Cytomegalovirus InfectionPhase 2NCT05683457
A Study to Evaluate the Efficacy, Safety, and Immunogenicity of mRNA-1647 Cytomegalovirus (CMV) Vaccine in Allogenic Hematopoietic Cell Transplantation (HCT) Participants.
A Phase 2 study testing mRNA-1647 in people with Cytomegalovirus Infection, run by ModernaTX, Inc. at 3 sites in United States.
Trial 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. Read more about this study
- Who is it for?
- Ages 18 years and older
- Conditions the study is for
- Cytomegalovirus Infection
- What is being tested?
- mRNA-1647
- Type of treatment
- Injection or infusion
- Could I receive a placebo?
- Yes, some participants may receive a placebo
- How many people
- 84 participants
- Where
- 3 sitesUnited States
- Study dates
- 5 Apr 2023to 6 Mar 2027
- Phase
- Phase 2
- Are there results?
- Not yet: the study is under way
Key requirements
Who can take part, as listed by the sponsor. Only the study team can confirm whether you are eligible, so take this list to your doctor.
- Ages 18 years and older
- All sexes
- No healthy volunteers
- Adult, Older adult
Who may be able to join
- 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.
Who cannot join
- 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 with alemtuzumab (Campath®), antithymocyte globulin (ATG), or any equivalent in-vivo T cell depleting agent within 12 months.
- HCT with ex-vivo T cell depletion.
- Low risk for CMV: HCT from related or unrelated donor with reduced intensity conditioning (RIC) and no other high-risk features.
- History of prior hematopoietic cell transplantation within 12 months.
- Receipt of prior investigational CMV vaccines or participation in another CMV therapeutic study that may interfere with study outcome measures as determined by the Investigator.
- Suspected or known allergic reaction to any component of any mRNA vaccine or its excipients.
Trial locations and contacts
3 sites in 1 country.
United States3 sites
Dana-Farber Cancer Institute
Boston, Massachusetts, 02215
Fred Hutchinson Cancer Center
Seattle, Washington, 98109
Washington University School of Medicine
St Louis, Missouri, 63110
About this study
Official title: A Phase 2, Observer-Blind, Placebo-Controlled Proof-of-Concept Trial to Evaluate Efficacy, Safety, and Immunogenicity of mRNA-1647 Cytomegalovirus Vaccine in Patients Who Have Undergone Allogeneic Hematopoietic Cell Transplantation (HCT)
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.
- Conditions
- Cytomegalovirus Infection
- Being tested
- mRNA-1647, Placebo
- Keywords
- Human cytomegalovirus, Human Herpesvirus, mRNA-1647, Moderna, CMV, Cytomegalovirus Vaccine, Cytomegalovirus Infections, Cytomegalovirus Congenital, Virus Disease, Infection Viral, DNA Virus Infections, Messenger RNA, Hematopoietic cell transplantation
- Medical subject headings
- Cytomegalovirus Infections, Herpes Simplex, Virus Diseases, DNA Virus Infections
What participants receive
What participants receive. In a randomised study each person is assigned to one group by chance.
mRNA-1647Biological
Lyophilized product that is reconstituted with 0.9% sodium chloride (normal saline).
PlaceboBiological
0.9% sodium chloride (normal saline) injection
| Study group | Role | What they receive |
|---|---|---|
| mRNA-1647 | Experimental | Participants will receive mRNA-1647 by intramuscular (IM) injection on Day 42, Day 67, and Day 92, and a booster dose on Day 180. Receives: Biological: mRNA-1647 |
| Placebo | Placebo comparator | Participants will receive mRNA-1647 matching placebo by IM injection on Day 42, Day 67, and Day 92, and a booster dose on Day 180. Receives: Biological: Placebo |
What is being measured
The primary outcome is the main question the study is designed to answer.
