Letermovir prophylaxis for cytomegalovirus infection in hematopoietic transplantation with post-transplant cyclophosphamide.

INTRODUCTION

Post-transplant cyclophosphamide is a widely used platform for graft-versus-host disease prophylaxis in allogeneic hematopoietic cell transplantation (allo-HCT). However, it is associated with a higher incidence of cytomegalovirus (CMV) infection, regardless of donor type. Primary prophylaxis with letermovir has been shown to reduce the rate of CMV infection.

MATERIALS AND

METHODS

This multicenter, retrospective cohort study aimed to evaluate the efficacy of letermovir for CMV prophylaxis in CMV seropositive patients undergoing alternative donor allo-HCT, using post-transplantation cyclophosphamide-based graftversus-host disease prophylaxis compared to those who did not receive primary prophylaxis in a real-world setting in Argentina.

RESULTS

A total of 136 adult patients who underwent allo-HCT between January 2018 and December 2022 were analyzed, of whom 36 received letermovir. Most of the patients underwent haploidentical allo-HCT (82%). The median follow-up time was shorter for the letermovir group, 7.6 months (IQR 2.9-13.7) vs. 13.2 months (IQR: 4.4-27.6), due to the more recent introduction of letermovir in Argentina. The cumulative incidence of CMV infection at day +100 was significantly lower in patients treated with letermovir: 14% (CI 5-27) vs. 56% (CI 46-65), p=0.0003, and this benefit persisted at one year: 37% (CI 21-53) vs. 56% (CI 46-65), p=0.0019). The 1-year cumulative incidence of non-relapse mortality was similar between patients with and without letermovir treatment (26% vs. 28%), as was overall survival (62% vs. 62%).

DISCUSSION: In summary, letermovir effectively prevented CMV infection in this high-risk population of allo-HCT recipients.