BACKGROUND: In recent years, letermovir has been routinely used for cytomegalovirus (CMV) infection prophylaxis in patients receiving allogeneic hematopoietic stem-cell transplantation (HSCT). The reduction effect of letermovir on CMV infection rates and the impact on survival have been studied, but other potential benefits of letermovir remain underexplored.

METHODS: This retrospective study included patients who underwent first-time allogeneic HSCT between October 2013 and August 2023. We compared the length of hospital stay between eras before and after the introduction of letermovir ("nonletermovir group" and "letermovir group," respectively). Secondary outcomes included clinically significant CMV infection rates and hospitalization costs.

RESULTS: A total of 59 patients were analyzed in the nonletermovir group and 65 patients in the letermovir group. The median length of hospital stay was 51 days in the nonletermovir group and 42 days in the letermovir group (p < 0.001). Among standard-risk disease patients, the letermovir group also had significantly shorter hospital stays (p = 0.0048). Additionally, the cumulative incidence of clinically significant CMV infection and grade II-IV acute graft-versus-host disease were both lower in the letermovir group. Hospitalization costs were not significantly different between the two groups.

CONCLUSION: The length of hospital stays after HSCT was observed to be shorter following the introduction of letermovir in this study. This reduction in hospital stays did not decrease hospitalization costs in relation to allogeneic HSCT, but it may alleviate the burden on both patients and healthcare providers.