Time to the First Occurrence of an CS-CMVi Event as Measured by initiation of anti-CMV Antiviral Therapy
Measured: Day 100 to Month 9
Number of Participants with Solicited Local and Systemic Reactogenicity Adverse Reactions (ARs)
Measured: Up to Day 187 (7 days after last study injection)
Number of Unsolicited Adverse Events (AEs)
Measured: Up to Day 205 (25 days after last study injection)
Number of Participants with Severe AEs
Measured: Up to Day 365
Number of Participants with Serious Adverse Events (SAEs)
Measured: Up to Day 365
Number of Participants with Grade ≥3 Acute Graft-Versus-Host Disease (GVHD)
Measured: Up to Day 365
Secondary outcomes (10)
Number of Participants with First Occurrence of All CS-CMVi Events as Measured by Initiation of Anti-CMV Antiviral and/or End-Organ Disease
Measured: Day 100 to Month 9
Number of Participants with an Occurrence of CMV Viremia
CMV Viremia is defined as ≥300 international units/milliliters (IU/mL).
Measured: Day 100 to Month 9
Number of Participants with CMV End-Organ Disease
Measured: Day 100 to Month 9
Duration of CMV Viremia
Measured: Day 100 to Month 9
Duration of CMV Treatment
Measured: Day 100 to Month 9
Number of Participants with Non-Relapse Mortality at 9 Months Post-HCT.
Measured: Month 9
Titer of CMV-Specific Neutralizing Antibody (nAb)
Measured: Days 42, 67, 92, 117, 180, 205 and 270
Geometric Mean Titer (GMT) of Anti-gB-Specific Immunoglobulin G (IgG) and Anti-Pentamer-Specific IgG as Measured by Enzyme-Linked Immunosorbent Assay (ELISA)
Measured: Days 42, 67, 92, 117, 180, 205 and 270
Geometric Mean Concentration (GMC) of Anti-gB-Specific Immunoglobulin G (IgG) and Anti-Pentamer-Specific IgG as Measured by Enzyme-Linked Immunosorbent Assay (ELISA)
Measured: Days 42, 67, 92, 117, 180, 205 and 270
Geometric Mean Fold Rise (GMFR) of Postbaseline/Baseline GMTs or GMCs
Measured: Days 42, 67, 92, 117, 180, 205 and 270
Timeline
From the start of the study to its completion; the mark is today. Estimated dates are the sponsor’s plan.
- First posted13 Jan 2023
- Study start5 Apr 2023
- Primary completion6 Mar 2027 (estimated)
- Study completion6 Mar 2027 (estimated)
Resources
- Official record on ClinicalTrials.govThe registry entry this page is built from, with its full change history.
- Other trials for Cytomegalovirus InfectionStudies of the same condition, open and under way.
- More trials run by ModernaTX, Inc.The sponsor's other registered studies.
- What the trial phases meanHow a treatment moves from first tests in people to approval.
More details
For doctors and researchers: how the study is designed, who runs it, and its registry IDs.
Study design
- Study type
- Interventional
- Phase
- Phase 2
- Primary purpose
- Prevention
- Allocation
- Randomised
- Intervention model
- Parallel groups
- Masking
- Triple blind
- Who is masked
- Participant, Investigator, Outcomes assessor
- Enrolment
- 84 participants (actual)
Sponsor and investigators
- Lead sponsor
- ModernaTX, Inc.
- Sponsor type
- Industry (pharma, biotech, devices)
- Responsible party
- Sponsor
IDs, dates and publications
- ClinicalTrials.gov ID
- NCT05683457
- Sponsor's protocol ID
- mRNA-1647-P205
- Status last verified
- Aug 2026
- First submitted
- 4 Jan 2023
- Last updated
- 10 Aug 2026
- Results posted
- No
- Data monitoring committee
- Yes
- FDA-regulated drug
- Yes
- FDA-regulated device
- No
Study at a glance
From the registry record, last updated by the sponsor on 10 Aug 2026. Recruitment status is as the sponsor reported it: confirm with the study team.
