Secondary Prophylaxis With Bioequivalent Generic Letermovir in Haploidentical Hematopoietic Stem Cell Transplantation: A Case Report.

Cytomegalovirus (CMV) reactivation poses a significant risk post-allogeneic hematopoietic stem cell transplantation (HSCT), particularly in high-risk settings. This report details the clinical course of a relapsed acute myeloid leukemia patient who underwent haploidentical HSCT following graft failure linked to CMV viremia. Letermovir prophylaxis effectively suppressed CMV but was discontinued on day +60, following which the patient experienced transient reactivation. The episode was successfully managed in the outpatient setting with oral valganciclovir. This case highlights the importance of sustained CMV prophylaxis and the role of accessible antiviral strategies in optimizing transplant outcomes.