Triplex Vaccine in Preventing CMV Infection in Patients Undergoing Hematopoietic Stem Cell Transplantation
Active, enrolledPhase 2Results postedLast updated 14 November 2025
What this trial tests
Phase 2 trial testing Letermovir in Accelerated Phase Chronic Myelogenous Leukemia, BCR-ABL1 Positive in 7 participants. Participants enrolled and being followed up; not accepting new ones.
18 and older, any sex, with Accelerated Phase Chronic Myelogenous Leukemia, BCR-ABL1 Positive or Acute Lymphoblastic Leukemia. Patients with the condition only — healthy volunteers not accepted.
Results — posted to ClinicalTrials.gov
Per-arm endpoint measurements with 95% confidence intervals where reported. Source: trial results section.
Number of Participants With Cytomegalovirus (CMV) EventsPrimary· From Day 100 to Day 180 post-hematopoietic stem cell transplant (HCT)
Cytomegalovirus (CMV) event was defined as CMV reactivation (DNAemia \>625 IU/ml by qPCR), viremia treated by antivirals, or detection of CMV by tissue histology (end-organ disease), from Day 100 post-HCT to Day 180 post-HCT. Trial participants were quantitatively monitored for viremia, by plasma qPCR test once every two weeks (+/- 5d) from Day 100 to Day 180. CMV monitoring used standard qPCR clinical laboratory methods to evaluate CMV viral load and possible vaccine failure.
Group
Value
95% CI
Arm I (Letermovir, Triplex)
0
Arm II (Letermovir, Placebo)
0
Non-Relapse Mortality at Day 180 Post-TransplantSecondary· From time of transplant (Day 0) to Day 365
Non-relapse mortality (NRM) was defined as death without recurrent or progressive disease after transplant. NRM was estimated with the use of cumulative incidence curves, with relapse viewed as a competing risk.
Group
Value
95% CI
Arm I (Letermovir, Triplex)
0
NA – NA
Arm II (Letermovir, Placebo)
0
NA – NA
Number of Participants With Severe (Grade 3-4) Acute Graft Versus Host Disease (GVHD) at Day 100Secondary· From time of transplant (Day 0) to Day 100
Acute GVHD was assessed and graded according to the Keystone Consensus grading system (Przepiorka, D., et al., 1994 Consensus Conference on Acute GVHD Grading).
Group
Value
95% CI
Arm I (Letermovir, Triplex)
0
Arm II (Letermovir, Placebo)
0
Number of Grade 3-4 Adverse EventsSecondary· From time of transplant (Day 0) to Day 365
Adverse events probably or definitely related to the vaccination and modified vaccinia Ankara vector persistence were evaluated by NCI Common Terminology Criteria for Adverse Events v5.0.
Group
Value
95% CI
Arm I (Letermovir, Triplex)
0
Arm II (Letermovir, Placebo)
0
Duration of ViremiaSecondary· From time of transplant (Day 0) to Day 200
Duration of viremia was defined as the number of days from CMV qPCR \>625 IU/mL to serum viral clearance (no detectable CMV DNA in serial blood samples).
Group
Value
95% CI
Arm I (Letermovir, Triplex)
NA
NA – NA
Arm II (Letermovir, Placebo)
NA
NA – NA
Number of Patients With Recurrence of CMV ViremiaSecondary· From time of transplant (Day 0) to Day 200
CMV viremia was defined CMV qPCR \>625 IU/mL from samples collected within the past 7 days.
Group
Value
95% CI
Arm I (Letermovir, Triplex)
0
Arm II (Letermovir, Placebo)
0
Days From Transplant to ANC EngraftmentSecondary· From time of transplant to date of ANC engraftment, up to Day 365.
Date of ANC engraftment was defined as the first date of ANC of ≥ 0.5 x 109/L achieved for 3 consecutive lab tests on 3 different days.
Group
Value
95% CI
Arm I (Letermovir, Triplex)
17
14 – 18
Arm II (Letermovir, Placebo)
16
14 – 17
Cumulative Incidence of Acute GVHDSecondary· From time of transplant (Day 0) to Day 100
Acute graft versus host disease is graded according to the 1994 Keystone Consensus Grading. The first day of acute GVHD onset was used to calculate the cumulative incidence. Relapse/death prior to onset was considered competing events.
