A Study of mRNA-1647 Cytomegalovirus Vaccine in Liver Transplant Candidates and Recipients

A Phase 2, Observer-Blind, Placebo-Controlled, Proof-of-Concept Trial to Evaluate the Efficacy, Safety, and Immunogenicity of mRNA-1647 Cytomegalovirus Vaccine in Liver Transplant Candidates and Recipients

The purpose of this study is to assess the effect of pre-transplant mRNA-1647 on post-transplant cytomegalovirus (CMV) virologic outcomes, anti-CMV antiviral use, and clinical outcomes in CMV-seropositive and CMV-seronegative liver transplant candidates who receive transplants and to assess the safety, reactogenicity, and immunogenicity of mRNA-1647 in all participants.

Inclusion Criteria:

• Having a negative (that is, CMV-seronegative) or a positive (that is, CMV-seropositive) result using a blood IgG assay performed at the central laboratory or a previously documented seropositive result.
• Listed and anticipated to receive their first deceased donor or living donor liver transplant within 2 months to 12 months of enrollment.
• A person of nonchildbearing potential, as defined in the protocol.
• 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 the first injection, and agreement to continue adequate contraception or abstinence through 3 months following last study injection.

Exclusion Criteria:

• Listed as "status 1A" for liver transplant.
• Hypersensitivity to acyclovir, ganciclovir, or valganciclovir.
• Previous receipt of a solid organ or hematopoietic transplant.
• Listed for or anticipated to receive an organ transplant other than liver, either simultaneously or sequentially.
• 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, including mRNA-1647, or its excipients.
• Human immunodeficiency virus (HIV) infection (based on documented testing performed during the transplant evaluation process and no clinical suspicion of HIV infection).
• Prior (ever) receipt of a stem cell transplant (peripheral blood stem cell, marrow, cord blood).
• Any medical, psychiatric, or occupational condition, including reported history of drug or alcohol abuse, 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.

Note: Other inclusion and exclusion criteria may apply.