Therapeutic drug monitoring of letermovir in allogeneic hematopoietic cell transplant recipients: where are we?

Letermovir meets several criteria for TDM including large inter-individual pharmacokinetic variability and exposure-response relationship albeit, the latter has not been consistently demonstrated. Randomized controlled trials are needed to determine the clinical benefit of letermovir TDM in HSCT recipients. Furthermore, studies are warranted to characterize letermovir pharmacokinetics in situations encountered in clinical practice (complex drug-drug interactions and/or organ dysfunction) and to determine letermovir optimal dosing in the pediatric population.