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 received hybrid cmv prophylaxis, and 46 received 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 overall survival, disease-free survival, or non-relapse mortality rates. 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.