Letermovir use in children after hematopoietic cell transplantation: summary of reported data

Abstract

Introduction: Letermovir (LMV) is approved for primary prophylaxis of cytomegalovirus infection (CMVi) in CMV-seropositive adult patients undergoing allogeneic hematopoietic stem cell transplantation. However, it is not registered for CMVi preemptive treatment, CMVi secondary prophylaxis, or the treatment of CMV disease. There is very limited data regarding LMV’s use in pediatric patients, as it has not been approved so far as any kind of treatment in children, with its use remaining off label. The aim of this study was to summarize reported data on the efficacy and safety of LMV in pediatric patients. Material and methods: Studies and case reports regarding LMV’s use in pediatric patients were searched in PubMed. Results: Overall, nine reports that fulfilled the search criteria, published between 2019 and 2022, were found and analyzed. The total number of cases involved in research was 46 with patient age ranging from 2–19 years; one child was counted twice due to another transplant. The most common serostatus of donor/recipient was D+/R+ (47%), followed by D–/R+ (42%), then D+/R– (2%), and then unknown (9%). Most patients had received the transplant from a matched unrelated donor (40%). There were 47 incidents of LMV administration as CMV management strategy. The analyzed patients received LMV as primary prophylaxis (74%), secondary prophylaxis (15%), pre-emptive therapy (6%), or treatment of CMV disease (4%). One patient received LMV as a treatment and then as a secondary prophylaxis. In 44/46 (95.6%) cases, no symptomatic CMVi occurred during LMV administration, with only transient CMV DNA-emia present on rare occasions. Conclusion: The use of LMV is safe in pediatric patients.