Valganciclovir therapeutic drug monitoring-guided dosing for cytomegalovirus prophylaxis in lung transplant patients.

INTRODUCTION

Valganciclovir is used for cytomegalovirus (CMV) prophylaxis after lung transplantation. However, its use is limited by hematological toxicity. This study evaluated whether therapeutic drug monitoring (TDM)-guided valganciclovir dosing reduces toxicity and improves prophylaxis continuation compared to conventional (non-TDM-guided) dosing.

METHODS

This prospective cohort study with a historical control included lung transplant recipients who received valganciclovir prophylaxis at Kyoto University Hospital between April 2021 and March 2025. The TDM-guided group (April 2023 to March 2025) consisted of patients whose valganciclovir dosing was adjusted to maintain ganciclovir trough concentrations within 300-800 ng/mL. The control group (April 2021 to March 2023) comprised patients who received conventional dosing. The observation period was 3 months post-initiation. The primary outcome was valganciclovir discontinuation due to adverse events; secondary outcomes included valganciclovir-related adverse events and CMV infection during prophylaxis.

RESULTS

Eighty-seven patients were included (control, 42; TDM-guided, 45). The proportions achieving the target trough ganciclovir concentrations were 40.5% and 62.2%, respectively. Valganciclovir discontinuation occurred in 35.7% of controls and 11.1% of TDM-guided patients (hazard ratio, 0.303 [95% confidence interval, 0.126 to 0.730]). Severe leukopenia and neutropenia (defined using Common Terminology Criteria for Adverse Events version 5.0; grade ≥3) occurred more frequently in the control group (19.1% vs. 2.2%). One control patient developed CMV infection during prophylaxis, whereas none did in the TDM-guided group.

CONCLUSION

TDM-guided valganciclovir dosing may reduce hematologic toxicity and improve prophylactic continuation in lung transplant recipients, potentially by avoiding excessive ganciclovir exposure, particularly at trough concentrations above 800 ng/mL.