Hybrid Ganciclovir/Valacyclovir Prophylaxis Reduces CMV Reactivation in High-Risk Allogeneic Stem Cell Transplant Recipients.

Background: Cytomegalovirus (CMV) reactivation remains a critical concern following allogeneic hematopoietic stem cell transplantation (allo-HSCT), particularly in CMV-seropositive patients undergoing allo-HSCT from alternative donors. This study explored whether a hybrid CMV prophylaxis regimen would be more effective than the standard preemptive regimen in resource-limited settings where Letermovir is unavailable or cost-prohibitive. Materials and Methods: This prospective single-center cohort study included adult patients with acute leukemia who received allo-HSCT from alternative donors between November 2018 and May 2022. The primary outcome was the evaluation of the CMV reactivation incidence in allo-HSCT patients receiving the hybrid CMV prophylaxis regimen comprising pretransplant ganciclovir followed by high-dose valacyclovir compared with the control patients who received the preemptive regimen. Secondary outcomes included overall survival (OS), disease-free survival (DFS), GVHD-free relapse-free survival (GRFS), and non-relapse mortality (NRM) between the two groups.      Results: A total of 80 patients, 34 receiving hybrid CMV prophylaxis and 46 receiving the preemptive protocol. The hybrid prophylaxis group exhibited a significantly lower incidence of CMV reactivation at 90 days post-transplantation (34% vs. 82%, P = 0.000). However, no statistically significant differences were observed in the overall survival, disease-free survival, or non-relapse mortality. Conclusion: The hybrid regimen reduced CMV reactivation in high-risk HSCT recipients but did not improve survival outcomes, offering a practical alternative in settings with limited access to Letermovir.