Group
Value
95% CI
Arm I (Letermovir, Triplex)
25
5 – 100
Arm II (Letermovir, Placebo)
0
NA – NA
Cumulative Incidence of Chronic GVHD at Day 365Secondary· From time of transplant (Day 0) to Day 365
Cumulative incidence of Chronic GVHD (cGVHD) was estimated with the use of cumulative incidence curves. The first day of cGVHD onset was used to calculate the cumulative incidence. Relapse/death prior to onset was considered competing events.
Group
Value
95% CI
Arm I (Letermovir, Triplex)
33
7 – 100
Arm II (Letermovir, Placebo)
0
NA – NA
Cumulative Incidence of Relapse at Day 365Secondary· From time of transplant (Day 0) to Day 365
Cumulative incidence of relapse was estimated with the use of cumulative incidence curves, with death viewed as a competing risk.
Group
Value
95% CI
Arm I (Letermovir, Triplex)
0
NA – NA
Arm II (Letermovir, Placebo)
0
NA – NA
Number Of Participants Died at Day 365Secondary· From time of transplant (Day 0) to Day 365
Number of participants, who died due to all causes, at Day 365 post-transplant.
Group
Value
95% CI
Arm I (Letermovir, Triplex)
0
Arm II (Letermovir, Placebo)
0
Overall Survival at Day 365Secondary· From time of transplant (Day 0) to Day 365
Estimates was calculated using the Kaplan-Meier method, Greenwood formula was used to calculate SE, and loglog transformation method was used to construct 95% confidence intervals. Each patient's vital status was monitored per clinical standard operating procedure. For this endpoint failure is defined as death (from any cause). Patients not experiencing a death event was censored at his/her date of last contact.
Group
Value
95% CI
Arm I (Letermovir, Triplex)
100
100 – 100
Arm II (Letermovir, Placebo)
100
100 – 100
Adverse events — posted to ClinicalTrials.gov
Time frame: Adverse events and all-cause mortality were monitored/assessed at Day 100, 114, 128, 140, 180, 210-240, 270 and 365..
Reporting threshold: 0%.
Adverse-event reports describe events observed during the trial — not all are caused by the drug.
This phase II trial studies how well Triplex vaccine works in preventing cytomegalovirus (CMV) infection in patients undergoing a hematopoietic stem cell transplantation. CMV is a virus that may be carried for life and does not cause illness in most healthy individuals. However, in people whose immune systems are lowered (such as those undergoing stem cell transplantation), CMV can reproduce and cause disease and even death. The Triplex vaccine is made up of 3 small pieces of CMV deoxyribonucleic acid (DNA) (the chemical form of genes) placed into a weakened virus called modified vaccinia Ankara (MVA) that may help produce immunity (the ability to recognize and respond to an infection) and reduce the risk of developing complications related to CMV infection.
Publications & conference data
8 peer-reviewed publications reference this trial (live from Europe PMC):
NCT07020533 — A Vaccine (CMV-MVA Triplex Vaccine) for the Enhancement of CMV-Specific Immunity and the Prevention of CMV Viremia in Pa
· Phase 1
· recruiting
NCT07199465 — A Clinical Study of Letermovir (MK-8228) in Children and Adolescents Who Receive a Kidney Transplant (KT) (MK-8228-077)
· Phase 1
· recruiting
NCT07488728 — Letermovir Prophylaxis in Children With EBV-Positive T/NK-Cell Lymphoproliferative Disease and Refractory/Relapsed EBV-A
· NA
· recruiting
NCT07079735 — Valganciclovir vs. Letermovir for CMV Prophylaxis in Heart Transplant
· Phase 2, PHASE3
· recruiting
NCT06920251 — Phase II Trials of Letermovir Prophylaxis in Patients With RRMM Undergoing Elranatamab Therapy
· Phase 2
· recruiting
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Currently open trials in the same condition.
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NCT02506933 — Multi-antigen CMV-MVA Triplex Vaccine in Reducing CMV Complications in Patients Previously Infected With CMV and Undergo
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Other City of Hope Medical Center trials
Trials by the same sponsor.
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Publications: Europe PMC API search by NCT ID, retrieved 10 June 2026
Drug + disease cross-links: matched in real time against Drug Landscape's normalised drug + company + condition tables
Sponsor: as reported to ClinicalTrials.gov by City of Hope Medical Center
Last refreshed: 14 November 2025
Drug Landscape aggregates and links these public records for informational use only. Always verify against the primary source before clinical or regulatory decisions. Canonical URL: https://druglandscape.com/trial/NCT04060277.