mRNA Vaccine for Cytomegalovirus (CMV)

Enrolling by invitation at 5 trial locations

Age: 18 - 65

Sex: Any

Trial Phase: Phase 2

Sponsor: ModernaTX, Inc.

Disqualifiers: Other CMV vaccines, Medical conditions, others

No Placebo Group All trial participants will receive the active study treatment (no placebo)

Prior Safety Data This treatment has passed at least one previous human trial

Compensation: Varies

Number of Visits: 18

What You Need to Know Before You Apply

What is the purpose of this trial?

This trial tests an mRNA vaccine designed to protect against cytomegalovirus (CMV), a virus many people carry unknowingly. The goal is to determine how long the immune response lasts and whether a booster shot enhances it. Participants from the earlier phase of the study who received the vaccine (not a placebo) can join. It suits those who are either CMV-positive or CMV-negative and have previously participated in the initial study. As a Phase 2 trial, this research measures the treatment's effectiveness in a smaller group, allowing participants to contribute to important findings.

Do I need to stop my current medications for this trial?

The trial information does not specify whether you need to stop taking your current medications. It's best to discuss this with the trial team or your doctor.

Is there any evidence suggesting that the mRNA-1647 vaccine is likely to be safe for humans?

Previous studies have shown that mRNA-1647 is generally safe and well-tolerated. Research demonstrated that at all dose levels, it triggered immune responses specific to the substances causing an immune reaction. An independent data safety monitoring board reviewed the vaccine, conducting a thorough safety check and finding no major issues. Overall, the evidence suggests that mRNA-1647 is safe for use in humans. ^{1 2 3 4 5}

Why do researchers think this study treatment might be promising?

Researchers are excited about the mRNA-1647 vaccine for cytomegalovirus (CMV) because it uses cutting-edge mRNA technology to train the immune system to recognize and combat the virus. Unlike traditional treatments that often involve antiviral medications, mRNA-1647 aims to prevent CMV infection by prompting the body to produce proteins that trigger an immune response against the virus. This approach is innovative because it not only targets the virus directly but also offers a preventative strategy, potentially reducing the risk of CMV-related complications in vulnerable populations.

What evidence suggests that the mRNA-1647 vaccine could be effective for cytomegalovirus?

Research has shown that the mRNA-1647 vaccine can help the body combat CMV, a virus affecting adults. Early studies found the vaccine to be generally safe. These studies also demonstrated that the vaccine could prevent CMV infection in 6% to 23% of cases, depending on the measurement of effectiveness. While these results are promising, further research is needed to fully understand the vaccine's efficacy. In this trial, participants may receive a booster dose of the mRNA-1647 vaccine to evaluate the duration of its protection and its safety, particularly with the booster dose. ^{1 3 6 7 8}

Are You a Good Fit for This Trial?

This trial is for adults who participated in a prior CMV vaccine study (mRNA-1647-P202) and received the mRNA-1647 vaccine, not placebo. They must have completed that study, be in good health as judged by the investigator, understand and agree to follow trial procedures, and provide written consent. Those previously vaccinated with any CMV vaccine other than mRNA-1647 or with conditions affecting safety assessments or adherence to procedures cannot join.

Inclusion Criteria

Understands and agrees to comply with the trial procedures and provides written informed consent.

According to the assessment of the Investigator, is in good general health and is capable of complying with trial procedures.

I was CMV negative at my initial and final study visits.

Exclusion Criteria

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 trial procedures, including any medical, psychiatric, or occupational condition that, in the opinion of the Investigator, might pose additional risk due to participation in the study or could interfere with the interpretation of study results.

I have not received any CMV vaccine except for mRNA-1647.

Timeline for a Trial Participant

Screening

Participants are screened for eligibility to participate in the trial

2-4 weeks

Primary Extension Phase

Participants who completed Study mRNA-1647-P202 will be followed every 6 months for 3 years to evaluate long-term immune persistence and safety.

