initiation of anti-CMV Antiviral Therapy

Timeframe: Day 100 to Month 9

Number of Participants with Solicited Local and Systemic Reactogenicity Adverse Reactions (ARs)

Timeframe: Up to Day 187 (7 days after last study injection)

Number of Unsolicited Adverse Events (AEs)

Timeframe: Up to Day 205 (25 days after last study injection)

Number of Participants with Severe AEs

Timeframe: Up to Day 365

Number of Participants with Serious Adverse Events (SAEs)

Timeframe: Up to Day 365

Number of Participants with Grade ≥3 Acute Graft-Versus-Host Disease (GVHD)

Timeframe: Up to Day 365