Real-life data on the efficacy and safety of letermovir for cytomegalovirus prophylaxis in high-risk pediatric patients: a single-center analysis.

Abstract

Background: Letermovir (LET) is approved for the prophylaxis of cytomegalovirus (CMV) infection and disease in adult hematopoietic stem cell transplantation (HSCT) patients up to day 100. The use of LET in the pediatric HSCT population lacks extensive real-world research, especially for high-risk pediatric patients with CMV reactivation. The aim of our study was retrospectively analyzed the efficacy and safety of LET in high-risk pediatric patients with CMV activation, and conducted a preliminary exploration of its duration of use.

Methods: This was a single-center, retrospective study. A total of 123 patients under 18 years of age who were at high risk of CMV reactivation were included, with 61 of them receiving LET for prophylaxis. The median duration was 100 days (ranging from 52 to 298 days). The primary endpoint was the proportion of patients with clinically significant CMV infection (CsCMVi) at 24 weeks post-transplantation. The secondary endpoints were the proportion of patients with CsCMVi before week 14 and the timing of CMV infection. Additionally, we also assessed related adverse reactions.

Results: The proportion of CMV reactivation at 24 weeks post-transplantation in the LET group was significantly lower than that in the control group (8.20% vs. 43.55%, P<0.001). The secondary endpoint was the proportion of CMV reactivation in the LET group and it was also significantly lower than that of the control group at week 14 (6.56% vs. 41.94%, P<0.001). The proportion of CMV reactivation at 24 weeks post-transplantation in patients who used LET for more than 100 days was significantly lower than that in the control group (5.89% vs. 11.10%, P=0.009).

Conclusions: LET can effectively prevent CMV reactivation in patients under 18 years of age and demonstrates good safety. For pediatric patients at high risk of CMV reactivation, extending the duration of prophylaxis beyond 100 days may be beneficial.