3 years

Every 6 months

Optional Booster Phase

Participants may opt to receive a single booster dose of the mRNA-1647 vaccine or be followed without receiving the booster.

12 months

Followed until BP Month 12

Follow-up

Participants are monitored for safety and effectiveness after the optional booster phase.

6 months

What Are the Treatments Tested in This Trial?

Interventions

• mRNA-1647

Trial Overview

The focus of this extension study is on evaluating how long the immune response lasts from the mRNA-1647 vaccine given to both CMV-seronegative and CMV-seropositive adults. It's a continuation for participants who were part of an earlier phase where they received this experimental vaccine against Cytomegalovirus.

How Is the Trial Designed?

Group I: Primary Extension Phase Experimental Treatment 1 Intervention

CMV-seropositive and CMV-seronegative participants who completed Study mRNA-1647-P202 will be followed every 6 months for 3 years in this study after the final visit in Study mRNA-1647-P202.

Group II: Optional Booster Phase - Observational Group Experimental Treatment 1 Intervention

Participants who opted to enroll into the Observational Group will be followed in the optional BP until BP Month 12.

Group III: Optional Booster Phase - BD Recipients Experimental Treatment 1 Intervention

Participants who opted to enroll into the optional Booster Phase will receive a single mRNA-1647 vaccine dose.

Who Is Running the Clinical Trial?

ModernaTX, Inc.

Lead Sponsor

Trials

127

Recruited

66,790,000+

Dr. Stephen Hoge

ModernaTX, Inc.

Chief Medical Officer

MD from Harvard Medical School

Stéphane Bancel

ModernaTX, Inc.

Chief Executive Officer since 2011

MBA from Harvard Business School, MSc in Engineering from École Centrale Paris

Published Research Related to This Trial

Congenital cytomegalovirus (CMV) infection is the leading infectious cause of disability in newborns, highlighting the urgent need for effective vaccination to protect vulnerable populations.

Current research shows promise for a recombinant CMV glycoprotein B (gB) vaccine, which has demonstrated some efficacy in preventing CMV infection in young women, adolescents, and CMV-seronegative transplant recipients, indicating potential for broader immunization strategies.

NCBI (Pubmed)

pubmed.ncbi.nlm.nih.gov

Cytomegalovirus vaccines under clinical development. Schleiss, MR.[2022]

Certain high-risk groups, such as HIV-infected individuals, transplant patients, and newborns, are particularly vulnerable to diseases caused by human cytomegalovirus (CMV), highlighting the need for effective vaccination strategies.

While there are currently no licensed CMV vaccines for humans, various vaccine approaches, including protein subunit, DNA, and live attenuated vaccines, are being tested in clinical trials, showing promise in inducing protective immune responses against CMV.

NCBI (Pubmed)

pubmed.ncbi.nlm.nih.gov

Progress toward an elusive goal: current status of cytomegalovirus vaccines. Schleiss, MR., Heineman, TC.[2007]

A recent trial of a subunit glycoprotein B (gB) vaccine with the adjuvant MF59 showed promise in reducing CMV infections in postpartum women, indicating potential for effective CMV vaccination.

Various innovative vaccine strategies, including replicons and DNA vaccines, are currently in clinical trials, but the ideal formulation for a CMV vaccine is still being determined.

NCBI (Pubmed)

pubmed.ncbi.nlm.nih.gov

Vaccines for cytomegalovirus. Bernstein, DI.[2019]

Cytomegalovirus (CMV) poses significant health risks to infants and immunocompromised patients, highlighting the need for effective vaccines to prevent CMV-related diseases.

Current research is advancing the development of CMV vaccines, but understanding the specific immune responses needed for effective protection remains crucial before these vaccines can be widely implemented in clinical settings.