- Official title
- A Phase 2, Observer-Blind, Placebo-Controlled Proof-of-Concept Trial to Evaluate Efficacy, Safety, and Immunogenicity of mRNA-1647 Cytomegalovirus Vaccine in Patients Who Have Undergone Allogeneic Hematopoietic Cell Transplantation (HCT)
- ClinicalTrials.gov ID
- NCT05683457
- Acronym / sponsor ID
- mRNA-1647-P205
- Conditions
- Cytomegalovirus Infection
- Keywords
- Human cytomegalovirus, Human Herpesvirus, mRNA-1647, Moderna, CMV, Cytomegalovirus Vaccine, Cytomegalovirus Infections, Cytomegalovirus Congenital
- Phase
- Phase 2
- Study type
- Interventional
- Recruitment status
- Active, not recruiting
- Enrolment
- 84 participants (actual)
- Lead sponsor
- ModernaTX, Inc.Industry (pharma, biotech, devices)
- Study start
- 5 Apr 2023 (actual)
- Primary completion
- 6 Mar 2027 (estimated)
- Study completion
- 6 Mar 2027 (estimated)
- First posted
- 13 Jan 2023 (actual)
- Results
- Not posted in the source record
Clinical summary
The research question as the sponsor registered it. This describes what the study plans to test, not what it found.
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.
Study design
- Primary purpose
- Prevention
- Allocation
- Randomised
- Intervention model
- Parallel groups
- Masking
- Triple blind (participant, investigator, outcomes assessor)
- Number of arms
- 2
| Arm | Type | Receives |
|---|---|---|
| mRNA-1647 | Experimental | Biological: mRNA-1647Participants will receive mRNA-1647 by intramuscular (IM) injection on Day 42, Day 67, and Day 92, and a booster dose on Day 180. |
| Placebo | Placebo comparator | Biological: PlaceboParticipants will receive mRNA-1647 matching placebo by IM injection on Day 42, Day 67, and Day 92, and a booster dose on Day 180. |
Who may qualify
- Ages
- 18 years and older
- Sex
- All
- Healthy volunteers
- Not accepted
- Age groups
- Adult, Older adult
Key inclusion criteria (8 listed)
- 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.
Key exclusion criteria (8 listed)
- 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 with alemtuzumab (Campath®), antithymocyte globulin (ATG), or any equivalent in-vivo T cell depleting agent within 12 months.
- HCT with ex-vivo T cell depletion.
- Low risk for CMV: HCT from related or unrelated donor with reduced intensity conditioning (RIC) and no other high-risk features.
Eligibility is decided by the study team after screening; this overview does not establish that a patient qualifies. Full inclusion and exclusion criteria.
Interventions
| Intervention | Type | Arms |
|---|---|---|
| mRNA-1647Lyophilized product that is reconstituted with 0.9% sodium chloride (normal saline). | Biological | mRNA-1647 |
| Placebo0.9% sodium chloride (normal saline) injection | Biological | Placebo |
Primary outcome
Time to the First Occurrence of an CS-CMVi Event as Measured by initiation of anti-CMV Antiviral Therapy
Time frame: Day 100 to Month 9
Number of Participants with Solicited Local and Systemic Reactogenicity Adverse Reactions (ARs)
Time frame: Up to Day 187 (7 days after last study injection)
Number of Unsolicited Adverse Events (AEs)
Time frame: Up to Day 205 (25 days after last study injection)
Number of Participants with Severe AEs
Time frame: Up to Day 365
Number of Participants with Serious Adverse Events (SAEs)
Time frame: Up to Day 365
Number of Participants with Grade ≥3 Acute Graft-Versus-Host Disease (GVHD)
Time frame: Up to Day 365
10 secondary outcomes
Number of Participants with First Occurrence of All CS-CMVi Events as Measured by Initiation of Anti-CMV Antiviral and/or End-Organ Disease
Time frame: Day 100 to Month 9
Number of Participants with an Occurrence of CMV Viremia
Time frame: Day 100 to Month 9
Number of Participants with CMV End-Organ Disease
Time frame: Day 100 to Month 9
Duration of CMV Viremia
Time frame: Day 100 to Month 9
Duration of CMV Treatment
Time frame: Day 100 to Month 9
Number of Participants with Non-Relapse Mortality at 9 Months Post-HCT.
