Safety and efficacy of weight-based ganciclovir dosing strategies in overweight/obese patients.

Background: The management of cytomegalovirus (CMV) is particularly challenging as both CMV and its usual first-line treatment, ganciclovir, are associated with neutropenia. Ganciclovir dosing is weight-based, most commonly utilizing total body weight (TBW). The subsequent high doses of ganciclovir in overweight/obese patients may increase the risk of toxicity. Utilizing adjusted body weight (AdjBW) dosing may help mitigate this risk. Therefore, the objective of this study was to evaluate the difference in toxicity and efficacy between TBW and AdjBW ganciclovir dosing strategies in overweight/obese patients.

Methods: This retrospective study conducted safety and efficacy analyses of ganciclovir courses (≥72 h) used as CMV treatment. The primary safety outcome was the incidence of neutropenia (absolute neutrophil count <1000 cells/μL), and the primary efficacy outcome was a 2-log decrease in CMV polymerase chain reaction within 4 weeks following ganciclovir initiation. In both analyses, courses were excluded in which ganciclovir was dosed outside of specified renal dosing parameters for >20% of the course.

Results: Among the 253 courses in the safety cohort, there was no difference in the incidence of neutropenia (17.4% vs. 13.5%, p = .50) in AdjBW compared to TBW dosing. In the 62 courses evaluating efficacy, there was no statistical difference between AdjBW and TBW dosing (60.0% vs. 45.2%, p = .28). No subgroups were identified in which AdjBW dosing was advantageous.

Conclusion: Utilization of AdjBW ganciclovir dosing did not result in decreased neutropenia or treatment efficacy as compared to TBW dosing. Further studies with larger patient populations would be beneficial to confirm these findings.