NCBI (Pubmed)

pubmed.ncbi.nlm.nih.gov

Progress in cytomegalovirus vaccine development. Schleiss, M.[2006]

The V160 CMV vaccine was found to be generally well-tolerated in both CMV-seronegative and seropositive adults, with no serious adverse events reported and only mild-to-moderate injection-site and systemic reactions observed.

The vaccine successfully elicited robust neutralizing antibody responses and T-cell activation, maintaining these levels for up to 12 months, indicating strong immunogenicity similar to that seen after natural CMV infection.

NCBI (Pubmed)

pubmed.ncbi.nlm.nih.gov

Phase 1 Clinical Trial of a Conditionally Replication-Defective Human Cytomegalovirus (CMV) Vaccine in CMV-Seronegative Subjects. Adler, SP., Lewis, N., Conlon, A., et al.[2020]

The study shows that a vaccine using lipid nanoparticles (LNP) with modified mRNA encoding CMV glycoproteins can generate strong and lasting neutralizing antibodies in both mice and nonhuman primates, indicating potential effectiveness against CMV infection.

An additional mRNA vaccine targeting the CMV T cell antigen pp65 was developed, which successfully produced robust T cell responses, suggesting that this mRNA/LNP platform can be tailored for different populations, such as pregnant women and transplant recipients.

NCBI (Pubmed)

pubmed.ncbi.nlm.nih.gov

Multi-antigenic human cytomegalovirus mRNA vaccines that elicit potent humoral and cell-mediated immunity. John, S., Yuzhakov, O., Woods, A., et al.[2018]

Citations

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Reflecting on Moderna's Phase 3 CMV Vaccine Readout

Today, we announced topline results from a Phase 3 pivotal trial evaluating the efficacy of mRNA-1647, our investigational cytomegalovirus (CMV ...

2.

cdc.gov

cdc.gov/acip/downloads/slides-2025-04-15-16/03-paris-CMV-508.pdf

Overview of mRNA-1647: Investigational CMV Vaccine

• 43-50% efficacy for CMV infection in 2 previous trials of recombinant gB candidate vaccine1 ... mRNA-1647 Phase 3 Efficacy Trial: Two Planned ...

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infectiousdiseaseadvisor.com

infectiousdiseaseadvisor.com/news/modernas-cmv-vaccine-candidate-misses-in-late-stage-trial/

Moderna's CMV Vaccine Candidate Misses in Late Stage ...

Vaccine efficacy against CMV infection was reported to be between 6% to 23% depending on the case definition used. Based on these findings, the ...

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pmc.ncbi.nlm.nih.gov

pmc.ncbi.nlm.nih.gov/articles/PMC11420795/

Results From a Phase 1 Randomized Clinical Trial - PMC

This phase 1, first-in-human trial demonstrated that mRNA-1647 has an acceptable safety profile in adults and elicits humoral and cellular immune responses.

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clinicaltrials.gov

clinicaltrials.gov/study/NCT05085366

NCT05085366 | A Study to Evaluate the Efficacy, Safety ...

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 ...

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pmc.ncbi.nlm.nih.gov

pmc.ncbi.nlm.nih.gov/articles/PMC10677300/

2892. Safety and Immunogenicity of mRNA-1647, an ...

Conclusion. mRNA-1647 was generally safe and well-tolerated and induced antigen-specific immune responses at all dose levels in both CMV- ...

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trials.modernatx.com

trials.modernatx.com/study/?id=mRNA-1647-P301

A Clinical Trial of a Cytomegalovirus (CMV) Vaccine ...

The purpose of this clinical trial is to evaluate the safety and efficacy of mRNA-1647 investigational vaccine against CMV and evaluate the safety of the mRNA- ...

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academic.oup.com

academic.oup.com/jid/article/230/3/e668/7628193

Results From a Phase 1 Randomized Clinical Trial | The ...

This phase 1, first-in-human trial demonstrated that mRNA-1647 has an acceptable safety profile in adults and elicits humoral and cellular immune responses.