Time frame: Month 9
Titer of CMV-Specific Neutralizing Antibody (nAb)
Time frame: Days 42, 67, 92, 117, 180, 205 and 270
Geometric Mean Titer (GMT) of Anti-gB-Specific Immunoglobulin G (IgG) and Anti-Pentamer-Specific IgG as Measured by Enzyme-Linked Immunosorbent Assay (ELISA)
Time frame: Days 42, 67, 92, 117, 180, 205 and 270
Geometric Mean Concentration (GMC) of Anti-gB-Specific Immunoglobulin G (IgG) and Anti-Pentamer-Specific IgG as Measured by Enzyme-Linked Immunosorbent Assay (ELISA)
Time frame: Days 42, 67, 92, 117, 180, 205 and 270
Geometric Mean Fold Rise (GMFR) of Postbaseline/Baseline GMTs or GMCs
Time frame: Days 42, 67, 92, 117, 180, 205 and 270
Results and safety
This study is still under way. Results are not available in the source record yet.
Research links
- Official record on ClinicalTrials.govLast updated by the sponsor 10 Aug 2026.
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Referral and contact
AzTrials does not enrol participants or take referrals. Contact the study team or a site listed below; they decide who can take part. This study is not recruiting at the moment.
The record lists no contact. Use the official record to reach the sponsor.
3 sites in 1 country: see every site and its status.
Questions about this trial
What is this clinical trial studying?
A Phase 2 study testing mRNA-1647 in people with Cytomegalovirus Infection, run by ModernaTX, Inc. at 3 sites in United States.
The full registered description is in the About this study section and the official record.
Who may be eligible to take part?
The sponsor lists 8 inclusion and 8 exclusion criteria. Eligibility is decided by the study team after screening, so read the full criteria and contact a listed site.
Is this clinical trial currently recruiting?
The record says: under way, not looking for participants, as of the sponsor's last update on 10 Aug 2026. Status can change between updates, so confirm with the study contact before making plans.
Where is the study taking place?
The record lists 3 sites in United States. Whether a site is taking part right now should be confirmed with that site. See every site.
What are the possible benefits and risks?
They depend on the study and the treatment, and no study can promise a benefit. Some participants in this study may receive a placebo. The study team explains the known risks during informed consent, before anyone joins; the record itself does not list them.
What does this phase mean?
Phase 2 studies give the treatment to a larger group to see whether it has the intended effect and to keep checking safety.
Not every study follows the same path, and some studies (observational studies, device studies) have no phase.
Are results available for this study?
This study is still under way. Results are not available in the source record yet.
How can a doctor refer a patient or contact the research team?
The record lists no contact. The official record names the sponsor, who can be asked directly. AzTrials does not enrol participants or take referrals.
What does the primary outcome measure?
Time to the First Occurrence of an CS-CMVi Event as Measured by initiation of anti-CMV Antiviral Therapy (time frame: Day 100 to Month 9). The study lists 6 primary outcomes in all. It is what the study was designed to measure, not a finding.
Where can I read the original study information?
Does a listing mean the treatment is approved or proven to work?
No. A listing means the study is registered. It does not show that the treatment is safe, works, or is approved by a regulator.
How often is this information updated?
AzTrials copies changed records from ClinicalTrials.gov every night and reloads the whole registry every week. The sponsor last updated this record on 10 Aug 2026.