Pharmacokinetic Analysis Driven Letermovir Dosing in Pediatric
Hematopoietic Cell Transplantation Patients with resistant CMV disease.
Cytomegalovirus (CMV) reactivation in CMV-seropositive patients after
haploidentical T-cell receptor αβ+/CD19+ depleted hematopoietic cell
transplant (HCT) is high. Due to delayed CMV-specific immune
reconstitution, patients may require prolonged antiviral therapy
including secondary prophylaxis (SP). Valganciclovir is preferred for
SP, however, antiviral options for SP could be limited in the setting of
resistant CMV. We report successful off-label use of letermovir for SP
in a haploidentical TCRαβ+/CD19+ depleted pediatric HCT recipient with
resistant CMV disease, its pharmacokinetic parameters, and dose
titration based on area under time concentration curve.