Phase 1b Study of CMV-MVA Triplex Vaccine to Boost CMV Immunity and Prevent CMV Infection in Haploidentical Stem Cell Donors and Recipients

What this Trial Is About

Researchers are evaluating the safety, side effects, and effectiveness of the CMV-modified vaccinia Ankara MVA Triplex vaccine in enhancing immunity against cytomegalovirus CMV and preventing CMV viremia in patients undergoing haploidentical hematopoietic stem cell transplantation haploHCT. HaploHCT is commonly used for patients without matched donors but carries a higher risk of significant CMV infection, which can cause complications and death. Vaccination is being studied as a preventative approach to reduce these risks in immunocompromised patients. Donors receive one intramuscular dose of the CMV-MVA Triplex vaccine followed by granulocyte colony stimulating factor G-CSF to mobilize stem cells, along with apheresis and blood sample collections. Recipients undergo myeloablative conditioning and haploidentical stem cell transplant from vaccinated donors. They then follow one of three treatment plans involving doses of the CMV-MVA Triplex vaccine given intramuscularly on days 28, 56, and 100 after transplant, combined with letermovir given either for 7 to 28 days or 7 to 100 days, or no letermovir. Treatment continues unless disease progresses or side effects become unacceptable. Participants have blood samples collected throughout the study to monitor CMV infection and immune responses. After treatment, recipients are followed every two weeks until day 180 and then again at day 365 post-transplant. Researchers measure CMV reactivation prompting antiviral therapy, CMV disease occurrence, side effects, graft-versus-host disease, survival, and immune system markers to understand the vaccines impact and safety.

A Vaccine (CMV-MVA Triplex Vaccine) for the Enhancement of CMV-Specific Immunity and the Prevention of CMV Viremia in Patients Undergoing Haploidentical Hematopoietic Stem Cell Transplant