Determination of Letermovir Serum Levels Can Be Useful in High-Risk Clinical Settings

Therapeutic Drug Monitoring of Orally Administered Letermovir Prophylaxis in Allogeneic Hematopoietic Stem Cell Transplant Recipients

“…We observed a median letermovir-C trough of 286 μg/L, which is consistent with previously reported data in healthy volunteers who received ascending doses of letermovir with a reported C trough of 193 μg/L ( 13 ). In contrast, median untimed letermovir concentrations in 26 patients of 2,246 μg/L, ranging from not detectable to 24,250 μg/L, have been reported in the organ transplant literature ( 14 ). It is likely that the use of untimed sample collection instead of C trough , as well as differences in the testing method, might have contributed to this large variability in reported concentrations.…”

Lactic acidosis after allogeneic haematopoietic stem cell transplantation potentially related to letermovir

“…No case of lactic acidosis was documented. Other studies coming from the organ transplant literature have shown higher untimed letermovir concentrations, ranging from not detectable to 24 250 μg/L 6 . In a series of 74 letermovir trough samples obtained in patients receiving oral letermovir in real‐life conditions, the mean trough concentration was 3397 ± 2531 μg/L 7 .…”

Letermovir for cytomegalovirus primary prophylaxis in a multiple abdominal/small bowel transplant recipient

“…Furthermore, Isberner et al reported much higher trough letermovir concentrations, with a mean of 1′970 mcg/l among 21 trough samples in SOT recipients. 4 It is likely that differences in measuring methods may, in part, explain the large variability in the described concentrations. The higher letermovir trough level postileostomy closure may suggest suboptimal absorption in the presence of ileostomy.…”