Cytomegalovirus (CMV) Vaccine in Orthotopic Liver Transplant Candidates

Inclusion Criteria:

1. Subject must be able to understand and provide informed consent

2. Negative for Cytomegalovirus (CMV) IgG antibody as assessed in a Clinical LaboratoryImprovement Amendments (CLIA)-certified laboratory within 12 months of enrollment,and no history of prior positive CMV serology (IgG antibody)

3. Negative human immunodeficiency virus (HIV) testing and no clinical suspicion of HIVinfection

4. Planned for a first living donor liver transplant or listed/anticipated to be listedfor a first deceased donor liver transplant.

5. Anticipated to receive a liver transplant within 1-12 months

6. For individuals of reproductive potential, a negative serum or urine pregnancy testwithin 72 hours prior to enrollment. NOTE: Individuals of reproductive potential aredefined as individuals who have reached menarche and who have not beenpost-menopausal for at least 12 consecutive months with follicle-stimulating hormone (FSH) >=40 IU/mL or 24 consecutive months if an FSH is not available, i.e., who havehad menses within the preceding 24 months, and have not undergone a sterilizationprocedure (e.g., hysterectomy, bilateral oophorectomy, or salpingectomy)

7. Participants who are able to impregnate or become pregnant (i.e., of reproductivepotential) and are participating in sexual activity that could lead to pregnancymust agree to practice contraception/birth control (hormonal or barrier method) oragree to not participate in a conception process (e.g., active attempt to becomepregnant or to impregnate, sperm donation, in vitro fertilization) for at least 1month following the last vaccine/placebo dose. For acceptable contraception methodsthat are more than 80 percent effective, see Food and Drug Administration (FDA)Office of Women's Health (http://www.fda.gov/birthcontrol)

8. The most recent platelet count is >= 20,000 cells/mm^3 within 3 months prior toenrollment and in the opinion of the investigator, has not decreased < 20,000cells/mm^3 at time of study IP administration.

Eligibility criteria required: Dose 2:

1. Most recent platelet count >= 20,000 cells/mm^3 within 3 months prior to enrollmentand in the opinion of the investigator, has not decreased < 20,000 cells/mm^3 sincelast result

2. For women of reproductive potential as defined previously, a negative serum or urinepregnancy test (performed within 72 hours)

Exclusion Criteria:

1. Women who are breastfeeding or planning to breastfeed

2. Prior Cytomegalovirus (CMV) vaccination

3. Receipt of immunoglobulin or CMV-specific immunoglobulin within the last 3 months (this includes coronavirus disease (COVID) convalescent plasma)

4. Currently enrolled in another interventional study that, in the investigator'sopinion, could affect the evaluation of safety and/or vaccine effect outcomes

5. Prior (ever) receipt of a stem cell transplant (Peripheral blood stem cell (PBSC),marrow, cord blood, etc.)

6. Receipt of immunosuppression:

• Within the last 3 months prior to randomization:

• Systemic Chemotherapy or immunotherapy for cancer in the last 3 months (localized therapy for hepatocellular carcinoma [HCC] such aschemoembolization, Y-90 are not considered "systemic chemotherapy" and arenot excluded)

• Systemic immunosuppressive agents (e.g., cyclophosphamide, methotrexate,mycophenolate, azathioprine, calcineurin inhibitors, mTOR inhibitors,TNF-alpha inhibitors) and/or combination immunosuppressive drugs for anyautoimmune or other conditions in the last 3 months except corticosteroidsas below

• Within the last 28 days prior to randomization: averaged daily corticosteroidtherapy dose ≥20 mg of prednisone equivalent

• Within the last 6 months prior to randomization: receipt of T- or Bcelldepleting agents (e.g. ATG, Alemtuzumab, Rituximab)

7. Transplant status 1A or in the opinion of the investigator is likely to receive atransplant within the next month

8. At the time of randomization, either listed for, or, in the opinion of theinvestigator, likely to receive any non-liver organ transplant

9. Receipt of a clinical vaccine < 14 days before or planned to receive a clinicalvaccine <14 days after the study agent

10. Known allergy to any component of the study agent

11. Past or current medical problems or findings from physical examination or laboratorytesting that are not listed above, which, in the opinion of the investigator, maypose additional risks from participation in the study, may interfere with theparticipant's ability to comply with study requirements or that may impact thequality or interpretation of the data obtained from the study

Exclusion criteria required: Dose 2:

1. Anaphylaxis or other severe reaction (Grade 4) considered definitely or probablyattributable to dose 1

2. Receipt of liver transplant prior to dose 2

3. The participant must not have any severe acute illness or other factor, that, in theopinion of the investigator, requires postponement of dose 2 because of safetyconcerns. The participant can be re-evaluated for eligibility throughout the windowof eligibility for the dose 2, once the illness or other factor has improved orresolved

4. Receipt of a clinical vaccine < 14 days before or planned to receive a clinicalvaccine <14 days after the study agent