Pharmacokinetics and Pharmacodynamics of (Val)Ganciclovir in Infants with Congenital Cytomegalovirus

Ganciclovir (GCV), and its orally available pro-drug valganciclovir (VGCV), are preferred therapies for treating congenital cytomegalovirus (cCMV), however, their use carries a significant risk of neutropenia for the child. This risk limits dosing and effectiveness of VGCV, particularly in the treatment of infants with cCMV infection, who are at increased risk for sensorineural hearing loss (SNHL). We hypothesized that an improved understanding of the pharmacokinetics (PK) and pharmacodynamics (PD) of VGCV in cCMV-infected infants at risk for SNHL would inform strategies for optimizing safe and effective VGCV dosing. Participants were enrolled in one of two clinical studies interrogating the PK, safety, and efficacy of VGCV treatment in cCMV-infected infants at risk for SNHL. GCV exhibited a short median half-life of 2.02 h and the median (range) area under the 24 h concentration-time curve (AUC24) was 60.8 (26.8, 99.4) g*h/mL. An AUC24 > 70 g*h/mL was associated with an elevated risk of neutropenia (Fisher's Exact p = 0.029). No associations between GCV PK and hearing outcomes were observed. Taken together, these results indicate vast inter-individual variability in GCV PK that is associated with dose-related toxicity, supporting the need for individualized dosing in the cCMV-infected population.