The purpose of this clinical trial is to investigate the efficacy of the EBV mRNA vaccine (WGc-0401 injection) in preventing EBV-related diseases after allogeneic hematopoietic stem cell transplantation (allo-HSCT), and to evaluate the safety and efficacy of this vaccine in patients following allo-HSCT.
The main study questions are:
- The incidence of grade III-IV acute graft-versus-host disease (aGVHD) within 100 days, and the occurrence of ≥ grade 3 adverse events (AEs) that are possibly or definitely related to the vaccine, in patients receiving EBV mRNA vaccination after allo-HSCT.
- To determine the optimal biological dose (OBD) of the EBV mRNA vaccine in patients after allo-HSCT among the dose levels of 25μg, 50μg, 75μg, or 100μg.
- EBV-ELISpot levels, the incidence of EBV viremia (EBV DNAemia), the incidence of post-transplant lymphoproliferative disorders (PTLD), disease relapse rate during follow-up, non-relapse mortality (NRM), and immunogenicity indicators (IFN-γ+ T cells, immune cell analysis, cytokine profiles, EBV glycoprotein antigen antibodies).
Participants will:
- Receive three intramuscular injections of the EBV mRNA vaccine on days 30, 44, and 81 after allogeneic hematopoietic stem cell transplantation (d30, d44, d81).
- Be hospitalized for at least 72 hours after each vaccination for close monitoring (with a focus on CRS and aGVHD), and undergo intensive safety assessments throughout the dose-escalation period (at least 28 days).
- Return for clinical visits on days 7 (d37, d51, d88), day 14 (d58), and day 180 (d180) after vaccination for EBV-ELISpot, EBV-DNA quantification, and immunogenicity testing, with continued long-term follow-up to evaluate safety and the persistence of vaccine-induced immune responses.